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  1. #1
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    Tubeless = Handling improvement?

    Have any of you noticed an improvement in handling after switching to tubeless? I'll be converting soon but keeping my AKA 2.2 (29s) and marrying them to Arch wheels. Wanting to drop the tubed pressures I currently run (26-28 psi) in hopes of a handling benefit, specifically cornering.
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    Yes. Absent the tube, and with the lower pressure you can run, you gain two ways:

    Bigger contact patch for better traction
    Easier deformation for lower rolling resistance and more compliant ride

    Experiment with the tire pressure to get the most benefit for the tires you run and the trails you ride.
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    Quote Originally Posted by CCMTB View Post
    Have any of you noticed an improvement in handling after switching to tubeless? I'll be converting soon but keeping my AKA 2.2 (29s) and marrying them to Arch wheels. Wanting to drop the tubed pressures I currently run (26-28 psi) in hopes of a handling benefit, specifically cornering.
    With the same tire? Not really.

    In fact, taking the inner tube out of a tire has usually required me to increase the pressure to keep it from squirming in the corners. With most tires squirming limits how low I can go with the pressure, not pinch flats.
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  4. #4
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    People get a little nuts about the benefits of tubeless. 26psi is pretty low already. For me, lower than that and the tire is too squirmy. A bit more traction doesnt compensate for the wiggly tire.

  5. #5
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    one thing i noticed outright is how much better and easier it is for me to go uphill on a rocky slope (rocks partially buried the size of a baseball cap). for me tubeless is a must when you go on trails. provided you find the right tire pressure for your style. its pointless to go tubeless i you run high pressures (40psi).

    i am still trying to figure out how low can i go in terms of pressure. at the moment i am at 30 front 33 rear.

  6. #6
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    I definitely push the limits of tubed. At 26 psi there is the occasional 'rim hit' but the pressure feels really good, and I love the tire compliance, especially while climbing. When the tire absorbs the hit, rather than bouncing off, it makes a huge difference in momentum. From the responses, I gather it may not be that noticeable. There's other benefits, I know, but I was wondering if a handling improvement was one of those.

    Anyway, thanks all for the input.
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    Quote Originally Posted by CCMTB View Post
    I definitely push the limits of tubed. At 26 psi there is the occasional 'rim hit' but the pressure feels really good, and I love the tire compliance, especially while climbing. When the tire absorbs the hit, rather than bouncing off, it makes a huge difference in momentum. From the responses, I gather it may not be that noticeable. There's other benefits, I know, but I was wondering if a handling improvement was one of those.

    Anyway, thanks all for the input.
    If you are getting rim hits with tubes, you will get rim hits without tubes, even at the same pressure. And you can still pinch flat, but you will be cutting the tire casing rather than the tube.
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  8. #8
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    I gotta disagree with Shiggy.

    Tubeless allows me to run much lower air pressure and flat less. I usually run 18-22psi is a 2.2 tire. If grip levels are good I will run higher pressure to prevent squirm and if grip levels are low I drop the air pressure for grip.

    I wish I could say that I didn't flat at those pressures with tubes, but unfortunately I do. As Shiggy mentioned it is possible to pinch a tubeless tire, but it actually really hard to do. In 8 years of running tubeless tires I actually never have pinched one (I have had flats but not pinches). However, in my riding career the number of tubes I have pinched is in the triple digits.

    The big trade off with tubeless is it can be a pain to work with. If you like to change tires a lot then you are not going to like tubeless.
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    Have someone actually pinched a tubeless tire or its only possibility? J have never managed .

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    Quote Originally Posted by shiggy View Post
    In fact, taking the inner tube out of a tire has usually required me to increase the pressure to keep it from squirming in the corners. With most tires squirming limits how low I can go with the pressure, not pinch flats.
    How does a soft and flexible inner tube make a tire firmer?

  11. #11
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    Quote Originally Posted by beanbag View Post
    How does a soft and flexible inner tube make a tire firmer?
    With that logic going tubeless should make no difference at all?

    I'm with shiggy I usually add 1 psi going tubeless.If you run big volume tires there is less chance of snakebite problems. Worst combo for snakebites are low volume tires and wider rims.

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    If your tires get squirmy without pinch-flatting, I have to ask what types of trails and tires are you using. If my tire is squirmy, I am just about guaranteed to pinch flat on a rock or root. Do you guys have rocky and/or rooty trails?

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    A lot of the "squirm talk" is very tire/rim specific. I would also say that there are different levels of squirm and people have different tolerances for it and the tolerance can vary with different types of trails/terrain.

    I don't mind a little bit of squirm in exchange for a lot of compliance/grip for slow technical rooty/rocky stuff. But for high speed flowy/DH, I can't tolerate much squirm at all.

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    For me, the only downside of running tubeless on rims like Stan's is that they can be harder to set up for some people and some tire combinations.

    The flexibility of running tire pressure based on terrain NOT based on pinch flat avoidance is huge.
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    Quote Originally Posted by mountainbiker24 View Post
    If your tires get squirmy without pinch-flatting, I have to ask what types of trails and tires are you using. If my tire is squirmy, I am just about guaranteed to pinch flat on a rock or root. Do you guys have rocky and/or rooty trails?
    Yes.. but I dont pinch flat, I bang or dent rims.

    Ive heard some people say they ride mild xc trails and have to run 35+ psi or they pinch flat the entire ride. Theres some factor thats missing, I dont get how some people pinch SO often.

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    Quote Originally Posted by One Pivot View Post

    Ive heard some people say they ride mild xc trails and have to run 35+ psi or they pinch flat the entire ride. Theres some factor thats missing, I dont get how some people pinch SO often.
    LOTS of variables . . .
    Riding style, rider weight, HT vs. FS, incorrect suspension set-up, bad tire gauge, tube type, tire type, tire size, etc., etc.
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    Quote Originally Posted by One Pivot View Post
    Yes.. but I dont pinch flat, I bang or dent rims.

    Ive heard some people say they ride mild xc trails and have to run 35+ psi or they pinch flat the entire ride. Theres some factor thats missing, I dont get how some people pinch SO often.
    I would pinch flat "too often", but definitely not every ride at 35 PSI. To keep out of trouble, I ran closer to 37.5-40 PSI. At 30 PSI I was felt guaranteed to flat.

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    Quote Originally Posted by Stumpjumpy View Post
    LOTS of variables . . .
    Riding style, rider weight, HT vs. FS, incorrect suspension set-up, bad tire gauge, tube type, tire type, tire size, etc., etc.
    And type of things you hit.
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    Quote Originally Posted by CCMTB View Post
    Have any of you noticed an improvement in handling after switching to tubeless? I'll be converting soon but keeping my AKA 2.2 (29s) and marrying them to Arch wheels. Wanting to drop the tubed pressures I currently run (26-28 psi) in hopes of a handling benefit, specifically cornering.
    I run a lower pressure when tubeless, than with tubes.

    24/28 psi...vs 28/30 psi....

    I might be able to run the same pressure but I just don't feel comfortable risking pinch flats...


    So yeah I notice a difference in handling.

  20. #20
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    Does a reinforced sidewall reduce the squirming?

    I

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    Quote Originally Posted by beanbag View Post
    How does a soft and flexible inner tube make a tire firmer?
    The same way a layer of rubber in/on the casing of a tire does. When the tire/tube is under pressure the inner tube is basically part of the tire.
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    Quote Originally Posted by vanamees View Post
    Have someone actually pinched a tubeless tire or its only possibility? J have never managed .
    I have seen pinch flatted/cut casings. It is also likely the at least some sidewall tears in "converted" tires is from previous damage to the casing when the tire has bottomed out. Inner tubes do provide a cushion for the tire in a hit.
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    Quote Originally Posted by bitewerks View Post
    Does a reinforced sidewall reduce the squirming?

    I
    At a given pressure, yes. But for the same tire pressure the reinforced tire will usually feel harsher.
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  24. #24
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    That's what I thought. I use tires with reinforced sidewalls just as precaution from cuts (cut one cheap tire on the sidewall), etc. There are no highspeed corners on my local trails so I've never felt squirming like people describe. I have never felt the rim getting hit either. I just go by 'feel' as far as pressures go. Rather start off a ride with a little too much air pressure & drop it if things feel too rough.

  25. #25
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    I am with Shiggy too, especially with respect to DH. Lots of reason to go tubeless, but better handling is nowhere on top of the list.

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    I went ghetto tubeless on my front tire just out of curiosity & after getting thorns but no flats, that's reason enough to keep running tl for me.

  27. #27
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    Quote Originally Posted by shiggy View Post
    The same way a layer of rubber in/on the casing of a tire does. When the tire/tube is under pressure the inner tube is basically part of the tire.
    That doesn't make sense to me. If I glue butyl rubber to the sidewalls of my tires, I don't expect it to make the tire any stiffer.

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    Quote Originally Posted by beanbag View Post
    That doesn't make sense to me. If I glue butyl rubber to the sidewalls of my tires, I don't expect it to make the tire any stiffer.
    so you don't see how basically doubling the thickness of a tire casing will make it stiffer?
    go try to crumple a sheet of 1mm thick aluminum by hand compared to a sheet of aluminum foil and tell me if the results are the same.

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    Quote Originally Posted by peabody View Post
    so you don't see how basically doubling the thickness of a tire casing will make it stiffer?
    No, I don't. The "stiffness" of a tires comes about because the casing has fibers that prevent it from stretching and thus becomes stiff upon inflation. An inner tube doesn't have this property.

    Have you noticed how a mylar balloon feels "stiff" while a latex one doesn't?

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    Quote Originally Posted by beanbag View Post
    No, I don't. The "stiffness" of a tires comes about because the casing has fibers that prevent it from stretching and thus becomes stiff upon inflation. An inner tube doesn't have this property.

    Have you noticed how a mylar balloon feels "stiff" while a latex one doesn't?
    it absolutely adds structure, not the same properties as the tire, but structure none the less. you are saying then that latex has no physical properties as a material if it adds nothing. if you look at road tires, they will inflate with a tube to 120psi no problem, remove the tube and 120psi will blow it off the rim. that was an early problem in developing road tubeless and why they went with a carbon bead.

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    Quote Originally Posted by peabody View Post
    it absolutely adds structure, not the same properties as the tire, but structure none the less.
    Ok, what structure does it add?

    if you look at road tires, they will inflate with a tube to 120psi no problem, remove the tube and 120psi will blow it off the rim. that was an early problem in developing road tubeless and why they went with a carbon bead.
    What is the mechanism for a road tire blow-off, and how does an inner tube prevent it?

  32. #32
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    Quote Originally Posted by beanbag View Post
    No, I don't. The "stiffness" of a tires comes about because the casing has fibers that prevent it from stretching and thus becomes stiff upon inflation. An inner tube doesn't have this property.
    The tube is constrained by the tire casing.. just like the rubber on the tire is. The tube becomes another layer of rubber on the tire. Friction between the tube and tire cause a stiff weird feeling.

    Thats a huge reason why people powder their tubes..

  33. #33
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    I'm with Peabody and others who say the tube will naturally make the tire stiffer - any time you layer materials together it adds some level of stiffness. Think of plywood, skis, 3ply gore-tex vs 1ply. Now, will the stiffness be noticeable? In all those examples, the layers are bonded together with glue to add rigidity, while tube+tire have only whatever natural stickiness going between them. It would be easy to test with a couple buddies if you cared enough to do a little experiment.

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    The tube also has ~30psi of pressure adhering it to the inside of the tire. For most tubes, thats another almost 1mm of rubber.

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    Quote Originally Posted by beanbag View Post
    Ok, what structure does it add?
    Butyl rubber is a viscoelastic material, so every time it is flexed it absorbs energy, and when it returns to its unflexed state it returns some energy (but not all). The resistance to flex is what adds 'structure' to the tire. It's not something one could feel by slowly pressing on the sidewall of a tire with one's thumb, but one can definitely feel it while riding because each element of the tire is flexing and unflexing extremely fast. Try an experiment: throw a thick tube in a tire, ride it, then throw a thin tube in. Try to ignore the weight difference. While running the same pressures, you'll notice that when cornering hard the tire rolls less laterally, and it has a more 'dampened' feel with the thicker tube.



    Quote Originally Posted by beanbag View Post
    What is the mechanism for a road tire blow-off, and how does an inner tube prevent it?
    I'm not sure how this is germane to the conversation, but an inner tube will exert more (lateral) force onto the bead of a tire, enabling the bead hook of the rim to help retain the bead. In a tubeless application, the bead hook performs less of role in bead retention.

  36. #36
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    Quote Originally Posted by bholwell View Post
    Butyl rubber is a viscoelastic material, so every time it is flexed it absorbs energy, and when it returns to its unflexed state it returns some energy (but not all). The resistance to flex is what adds 'structure' to the tire. It's not something one could feel by slowly pressing on the sidewall of a tire with one's thumb, but one can definitely feel it while riding because each element of the tire is flexing and unflexing extremely fast. Try an experiment: throw a thick tube in a tire, ride it, then throw a thin tube in. Try to ignore the weight difference. While running the same pressures, you'll notice that when cornering hard the tire rolls less laterally, and it has a more 'dampened' feel with the thicker tube.
    While I don't disagree that adding butyl rubber increases damping, I have a hard time believing that given the high stiffness of the tire compared to the small amount of damping plus the low frequencies associated with tire lateral deflection /squirm of maybe 2-3 cycles per second, that this damping has much of an effect. Certainly it can damp internal modes, like the ping you get when you flick the sidewall with your fingernail. That can create a psychoacoustic effect of "more damping", just like carbon fiber components.

    But if I were to believe you that the damping in a butyl inner tube is enough to make a tire "roll less laterally", then wouldn't I also be forced to make these conclusions as well?

    - Adding sealant or Slime goop reduces squirminess because all that sloshing around creates damping.

    - A latex inner tube does not reduce squirminess because it has much less damping than butyl rubber.

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    Quote Originally Posted by beanbag View Post
    While I don't disagree that adding butyl rubber increases damping, I have a hard time believing that given the high stiffness of the tire compared to the small amount of damping plus the low frequencies associated with tire lateral deflection /squirm of maybe 2-3 cycles per second, that this damping has much of an effect. Certainly it can damp internal modes, like the ping you get when you flick the sidewall with your fingernail. That can create a psychoacoustic effect of "more damping", just like carbon fiber components.

    But if I were to believe you that the damping in a butyl inner tube is enough to make a tire "roll less laterally", then wouldn't I also be forced to make these conclusions as well?

    - Adding sealant or Slime goop reduces squirminess because all that sloshing around creates damping.

    - A latex inner tube does not reduce squirminess because it has much less damping than butyl rubber.
    Yes to the latex inner tube, no to the sealant. But I'm not asking you to take my word for it. Try it yourself, preferably with a tire with a thin casing and a narrowish rim.

  38. #38
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    Quote Originally Posted by CCMTB View Post
    Have any of you noticed an improvement in handling after switching to tubeless? I'll be converting soon but keeping my AKA 2.2 (29s) and marrying them to Arch wheels. Wanting to drop the tubed pressures I currently run (26-28 psi) in hopes of a handling benefit, specifically cornering.
    I did find that at a similar pressure, Switching to tubeless (same tires) felt a tad more supple. I assume it is for the same reason that going from a thicker to a thinner tube feels more supple.

    However, I did not reap much benefit with regards to pressure. I was only able to drop my pressure about 2-3 psi in the rear. Problem is that pinch flats are just a mild form of rim strikes. In the end, tubeless has only allowed me to drop the rear pressure about 2-3 psi before I started getting rim strikes that I could feel on the rim (Stans Flows). The front pressure has not changed, as that was determined by when the tires stared squirming, and that has not really changed.
    15mm is a second-best solution to a problem that was already solved.

  39. #39
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    Quote Originally Posted by One Pivot View Post
    The tube is constrained by the tire casing.. just like the rubber on the tire is. The tube becomes another layer of rubber on the tire. Friction between the tube and tire cause a stiff weird feeling.

    Thats a huge reason why people powder their tubes..
    People powder tubes because of myth.

    The tube is constrained by the casing but that doesn't mean it "becomes another layer of rubber on the tire".

    If there was friction between the tube and tire that would be direct evidence that the tube isn't simply another layer of the tire.

    All this arguing back and forth and no concept of the extent to which a tube changes anything. There isn't even a discussion of what kind of tube! There is no way anyone could detect the contribution of a latex tube, for example. Obviously, a thin tube will have less effect than a thin one, whatever that effect is.

    This is classic armchair engineering.

    Edit: Latex tubes and thick/thin mentioned later. As Bhowell said, hysteresis of material plays an important role.

  40. #40
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    I pinch flat with tubes but don't with tubeless. We have rocky technical trails here and running tubeless allows for lower pressure which in turn prevents the bike from bouncing around and allows the tire to conform better thus increasing ride quality and traction. Caveat is that too stiff a suspension set up would nullify the lower tire pressure gains.

  41. #41
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    Quote Originally Posted by craigsj View Post
    People powder tubes because of myth.
    How it is it a myth when it changes the way the tire feels?

    Its the same with tubeless.. try to find testing that proves anything about tubeless and theres really very little out there to suggest tangible gains in anything. Everyone that goes tubeless feels a difference though.

    Or even better.. start up analytic cycling and see what kind of difference dropping a pound of wheel makes. Its damn near irrelevant. Ride a pound less wheel and it certainly feels different. Component stiffness is the same thing.

    Theres a big gap with "feel" that engineering explains very poorly.

    Either way.. you called it arm chair engineering, yet agreed that thickness and hysteresis plays a big role.. which is what everyone was saying to begin with . Do you disagree with things just to be disagreeable?

  42. #42
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    Quote Originally Posted by One Pivot View Post
    How it is it a myth when it changes the way the tire feels?

    Its the same with tubeless.. try to find testing that proves anything about tubeless and theres really very little out there to suggest tangible gains in anything. Everyone that goes tubeless feels a difference though.
    Not everyone. I do not and there are others who post here who do not. I understand that conflicts with certain world views.

    Tubes were powdered in car and motorcycle tires for a good reason (so they did not literally become a layer of the tire!!!). That reason doesn't exist for bicycles yet the practice was carried over. It doesn't do anything. The real issue is not that, though, it's that your claims that tube/tire friction is the explanation is openly contradictory to your claim that the tube effectively becomes a layer of the tire. Neither of these things is true and both can clearly not be true.

    Quote Originally Posted by One Pivot View Post
    Or even better.. start up analytic cycling and see what kind of difference dropping a pound of wheel makes. Its damn near irrelevant. Ride a pound less wheel and it certainly feels different.
    I agree, but analytic cycling isn't computing the "feel" of a wheel, it computes the overall contribution of the extra mass to the subset of cycling they model. This is not a contradiction, it is easily explained...at least to the open-minded.

    Quote Originally Posted by One Pivot View Post
    Theres a big gap with "feel" that engineering explains very poorly.
    This assumes "engineering" attempts to explain feel but it does not. There is no reason for such a gap, much less a big one. There is a need for people to cling to beliefs; "feel" works well for that and the bigger the gap the better it works.

    Quote Originally Posted by One Pivot View Post
    Either way.. you called it arm chair engineering, yet agreed that thickness and hysteresis plays a big role.. which is what everyone was saying to begin with . Do you disagree with things just to be disagreeable?
    I'll laugh at your gross misrepresentation of the thread. Why do you have to make it personal?

  43. #43
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    Quote Originally Posted by bholwell View Post
    Try it yourself, preferably with a tire with a thin casing and a narrowish rim.
    I may or may not be able to "feel a difference", but just because something "feels" a certain way does not mean that effect is actually happening. I am already biased with how a tube is supposed to affect a tire anyway, so I will end up making up reasons for why things work out. Can you propose a quantitative test or measurement of the claim that an inner tube "supports" (or damps) the tire and makes it "squirm" less? I might be able to do this test.

  44. #44
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    Tubes are powder to keep them from sticking and easier handling in production. Also so they do not stick in the package when they are folded in the plastic or box. This is for motorcycle and car tubes, I say its the same for bike tubes also.

  45. #45
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    Quote Originally Posted by Joe 29er View Post
    Tubes are powder to keep them from sticking and easier handling in production. Also so they do not stick in the package when they are folded in the plastic or box. This is for motorcycle and car tubes, I say its the same for bike tubes also.
    It is, but that is not the most important reason powdering was used for car and motorcycle tubes. What you are describing is mere convenience, not any kind of important function or performance benefit. It the sole reason for powdering bicycle tubes. Performance benefit is a myth.

  46. #46
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    Quote Originally Posted by beanbag View Post
    While I don't disagree that adding butyl rubber increases damping, I have a hard time believing that given the high stiffness of the tire compared to the small amount of damping plus the low frequencies associated with tire lateral deflection /squirm of maybe 2-3 cycles per second, that this damping has much of an effect. Certainly it can damp internal modes, like the ping you get when you flick the sidewall with your fingernail. That can create a psychoacoustic effect of "more damping", just like carbon fiber components.

    But if I were to believe you that the damping in a butyl inner tube is enough to make a tire "roll less laterally", then wouldn't I also be forced to make these conclusions as well?

    - Adding sealant or Slime goop reduces squirminess because all that sloshing around creates damping.

    - A latex inner tube does not reduce squirminess because it has much less damping than butyl rubber.
    Cutting through all the over thinking bouncing around your skull, take the same tire with tubes and then run it tubeless. It's very obvious that the tubed tire is stiffer at the same pressures.

    Fyi, Stans dries up pretty quickly and even when it's not liquid the tire is more damp. And your sloshing / dampness analogy seems way off considering the minimal amount of liquid.

    Take a woolen stocking cap and see how stiff it is. Now insert an inflated balloon and see how stiff it is.
    Last edited by BumpityBump; 04-06-2012 at 10:53 AM.

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    It could be argued that anything that makes you feel more confident will be faster, even if it doesn't produce a measurable difference in the lab. I personally felt a difference when switching to tubeless. I also noticed a marginal difference when I powdered my tubes. Did either make me faster? Yes, because I felt like the traction was better, and I trusted my tires more.

  48. #48
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    Quote Originally Posted by mountainbiker24 View Post
    It could be argued that anything that makes you feel more confident will be faster, even if it doesn't produce a measurable difference in the lab. I personally felt a difference when switching to tubeless. I also noticed a marginal difference when I powdered my tubes. Did either make me faster? Yes, because I felt like the traction was better, and I trusted my tires more.
    The only mathematical reason for tubeless making you faster is the the lower weight and rotating mass. Less total weight of the bike = less rolling resistance. Less rotating mass = less rolling resistance. Less rolling resistance means that the same work I was putting into moving the bike before should move the bike easier. This also means that since im doing the same thing with less work then I have more power on reserve to add to that.
    2010 Giant Yukon FX
    Pure XCR Wheelset/Geax Saguaro Tires/Tubeless
    Bike Weight Lost: 2.48lbs (1124g)

  49. #49
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    Quote Originally Posted by BumpityBump View Post
    Cutting through all the over thinking bouncing around your skull, take the same tire with tubes and then run it tubeless. It's very obvious that the tubed tire is stiffer at the same pressures.
    I may or may not be able to "feel a difference", but just because something "feels" a certain way does not mean that effect is actually happening. I am already biased with how a tube is supposed to affect a tire anyway, so I will end up making up reasons for why things work out. Can you propose a quantitative test or measurement of the claim that an inner tube makes a tire "stiffer"? I might be able to do this test.

  50. #50
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    Quote Originally Posted by SuperSlow35th View Post
    The only mathematical reason for tubeless making you faster is the the lower weight and rotating mass. Less total weight of the bike = less rolling resistance. Less rotating mass = less rolling resistance. Less rolling resistance means that the same work I was putting into moving the bike before should move the bike easier. This also means that since im doing the same thing with less work then I have more power on reserve to add to that.
    You entirely missed my point, but I'll play along. There is a difference in rolling resistance on uneven ground between a stiffer tire and a more supple tire. Whether it's caused by air pressure, casing, compound, tube, or tubeless, there is a difference.

    My point was that if something makes you feel more confident in your bike, you will be faster. People will often be faster on a new bike because they expect it to be faster. They will push it a little harder because they think it is lighter or has better geometry. The first few rides of the honeymoon phase will be faster than the rides after, when the rider forgets what 2 extra pounds felt like and they feel the suffering a bit more.

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    Quote Originally Posted by beanbag View Post
    I may or may not be able to "feel a difference", but just because something "feels" a certain way does not mean that effect is actually happening. I am already biased with how a tube is supposed to affect a tire anyway, so I will end up making up reasons for why things work out. Can you propose a quantitative test or measurement of the claim that an inner tube makes a tire "stiffer"? I might be able to do this test.
    Here's a test for you. Get one of those super thick tubes and run 10 psi. See how fast you have to hit a curb before you feel the thunk of the tire hitting the rim. Then try the same tire tubeless and hit the same curb at the same speed. I bet you will hear that thunk at a slower speed than you did with the super thick tube in it.

    I used to run a super thick tube on the rear of my bmx bike plus another cut tube wrapped around that to prevent pinch flats. It worked. It felt stiffer, too, because it was stiffer. I realize that there was more rubber to cut through, which helped prevent pinch flats, but the increase in stiffness was obvious.

  52. #52
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    Quote Originally Posted by mountainbiker24 View Post
    Here's a test for you. Get one of those super thick tubes and run 10 psi. See how fast you have to hit a curb before you feel the thunk of the tire hitting the rim. .
    Ummm, I think I'll pass on that, thanks.

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    Quote Originally Posted by beanbag View Post
    That doesn't make sense to me. If I glue butyl rubber to the sidewalls of my tires, I don't expect it to make the tire any stiffer.
    What if you could theoretically glue 10 tubes inside the tire? They are all soft rubber, but would you agree that might make the tire a bit stiffer to flex?


    If your answer is yes, that means adding only one tube, is stiffer too.
    Bend, Oregon

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    Quote Originally Posted by craigsj View Post
    People powder tubes because of myth.

    The tube is constrained by the casing but that doesn't mean it "becomes another layer of rubber on the tire".

    If there was friction between the tube and tire that would be direct evidence that the tube isn't simply another layer of the tire.
    So you are telling me you have never pulled a tube out of a tire, and had to literally stretch it out of the casing, being basically glued inside the tire?
    Bend, Oregon

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    Quote Originally Posted by craigsj View Post
    Tubes were powdered in car and motorcycle tires for a good reason (so they did not literally become a layer of the tire!!!). That reason doesn't exist for bicycles yet the practice was carried over.
    How is a tube "becoming a layer of the tire", in a car or motorcycle possible, but not in a bicycle?
    Bend, Oregon

  56. #56
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    Quote Originally Posted by mountainbiker24 View Post
    It could be argued that anything that makes you feel more confident will be faster, even if it doesn't produce a measurable difference in the lab. I personally felt a difference when switching to tubeless. I also noticed a marginal difference when I powdered my tubes. Did either make me faster? Yes, because I felt like the traction was better, and I trusted my tires more.
    People feel what they want to feel and don't like to hear anything that contradicts their preconceptions.

    One can say the same for the color of their frame. Why should anyone care about how your emotions effect your ride?

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    Quote Originally Posted by craigsj View Post
    People feel what they want to feel and don't like to hear anything that contradicts their preconceptions.

    One can say the same for the color of their frame. Why should anyone care about how your emotions effect your ride?
    Because emotions make us human, and the reason most of us ride mountain bikes is for the experiences and emotions created by those experiences. Whatever makes that experience better makes us feel better, which makes makes us ride better. If you feel confident and happy with your bike, you will be a better rider. You will ride more if you like your bike, take care of it better so it rides better, value the techniques used to ride smoother, and generally become better. I don't give a crap if you care about my emotions or not, but emotions can make or break a ride or race. Never heard of mind over matter? It's all about confidence in yourself and your equipment. If you have doubts about what you're running, you will never let it hang out.

  58. #58
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    Quote Originally Posted by mountainbiker24 View Post
    I don't give a crap if you care about my emotions or not, but emotions can make or break a ride or race.
    But they can't prove that powdering a tube does anything other than make you feel superior.

    This thread is like a bunch of blind men telling each other what the world looks like. You think your imagination matters more than what sighted people have to say.

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    Quote Originally Posted by craigsj View Post
    But they can't prove that powdering a tube does anything other than make you feel superior.

    This thread is like a bunch of blind men telling each other what the world looks like. You think your imagination matters more than what sighted people have to say.
    You're right, it's difficult to prove that powdering a tube makes a difference. However, if they believe that they are benefiting from it, they are better off doing it. It doesn't matter if it actually makes a difference. It does for them, and it might actually make them a better rider because of it. For the record, there is a difference in feel when you powder a tube.

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    Quote Originally Posted by craigsj View Post
    But they can't prove that powdering a tube does anything other than make you feel superior.
    Thing is, preventing the tube from sticking to the inner tire surface, DOES actually have an effect. That is not "feelings".
    Bend, Oregon

  61. #61
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    Quote Originally Posted by thuren View Post
    Thing is, preventing the tube from sticking to the inner tire surface, DOES actually have an effect. That is not "feelings".
    No it doesn't, because it only prevents the tube from sticking temporarily and the tube does not slip on the casing anyway.

    People think whatever they imagine is fact. Google is your friend though. Tube powdering improving performance is a myth.

    You should submit to a blind test where the only difference is powder on the tube and see where it gets you. I bet I could use different tires in that test and you wouldn't tell the difference.

  62. #62
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    Quote Originally Posted by mountainbiker24 View Post
    For the record, there is a difference in feel when you powder a tube.
    Prove it.

    Quote Originally Posted by mountainbiker24 View Post
    It doesn't matter if it actually makes a difference.
    Of course not. People do things in the name of "God" all the time, yet it doesn't matter if "God" exists because they did those things regardless. That's entirely off the original point of why powdering was brought up in the first place.

    "The tube is constrained by the tire casing.. just like the rubber on the tire is. The tube becomes another layer of rubber on the tire. Friction between the tube and tire cause a stiff weird feeling.

    Thats a huge reason why people powder their tubes.."


    There was a false statement that friction between tube and tire was responsible for stiffness and that powdering addressed that. People "believing" or "feeling" that doesn't make it true.

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    Quote Originally Posted by craigsj View Post
    No it doesn't, because it only prevents the tube from sticking temporarily and the tube does not slip on the casing anyway.
    So can you prove it does not slip in the tire casing?
    Bend, Oregon

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    Quote Originally Posted by craigsj View Post
    There was a false statement that friction between tube and tire was responsible for stiffness and that powdering addressed that. People "believing" or "feeling" that doesn't make it true.
    I think they mean LACK of friction between the tire and tube, when they bond together.
    Bend, Oregon

  65. #65
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    Quote Originally Posted by thuren View Post
    So can you prove it does not slip in the tire casing?
    Yes I can but you won't respect it because it conflicts with your opinion. I know how the game works. Can you prove that it does?

    Jobst Brandt has made the case on Sheldon Brown's site. From his article on tube talc, which entirely supports my position, he says:

    "A tube cannot move in a tire when inflated, regardless of what powder is used, because, no translational forces exist, on top of which the holding force between tube and casing is large."

    Go ahead, say Jobst Brandt is wrong because you can "feel" it.

    Quote Originally Posted by thuren View Post
    I think they mean LACK of friction between the tire and tube, when they bond together.
    If he had meant that, he would have corrected his contradiction when it was pointed out to him. The tire and tube NEVER bond together.

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    Quote Originally Posted by craigsj View Post
    Prove it.

    I have proven it to myself. If you want to see the difference, do it yourself.

    Of course not. People do things in the name of "God" all the time, yet it doesn't matter if "God" exists because they did those things regardless. That's entirely off the original point of why powdering was brought up in the first place.

    People "believing" or "feeling" that doesn't make it true.
    Believing and feeling can be what make it true! If you believe that it makes a difference, then to you it does. Whether somebody else believes it or not doesn't change the fact that it changes you. Does a pound make a difference? Can you feel that difference on the trail? Probably not. Does that mean it isn't there? Does knowing that it's a pound lighter make you feel faster? Does that have more of an effect on you than the actual pound? Why do racers feel the need to replace a few steel bolts with aluminum or titanium? Does that 25 grams saved make them more likely to win a race?

    Look, I get what you're saying. Even if there is a difference between powdering a tube and not powdering a tube, it is negligible. What I don't understand is why you are so bent on getting people that can feel a difference to justify it to you. If you need justification, go try it. You don't want anybody else's word on it, anyway.

  67. #67
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    Quote Originally Posted by mountainbiker24 View Post
    I have proven it to myself. If you want to see the difference, do it yourself.
    You think I haven't tried this? I have seen this for myself. I used to be a religious tube powderer. Then I learned something.

    When was the last time you were riding along and noticed something felt wrong, then realized you forgot to powder your tubes? Never. It's ridiculous. You can't claim to feel a difference without accepting this as a reasonable hypothetical.

    You haven't felt a difference because you've never done the test. No one has because it's stupid. People believe they feel a difference because they believe it can make one. It can't, and the moment you realize that you'll lose your religion.

    Quote Originally Posted by mountainbiker24 View Post
    Believing and feeling can be what make it true! If you believe that it makes a difference, then to you it does. ...
    You believe in fairy tales. This is why ostriches stick their heads in the ground. They believe there isn't a threat so there isn't one, right?

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    Quote Originally Posted by craigsj View Post
    You haven't felt a difference because you've never done the test. No one has because it's stupid. People believe they feel a difference because they believe it can make one. It can't, and the moment you realize that you'll lose your religion.


    You believe in fairy tales. This is why ostriches stick their heads in the ground. They believe there isn't a threat so there isn't one, right?
    I have compared a powdered tube to a non-powdered tube. That's a test in my book. I felt a difference. It probably didn't matter at all to the performance of my tire, but there was a difference. As far as believing in fairy tales , threats, and God, well, you got me there. I believe in God. You're the one sticking his head in the sand, however. You refuse to believe in anything just because your "test" failed. That doesn't mean you have proven it false. You just weren't able to prove it true. Since it failed that one time, you've shut yourself off from the possibility that it might be true. You've buried your head in the sand, causing you to miss the point I have been trying to make the whole time.

  69. #69
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    This is getting way too heated for a discussion about the merits of powdered vs unpowdered tubes

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    Quote Originally Posted by mountainbiker24 View Post
    I have compared a powdered tube to a non-powdered tube. That's a test in my book. I felt a difference.
    OK, what was the difference you felt, and why do you think powder causes it?

  71. #71
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    Quote Originally Posted by mountainbiker24 View Post
    You refuse to believe in anything just because your "test" failed. That doesn't mean you have proven it false. You just weren't able to prove it true. Since it failed that one time, you've shut yourself off from the possibility that it might be true. You've buried your head in the sand, causing you to miss the point I have been trying to make the whole time.
    I have not missed your point. You've said repeatedly that believing something is true makes it true. It's hysterical but I got it.

    My "test" didn't "fail" nor is it all I base my statements on. I know that in order for there to be relative movement there needs to be a combination of forces that makes it so. There are not. The tube doesn't slip against the casing because there aren't forces that can make it happen. Without those forces, no lubricant can have an effect. Brandt already said that in the article I quoted earlier. Inconvenient facts get ignored, though. That's the trouble with engineers versus internet engineers.

    There is no arguing with someone who cares more about winning that learning but I'm not trying to convince you, It's more important that others see the folly of your argument. You are a true believer and always will be.

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    So to get back to the original question, I honestly felt that a tubeless tire felt like it conformed to the rooty sections better than a tubed tire does at the same pressure. I also noted that my tires didnt seem to "bounce" off stuff as easily, resulting in a handling improvement, and slightly faster times. So to answer your question, YES I feel as if it does offer handling improvement. In addition, the 12oz it saved in rotating weight also means I have to do les work to accomplish the same goal.

    As for the powdered tubes vs non powdered tubes, I bet nobody here actually uses powder in their wheels. blah blah blah,and I cant even believe you all are arguing it.
    Talcum Powder for Tubes and Tires by Jobst Brandt


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    Quote Originally Posted by craigsj View Post

    "A tube cannot move in a tire when inflated, regardless of what powder is used, because, no translational forces exist, on top of which the holding force between tube and casing is large."

    Go ahead, say Jobst Brandt is wrong because you can "feel" it.
    I just google'd this "Jobst Brandt", and the guy is a wack job in my opinion. Just cause you Google something, and this roadie types it, does not make it true.

    - Pedaling down a flat road, does a tube move inside the tire casing? Hell no, IMO.
    - Booking down a trail with a 2.4 tire at 25psi, and having the tire come a few millimeters from the rim when it impacts a curb-like rock, I believe the tube slips(if free) in the casing a little.

    I'm not more wrong than you are at this point, so unless you can actually prove something, your high-horse is getting a little tired.

    Oh, and, let me ask again. Have you ever removed a tube from a BICYCLE tire, having it be stuck inside the casing?
    Bend, Oregon

  74. #74
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    Quote Originally Posted by craigsj View Post
    I have not missed your point. You've said repeatedly that believing something is true makes it true. It's hysterical but I got it.
    I never said that believing something makes it true. I said that if somebody feels more confident in their equipment, they will push their bike harder. Even if they believe something that isn't necessarily true, they will ride faster if they believe they have an advantage.

    Quote Originally Posted by craigsj View Post
    That's the trouble with engineers versus internet engineers.
    I studied mechanical engineering for 4 years before switching to a career in education. I understand the physics behind this. That's not the point I've been trying to make. Obviously people don't really care about powdered tubes, so I will leave it at that.

  75. #75
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    Quote Originally Posted by thuren View Post
    What if you could theoretically glue 10 tubes inside the tire? They are all soft rubber, but would you agree that might make the tire a bit stiffer to flex?

    If your answer is yes, that means adding only one tube, is stiffer too.
    Sure, it makes it stiffer by the same amount as an un-inflated tube, or basically, not stiffer.

    Quote Originally Posted by thuren View Post
    I just google'd this "Jobst Brandt", and the guy is a wack job in my opinion. Just cause you Google something, and this roadie types it, does not make it true.

    - Pedaling down a flat road, does a tube move inside the tire casing? Hell no, IMO.
    - Booking down a trail with a 2.4 tire at 25psi, and having the tire come a few millimeters from the rim when it impacts a curb-like rock, I believe the tube slips(if free) in the casing a little.

    Oh, and, let me ask again. Have you ever removed a tube from a BICYCLE tire, having it be stuck inside the casing?
    FYI, Jobst Brandt is a mechanical engineer and author of "The Bicycle Wheel". He only looks like a wack job because he goes around dispelling cycling-related myths.\

    I have had an inner tube stick to a tire, but never get permanently stuck. That is the difference between a motorcycle and a bicycle- the bike does not get the tires hot enough that there is a chemical change in the rubber that permanently bonds the inner tube to the tire. This tube sticking should be proof enough to you that an inner tube does not slide around inside a tire once it is inflated. Even on a curb strike, the casing of the tire flexes, but does not stretch (much). The inner tube flexes and stretches along with the casing, so there is no need for any sliding around.

    Quote Originally Posted by mountainbiker24 View Post
    I studied mechanical engineering for 4 years before switching to a career in education. I understand the physics behind this.
    Still waiting for a physics-based explanation of the difference in feel caused by powder.

  76. #76
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    Quote Originally Posted by thuren View Post
    I just google'd this "Jobst Brandt", and the guy is a wack job in my opinion. Just cause you Google something, and this roadie types it, does not make it true.

    - Pedaling down a flat road, does a tube move inside the tire casing? Hell no, IMO.
    - Booking down a trail with a 2.4 tire at 25psi, and having the tire come a few millimeters from the rim when it impacts a curb-like rock, I believe the tube slips(if free) in the casing a little.

    I'm not more wrong than you are at this point, so unless you can actually prove something, your high-horse is getting a little tired.

    Oh, and, let me ask again. Have you ever removed a tube from a BICYCLE tire, having it be stuck inside the casing?
    Doubling down by claiming Jobst Brandt is crazy just proves that you are willfully ignorant. You are free to believe that you are not "more wrong" despite knowing nothing, but don't expect anyone to believe you.

  77. #77
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    Quote Originally Posted by mountainbiker24 View Post
    I never said that believing something makes it true. I said that if somebody feels more confident in their equipment, they will push their bike harder. Even if they believe something that isn't necessarily true, they will ride faster if they believe they have an advantage.
    Post #66:

    "Believing and feeling can be what make it true! If you believe that it makes a difference, then to you it does." - mountainbiker24

    The fallacy here is that in the case that someone makes a change and then believes he is faster, then the change is responsible. Ever heard of the placebo effect? If a rider is faster because he takes more chances, then that's the reason he's faster, not because he made a meaningless change that he thought would help. Believing in something doesn't make it true.

  78. #78
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    Quote Originally Posted by beanbag View Post
    This tube sticking should be proof enough to you that an inner tube does not slide around inside a tire once it is inflated.
    Exactly exactly exactly. Anyone who doesn't get this isn't thinking critically.

    A tube that slides around inside the tire won't get stuck to it, and a tube that doesn't won't perform differently when lubricated. It's so obvious it makes me giggle that people don't get it.

    Regarding the 10-tube thought experiment, 10 tubes may well change a tire's feel. That doesn't mean 1 tube will. There has to be a reason for the difference AND it has to be big enough to matter. I feel no difference with a tube because I use latex and that's a low-loss rubber. When I use butyl it's a thin tube. Heavy butyl tubes will have a greater effect.

  79. #79
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    delete me
    Last edited by noot; 04-07-2012 at 02:13 PM.
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    Quote Originally Posted by craigsj View Post
    There has to be a reason for the difference AND it has to be big enough to matter.
    Reason would be powdered tube, and now you might as well start saying that I think I feel a difference, so it DOES matter haha!

    This thread is awesome!
    Bend, Oregon

  81. #81
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    Quote Originally Posted by noot View Post
    Now this is getting funny enough that I feel like joining

    While I agree that powdering a tube won't make a difference in handling, your statement that "A tube that slides around inside the tire won't get stuck to it" is so full of holes it's not funny.
    So which is it? Funny or not funny?

    How about naming a few of those holes it's full of.

    Quote Originally Posted by noot View Post
    Rather than 10 tubes, imagine ONE tube that's so thick, there's only a 1/4" hole in the middle for air. Stiff? Yes.
    I could be petty and point out this claim is "full of holes" for the things you've failed to say, but I won't. Apparently you feel entitled to a double standard when it comes to rigor. When dealing with people who believe in pixie dust it doesn't pay to be overly pedantic.

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    Quote Originally Posted by craigsj View Post
    Doubling down by claiming Jobst Brandt is crazy just proves that you are willfully ignorant. You are free to believe that you are not "more wrong" despite knowing nothing, but don't expect anyone to believe you.
    Alright then yikes!

    I find it funny, that you factually know, that I know nothing.


    Bend, Oregon

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    Quote Originally Posted by craigsj View Post

    How about naming a few of those holes it's full of.
    How about this. Maybe the tube decided to stick inside the tire, after sitting unused for a couple weeks, but was free inside the casing with constant daily use? Once stuck, it stayed stuck.

    I have to say that while I am typing this, I admit I doubt anyone could EVER tell their tube was stuck in the tire, but I still think having the tube free to move around, DOES make a difference, be it small.
    Bend, Oregon

  84. #84
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    Quote Originally Posted by thuren View Post
    Alright then yikes!

    I find it funny, that you factually know, that I know nothing.


    You have been displaying your intellect here on a public forum.

    Better to remain silent and be thought a fool than to speak out and remove all doubt. - Abraham Lincoln

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    Quote Originally Posted by thuren View Post
    How about this. Maybe the tube decided to stick inside the tire, after sitting unused for a couple weeks, but was free inside the casing with constant daily use? Once stuck, it stayed stuck.
    This was noot's point and I doubt that's what he meant.

    The subject was a tube moving around inside a tire not sticking. If the tube is already stuck it's a different problem.

    Tubes don't bond to casings on their own, there needs to be some external cause. With car and motorcycle tires it was heat. With bicycle tires it is typically moisture and quite commonly the "powder" used to prevent it, ironically enough. I suppose those who always powder their tubes have never experienced removing a tube after 6 months and finding not the least bit of tackiness at all. They are, after all, introducing the agent that proves their preconception.

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    While using my small volume of brain cells today, surely acting ignorant, doing a little work manufacturing some of the products I design and engineer for my company, I came up with a way to possibly test the "tube float in a tire" properties.

    The test set up....

    - New 2.4 Schwalbe Furious Fred. Small knobs and big volume. Sprayed a little simple green inside, cleaned and dried well.
    - Dipped a paintbrush in some talc powder, and brushed the inside of half the tire really well.
    - Cleaned the tube well, and inserted in tire.
    - Marked the rim to show which half was clean, and which half had powder.
    - Inflated to about 28psi.
    - Shimmed under my drill press, holding a digital scale, so that when the press was cranked and maxed out, the tire was deflected by the drill chuck coming down straight on the tread. With the drill press maxed out, this gave a very accurate "stop".
    - The idea is that the powdered side of the tire, will conform to the shape of the drill chuck easier than the non powdered half, making the scale read a lower number.

    Findings... I honestly expected to come away from this with my tail between my legs. After repeating the test MANY times, I came up with an average of about 3lbs lower reading on the powdered side of the tire against the drill chuck.

    After all this, I am still surprised the findings were so consistent.I tried moving around on different knob positions, and really tried to make sure I was NOT cheating the numbers. I may even have someone else work the press, knowing NOTHING about what I am doing. At this point I can say that I did about 30 pulls on the press this evening, and every single time, the pressure readings were lower with the powdered half of the tire, against the drill chuck, mimicking a rock or something on the trail.

    I'll re-test in the AM, and if the results are just as consistent, I will take a video.

    Will also be very easy to bead this tire up tubeless and see how much less pressure reads on the scale.
    Bend, Oregon

  87. #87
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    Measure at 12 evenly spaced points all around the wheel.
    IF this manages to pass, then clean out the tire, powder the other half, and do it again.

    Given your equipment, that seems like a fair measurement.
    No need to get anybody else involved.
    Last edited by beanbag; 04-08-2012 at 02:52 AM.

  88. #88
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    Quote Originally Posted by thuren View Post
    While using my small volume of brain cells today, surely acting ignorant, doing a little work manufacturing some of the products I design and engineer for my company, I came up with a way to possibly test the "tube float in a tire" properties.

    The test set up....

    - New 2.4 Schwalbe Furious Fred. Small knobs and big volume. Sprayed a little simple green inside, cleaned and dried well.
    - Dipped a paintbrush in some talc powder, and brushed the inside of half the tire really well.
    - Cleaned the tube well, and inserted in tire.
    - Marked the rim to show which half was clean, and which half had powder.
    - Inflated to about 28psi.
    - Shimmed under my drill press, holding a digital scale, so that when the press was cranked and maxed out, the tire was deflected by the drill chuck coming down straight on the tread. With the drill press maxed out, this gave a very accurate "stop".
    - The idea is that the powdered side of the tire, will conform to the shape of the drill chuck easier than the non powdered half, making the scale read a lower number.

    Findings... I honestly expected to come away from this with my tail between my legs. After repeating the test MANY times, I came up with an average of about 3lbs lower reading on the powdered side of the tire against the drill chuck.

    After all this, I am still surprised the findings were so consistent.I tried moving around on different knob positions, and really tried to make sure I was NOT cheating the numbers. I may even have someone else work the press, knowing NOTHING about what I am doing. At this point I can say that I did about 30 pulls on the press this evening, and every single time, the pressure readings were lower with the powdered half of the tire, against the drill chuck, mimicking a rock or something on the trail.

    I'll re-test in the AM, and if the results are just as consistent, I will take a video.

    Will also be very easy to bead this tire up tubeless and see how much less pressure reads on the scale.
    So, are you squeezing the tire/wheel between the chuck and the scale, correct? What part of the wheel is resting on the scale?
    15mm is a second-best solution to a problem that was already solved.

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    Quote Originally Posted by kapusta View Post
    So, are you squeezing the tire/wheel between the chuck and the scale, correct? What part of the wheel is resting on the scale?
    Correct. The irregular, lets just say "rock like" shape of the drill chuck, is on the testing side. My thinking is, that the flat scale with the larger surface area, is not going to deflect much or show anything. My argument is that on rough terrain, a powdered tube has an effect.

    Have I ever powdered a bicycle tube? No. But I feel that theoretically is would make a difference off road.


    Quote Originally Posted by beanbag View Post
    Measure at 12 evenly spaced points all around the wheel.
    IF this manages to pass, then clean out the tire, powder the other half, and do it again.

    Given your equipment, that seems like a fair measurement.
    No need to get anybody else involved.
    Being that the powder ending is not a defined line, I might do 6 spots on each side, but closer together, to stay away from the powder termination line.

    Being that slight changes in temperature and pressure, could net different scale figures, I think what I am going for here is inconsistency. If the unpowdered side against the drill chuck constantly reads a couple/few pounds higher on the scale, then with a full powdered tube back in I get withing 1/2lb of so all around, I think that will be a pretty conclusive test.
    Bend, Oregon

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    Quote Originally Posted by thuren View Post
    Correct. The irregular, lets just say "rock like" shape of the drill chuck, is on the testing side. My thinking is, that the flat scale with the larger surface area, is not going to deflect much or show anything. My argument is that on rough terrain, a powdered tube has an effect.
    I think this is an interesting experiment you are doing.

    I do think that in order to draw much conclusion from it, you need to isolate the two sides of the tire being compressed, as what you are currently measuring is the force needed to compress BOTH parts of the tire (the one on the scale and the one against the chuck). I would try to rig it up so that the scale is ultimately pushing against the hub or the rim (under where the chuck is).

    Also, I would repeat this with the tire powdered on the other half.

    These two things together would eliminate all the most obvious alternative explanations.
    15mm is a second-best solution to a problem that was already solved.

  91. #91
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    Quote Originally Posted by thuren View Post
    Being that the powder ending is not a defined line, I might do 6 spots on each side, but closer together, to stay away from the powder termination line.

    Being that slight changes in temperature and pressure, could net different scale figures, I think what I am going for here is inconsistency. If the unpowdered side against the drill chuck constantly reads a couple/few pounds higher on the scale, then with a full powdered tube back in I get withing 1/2lb of so all around, I think that will be a pretty conclusive test.
    U should have the measurement points spaced far apart to eliminate systematic errors like a high spot in the tire. Also, u need to have the measurement points cross over the powder line to show that it actually made a difference.

    Then u need to switch powdered sides and get exactly the opposite result.

    Otherwise you are just measuring an egg shaped tire.

  92. #92
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    A static test cannot measure a contributions due to hysteresis, not that I take this "test" seriously. It's a fool's errand to save face.

    If this does theoretically make a difference "off road", then the theory should be clearly enunciated along with an explanation for how the testing can confirm or reject the theory. Also, "3 pounds" is meaningless without context. Is it 3 pounds out of 5 or 500? Like so often occurs on MTBR, no consideration is given to the significance of the effect. Engineers don't make that mistake. Engineering requires understanding of what is important and what is not.

    There are other issues beside what others have mentioned already, most notably no effort made to ensure that the tube has reached a final, stable position in the casing before measurement. This test, though, is designed to win an argument, not to actually prove anything. If powder were to actually work by reducing friction, this test could not demonstrate it since it is static. If it were to work by eliminating stiction, then the test fails in its setup.

  93. #93
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    Quote Originally Posted by craigsj View Post
    Post #66:

    "Believing and feeling can be what make it true! If you believe that it makes a difference, then to you it does." - mountainbiker24

    The fallacy here is that in the case that someone makes a change and then believes he is faster, then the change is responsible. Ever heard of the placebo effect? If a rider is faster because he takes more chances, then that's the reason he's faster, not because he made a meaningless change that he thought would help. Believing in something doesn't make it true.
    How dense are you? I have said over and over that it isn't the actual change that makes the difference. It's the perception of the rider to the change that makes the difference. Reading comprehension, son.

  94. #94
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    Quote Originally Posted by mountainbiker24 View Post
    How dense are you? I have said over and over that it isn't the actual change that makes the difference. It's the perception of the rider to the change that makes the difference. Reading comprehension, son.
    So you said "Believing and feeling can be what make it true!", then turned around and said "I never said that believing something makes it true." Now you are blaming my "reading comprehension"?

    Give it up. You just look more stupid.

  95. #95
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    Quote Originally Posted by craigsj View Post
    A static test cannot measure a contributions due to hysteresis, not that I take this "test" seriously. It's a fool's errand to save face.
    You my friend, are pretty freaking rude. You are so committed now, quoting Mr Jobst Brandt, I don't think there is any test you would feel good accepting. Let me ask you this. Did mr Brandt do any tests at all? He claims there is no translational forces, and on a smooth tire I pretty much agree. On a knobby off road tire, when the knobs fold in and the tire casing reverses, damn straight there is some translational forces being attempted. I don't think this test I am doing, is in ANY way acceptable under any even remotely professional arena, but it is enough to get a somewhat reliable clue. I have better things to do, so I am not going to start testing different tires, testing the casing durometer/thickness, and so on.

    If this does theoretically make a difference "off road", then the theory should be clearly enunciated along with an explanation for how the testing can confirm or reject the theory. Also, "3 pounds" is meaningless without context. Is it 3 pounds out of 5 or 500? Like so often occurs on MTBR, no consideration is given to the significance of the effect. Engineers don't make that mistake. Engineering requires understanding of what is important and what is not.
    I agree thank you for HELPING the discussion. About 3 lbs average, in the 190lb or so reading on the scale. As noted, I'm not going for claiming this theory fact, just trying to open up the minds of some people. If I am wrong, I am wrong, and I have NO problem accepting that. I can only hope others are as open, as Jobst Brandt claiming there is no effect, is not that reliable in my eyes. Maybe he DID do some tests and I am ignorant to that, but I can't tell you how many things I have had to re-engineer over my career. Just because something has been run through by one engineer, does not make it truth, let alone a mere claim.

    There are other issues beside what others have mentioned already, most notably no effort made to ensure that the tube has reached a final, stable position in the casing before measurement. This test, though, is designed to win an argument, not to actually prove anything. If powder were to actually work by reducing friction, this test could not demonstrate it since it is static. If it were to work by eliminating stiction, then the test fails in its setup.
    I agree that there are SO many factors, and mentioned a few above, that can play into this situation. I am not claiming to have all bases covered. But, coming out of this with a consistent difference, is something to build upon. I don't care how MUCH difference there is, just that there is a difference. At least it IS somewhat of a test, instead of a notion in an educated persons mind.

    I just did some more runs on the tire, trying to make sure I hit the matching spot on the tread so it flexed the same, and zeroing out the scale every time. Same result as yesterday.
    Bend, Oregon

  96. #96
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    Quote Originally Posted by thuren View Post
    You my friend, are pretty freaking rude. You are so committed now, quoting Mr Jobst Brandt, I don't think there is any test you would feel good accepting. Let me ask you this. Did mr Brandt do any tests at all?
    Attacking Jobst Brandt says more about you than Jobst Brandt.

    Quote Originally Posted by thuren View Post
    He claims there is no translational forces, and on a smooth tire I pretty much agree. On a knobby off road tire, when the knobs fold in and the tire casing reverses, damn straight there is some translational forces being attempted.
    I might have to frame that. This is what Abraham Lincoln was talking about.

    Quote Originally Posted by thuren View Post
    ... I'm not going for claiming this theory fact, just trying to open up the minds of some people. If I am wrong, I am wrong, and I have NO problem accepting that. I can only hope others are as open, as Jobst Brandt claiming there is no effect, is not that reliable in my eyes.
    No, you have a big problem accepting that.

    You should look a little more into Brandt's technical understanding of cycling issues. I'm curious, how does your drill press test duplicate the process of creating those translational forces you claim occur above? Before answering, you need to understand what Brandt actually meant. All the external forces acting on the tube are normal to its surface. If that doesn't make sense to you, think about it. It's the part you are missing. Prove there are more forces than that and you disprove Brandt's claim.

    Quote Originally Posted by thuren View Post
    ...I am not claiming to have all bases covered. But, coming out of this with a consistent difference, is something to build upon. I don't care how MUCH difference there is, just that there is a difference. At least it IS somewhat of a test, instead of a notion in an educated persons mind.
    and here you have failed. It's not something to "build upon" until you can rule out unrelated explanations for the result AND explain how the data relates to your theory. You can't even present a cogent theory for how it could do what you claim.

    Quote Originally Posted by thuren View Post
    I just did some more runs on the tire, trying to make sure I hit the matching spot on the tread so it flexed the same, and zeroing out the scale every time. Same result as yesterday.
    And I duplicated your test and got no difference whatsoever.

    Saying "I have a number" doesn't mean anything. People quote impossible results all the time. It's the internet.

    As I say here often, I'm not trying to convince you because you care about winning, not learning. BTW, it is unlikely that anyone could ever notice a tire spring rate change of only 1.5% (3/190). If you don't believe that, look into just noticeable differences. People who pretend to be engineers often fail to get this. It's not that I accept that you've measured a difference, I don't, it's just that difference of that magnitude wouldn't matter even if it did exist. It's far more likely that 1.5% is within the range of error in your measurement, a problem others have hinted at due to your sloppy methodology.

    Science isn't poking around until you find what you want.

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    Quote Originally Posted by craigsj View Post
    No, you have a big problem accepting that.

    You should look a little more into Brandt's technical understanding of cycling issues. I'm curious, how does your drill press test duplicate the process of creating those translational forces you claim occur above? Before answering, you need to understand what Brandt actually meant. All the external forces acting on the tube are normal to its surface. If that doesn't make sense to you, think about it. It's the part you are missing. Prove there are more forces than that and you disprove Brandt's claim.
    How about we just focus on this, as it seems to me that if there can be acceptance there are some translational forces, we can be done here? What he is saying makes perfect sense to me. I'm saying that I think otherwise.

    I have a way to explain it, but I think I have a better way to illustrate it. Let me try something real quick.
    Bend, Oregon

  98. #98
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    Quote Originally Posted by thuren View Post
    How about we just focus on this, as it seems to me that if there can be acceptance there are some translational forces, we can be done here? What he is saying makes perfect sense to me. I'm saying that I think otherwise.

    I have a way to explain it, but I think I have a better way to illustrate it. Let me try something real quick.
    Movement between the tube and tire requires a combination of forces capable of it. The Brandt argument is that there can be no such forces, so if powdering matters you must disprove that at very minimum. There would be some additional arguments needed, but that's the biggest one to overcome. My personal opinion is that addressing that is more productive than trying to do testing without a working theory. Even with positive test results, you end up left to do follow up testing to rule out other possible explanations.

    I believe this is a difficult argument to make, though, and I don't mean that personally.

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    So the translational forces seen here, under compression and extension of the material, would not happen if the surfaces were stuck together. Surely this is exaggerated, but the surfaces sliding over each other can be seen, as each surface line takes on a trapezoidal shape. Possible this happens with a tube and tire, when absorbing impact?
    Attached Thumbnails Attached Thumbnails Tubeless = Handling improvement?-demo.jpg  

    Last edited by thuren; 04-08-2012 at 02:27 PM.
    Bend, Oregon

  100. #100
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    I don't know what's being shown here. Please explain. Also, when you say there are "translational forces" seen here, what are you referring to?

    It appears the tire is bottoming out in the drill press photo. This would be an abnormal condition on a ride.

  101. #101
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    Quote Originally Posted by thuren View Post
    So the translational forces seen here, under compression and extension of the material, would not happen if the surfaces were stuck together. Surely this is exaggerated, but the surfaces sliding over each other can be seen, as each surface line takes on a trapezoidal shape. Possible this happens with a tube and tire, when absorbing impact?
    I don't know what you just showed, but the answer is NO anyways.
    Translational forces happen between two surfaces when one of them changes shape within the surface only, such as stretch or shear, and the other surface has to keep up. Translational forces don't arise from bending only - that would be a normal force.

    As I keep on saying over and over again, an inner tube is stretchy but a tire casing is not. The inside surface of a tire bends but does not stretch or shear (by much). An inner tube bends and does stretch, to make up for even tiny amounts of tire stretch, and thus it can follow the surface of the tire without slipping. The very tiny amount of translational force is totally overwhelmed by the frictional holding force of 28 psi mashing the tube into the tire times the friction coefficient, even if there is powder present.

    The only times when there is tube slipping is

    When you initially pre-inflate a tire to something like 5 psi and give it that little massage. (I'm not the only one that does this, right?) All that creaking and squeaking is the tube settling in to a final position. The clamping force at 5psi is not very large so the tube can slip around.

    When you pinch flat and mash the inside of the tube surface against something else.
    Last edited by beanbag; 04-08-2012 at 03:16 PM.

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    Had to run out the door posted that kinda quick.

    Tire is not close to bottoming out. That would be a very normal condition of a tire. 30psi, and 197lbs force to do that.

    Top surface would be tire, bottom surface tube.
    Bend, Oregon

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    If the tube deflects, it heats up. Thats loss. More heat, more loss. Old school days ( 50 years ago or so) all auto tubes were powdered. One reason as it helped the tube to find its happy spot inside the tire. Now, does this scrubbing of a powdered tube against the inside raise the operating temp? Or does the increased tube deflection from a dry tube heat up the tube more?

    I will say my own little BS test of tubeless proved to me, and thats all that counts, that tubeless rolls easier with my fat ass. I think the powder was to keep the less than ideal rubber compounds of the day lasting longer inside an auto tire. As in wearing and tearing. Also the old auto tires can work its way around the rim, so the powder allowed the tire to slip against the tube.
    lean forward

  104. #104
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    Quote Originally Posted by beanbag View Post
    I don't know what you just showed, but the answer is NO anyways.
    Translational forces happen between two surfaces when one of them changes shape within the surface only, such as stretch or shear, and the other surface has to keep up. Translational forces don't arise from bending only - that would be a normal force.

    As I keep on saying over and over again, an inner tube is stretchy but a tire casing is not. The inside surface of a tire bends but does not stretch or shear (by much). An inner tube bends and does stretch, to make up for even tiny amounts of tire stretch, and thus it can follow the surface of the tire without slipping. The very tiny amount of translational force is totally overwhelmed by the frictional holding force of 28 psi mashing the tube into the tire times the friction coefficient, even if there is powder present.

    The only times when there is tube slipping is

    When you initially pre-inflate a tire to something like 5 psi and give it that little massage. (I'm not the only one that does this, right?) All that creaking and squeaking is the tube settling in to a final position. The clamping force at 5psi is not very large so the tube can slip around.

    When you pinch flat and mash the inside of the tube surface against something else.
    28psi mashing the tube? It would be no harder to push the tube off the surface of the inner tire, as it would to push on a 28psi tire and deflect it with your thumb, which is not hard.

    Some of you in this thread are KILLING me with you finite factual attitude.
    Bend, Oregon

  105. #105
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    Quote Originally Posted by beanbag View Post
    The inside surface of a tire bends but does not stretch or shear (by much). An inner tube bends and does stretch, to make up for even tiny amounts of tire stretch, and thus it can follow the surface of the tire without slipping.
    Yeah I get what you are saying, and understand the theory. How about if you had a high TPI stretchy tire(they do stretch more than you imply), and a HD tube?

    How can you PROVE that the tube is not a little more happy, being able to deform and slide instead of stretch?
    Bend, Oregon

  106. #106
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    Quote Originally Posted by 1niceride View Post
    If the tube deflects, it heats up. Thats loss.
    A latex tube doesn't.

    Quote Originally Posted by 1niceride View Post
    Now, does this scrubbing of a powdered tube against the inside raise the operating temp?
    There is no scrubbing of a powdered tube against the tire.

    Quote Originally Posted by 1niceride View Post
    Or does the increased tube deflection from a dry tube heat up the tube more?
    Powdering the tube was not to reduce heating of the tube.

    Quote Originally Posted by 1niceride View Post
    Also the old auto tires can work its way around the rim, so the powder allowed the tire to slip against the tube.
    That would be a failure situation. Occasionally a bike tire/rim combination does this too. The result is a failed valve stem.

  107. #107
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    Quote Originally Posted by thuren View Post
    28psi mashing the tube? It would be no harder to push the tube off the surface of the inner tire, as it would to push on a 28psi tire and deflect it with your thumb, which is not hard.
    .
    This analogy is wrong because you are confusing a force with a spring rate, which is force divided by distance.

    28 lbs per square inch is the force required to lift (a sq inch) of inner tube off the tire. Before that point, nothing happens. Far less than 28 lbs is required to deflect an inflated tire.

    Hey, the front springs on my car are 400 lbs/in, or a total of 800 lbs/in. Yet I can press down my front bumper with only 100 lbs. Why?!?!?!?

  108. #108
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    Quote Originally Posted by thuren View Post
    How can you PROVE that the tube is not a little more happy, being able to deform and slide instead of stretch?
    The tube only has to conform to the inside of the casing and the casing doesn't stretch as it deforms with rolling. Again, this question supposes that there are forces that encourage a sliding between the tube and tire. That cannot be assumed.

    I still don't understand what you are trying to say with those pictures.

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    All this seems like searching for one piece of fly poop in a pound of pepper.

    Its all about heat. Follow the heat...
    lean forward

  110. #110
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    Quote Originally Posted by thuren View Post
    Yeah I get what you are saying, and understand the theory. How about if you had a high TPI stretchy tire(they do stretch more than you imply), and a HD tube?

    How can you PROVE that the tube is not a little more happy, being able to deform and slide instead of stretch?
    A high TPI tire only feels stretchy because in the un-inflated form, the fibers are more free to flop around. If you REALLY want to know how much a tire stretches, measure its width when inflated at 20 psi and 30 psi. Now calculate the hoop stress at these two pressures. This will tell you the elasticity of a tire casing under normal operating conditions. Now compare that to an inner tube. OR, an easier, math adverse, way is to inflate a bare inner tube to the same sizes and measure the pressure differences in the tube. This will tell you the relative differences in stretch between a tube and a tire.

    As for "being happy", sure, a tube would rather slide around in order to minimize its internal stresses. But we can't always get what we want to make us happy. (A valuable life lesson indeed). It has to overcome the clamping force first. 28psi is stepping on a sheet of rubber with the heel of one foot only. You can put some powder on if you like. I don't think that sheet of rubber is going anywhere.

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    Quote Originally Posted by thuren View Post
    Yeah I get what you are saying, and understand the theory. How about if you had a high TPI stretchy tire(they do stretch more than you imply), and a HD tube?

    How can you PROVE that the tube is not a little more happy, being able to deform and slide instead of stretch?
    The proof is in the heat rise or lack of it. All this was quantified 50 or 60 years ago with auto tires. It is a thermodynamic issue.
    lean forward

  112. #112
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    Quote Originally Posted by 1niceride View Post
    The proof is in the heat rise or lack of it. All this was quantified 50 or 60 years ago with auto tires. It is a thermodynamic issue.
    The problem with car tires is heat, but it's not heat originating in a tube. The tire casing heats up as it rolls; thats why car tires, tubeless as they are today, have speed ratings. Bicycle tires heat up too, to a lesser extent, but not because they have tubes in them.

  113. #113
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    4 equivalent wheels, 1 ghetto setup (non ust set up tublesss); 1 ust; 1 tube powdered; 1 tube dry.
    Run on treadmill 1 hour.
    Shoot with infrared gun to check temp rise.
    Which will heat up less? My bet is on the ghetto setup.
    lean forward

  114. #114
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    Quote Originally Posted by craigsj View Post
    The problem with car tires is heat, but it's not heat originating in a tube. The tire casing heats up as it rolls; thats why car tires, tubeless as they are today, have speed ratings. Bicycle tires heat up too, to a lesser extent, but not because they have tubes in them.
    You must be a politician...
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  115. #115
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    Quote Originally Posted by craigsj View Post
    The tube only has to conform to the inside of the casing and the casing doesn't stretch as it deforms with rolling. Again, this question supposes that there are forces that encourage a sliding between the tube and tire. That cannot be assumed.

    I still don't understand what you are trying to say with those pictures.
    When you have two layers pressed together, and you bend them, if they are not attached, they will slide against each other. If they cannot slide against eachother, then one will need to stretch and the other compress, and this will make it harder to bend.

    For example: Take a bunch of pages in a book and bend them. you will notice that at the edges of the pages, they have slid against each other. Now, pinch the pages so they cannot slide against each other, and try to bend them again. It will be much harder.

    Another example: Take two sheets of steel (or plastic, or wood)that are 1/16" thick and stack them together and try to bend them. Then try this with a single 1/8" sheet (which is like 2 1/16" sheets bonded). The 1/8" will be harder to bend.

    Now with a tire casing and tube, one of those layers (the tube) stretches and compresses very easily, so the effects are minimized, but it does make sense that it would take more force to deform the casing and tube a given amount if they are bonded. Whether that effect is in any way significant is another question, and personally, I am doubtful.
    15mm is a second-best solution to a problem that was already solved.

  116. #116
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    Quote Originally Posted by kapusta View Post

    Another example: Take two sheets of steel (or plastic, or wood)that are 1/16" thick and stack them together and try to bend them. Then try this with a single 1/8" sheet (which is like 2 1/16" sheets bonded). The 1/8" will be harder to bend.
    And will show up as heat as more material is being deflected. Its all about heat. Heat that doesn't push is loss.
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  117. #117
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    Quote Originally Posted by 1niceride View Post
    You must be a politician...
    You are spending a lot of posts saying repeatedly "the problem is heat". What "problem" are you talking about?

  118. #118
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    Accually, the topic is about handling, not about rolliing resistance. My bad...
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  119. #119
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    Quote Originally Posted by kapusta View Post
    When you have two layers pressed together, and you bend them, if they are not attached, they will slide against each other.
    Not necessarily. Attach them at both ends and bend in the middle. Make the layers concentric circles, the inner one elastic, and inflate the inner one to press on the outer one. Bend anywhere.

    Quote Originally Posted by kapusta View Post
    For example: Take a bunch of pages in a book and bend them. you will notice that at the edges of the pages, they have slid against each other.
    They are not constrained on both ends like a tire/tube will be.

    Quote Originally Posted by kapusta View Post
    Now, pinch the pages so they cannot slide against each other, and try to bend them again. It will be much harder.
    The pages are inelastic, unlike the tube.

    Quote Originally Posted by kapusta View Post
    Now with a tire casing and tube, one of those layers (the tube) stretches and compresses very easily, so the effects are minimized, but it does make sense that it would take more force to deform the casing and tube a given amount if they are bonded. Whether that effect is in any way significant is another question, and personally, I am doubtful.
    I am also doubtful, even to the the extent that I say it doesn't even make sense. You are right, though, there needs to be both a case for how it could occur AND and understanding of how significant the result would be.

    A tube and tire will not bond even without powder to prevent it. The external conditions aren't present for that to happen. If, say, we added some rubber cement, then they would. Doing so may well increase deformation losses, but not because the tube has become constrained.

    As a practical matter, the rolling resistance contribution of a butyl tube is an order of magnitude lower than that of the tire. Any effect of this nature would be another order of magnitude lower than that...at the very greatest. Two orders of magnitude is too small a change to be noticable in cases like this. Whether it exists at all is strictly academic; we are talking about fractions of a watt if it exists at all.

  120. #120
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    Quote Originally Posted by 1niceride View Post
    Accually, the topic is about handling, not about rolliing resistance. My bad...
    OK. The reason it seemed I was being pedantic with you earlier is that we were talking about different things. When it comes to rolling resistance, heat does tell the story.

  121. #121
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    Quote Originally Posted by craigsj View Post
    Not necessarily. Attach them at both ends and bend in the middle. Make the layers concentric circles, the inner one elastic, and inflate the inner one to press on the outer one. Bend anywhere.


    They are not constrained on both ends like a tire/tube will be.


    The pages are inelastic, unlike the tube.


    I am also doubtful, even to the the extent that I say it doesn't even make sense. You are right, though, there needs to be both a case for how it could occur AND and understanding of how significant the result would be.

    A tube and tire will not bond even without powder to prevent it. The external conditions aren't present for that to happen. If, say, we added some rubber cement, then they would. Doing so may well increase deformation losses, but not because the tube has become constrained.

    As a practical matter, the rolling resistance contribution of a butyl tube is an order of magnitude lower than that of the tire. Any effect of this nature would be another order of magnitude lower than that...at the very greatest. Two orders of magnitude is too small a change to be noticable in cases like this. Whether it exists at all is strictly academic; we are talking about fractions of a watt if it exists at all.
    There is just too much confusion and mis-application of principle in this post to even begin to address all of it. I'm not interested in wasting time arguing with someone who simply wants to argue for argument's sake. There are aspects to this discussion you seem a bit off on, it is up to you whether you want to understand what they are. Or not, it's up to you, I really don't care.
    15mm is a second-best solution to a problem that was already solved.

  122. #122
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    Quote Originally Posted by kapusta View Post
    There is just too much confusion and mis-application of principle in this post to even begin to address all of it. I'm not interested in wasting time arguing with someone who simply wants to argue for argument's sake. There are aspects to this discussion you seem a bit off on, it is up to you whether you want to understand what they are. Or not, it's up to you, I really don't care.
    Haha.

  123. #123
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    Quote Originally Posted by beanbag View Post
    Hey, the front springs on my car are 400 lbs/in, or a total of 800 lbs/in. Yet I can press down my front bumper with only 100 lbs. Why?!?!?!?
    I'm staring at 5 pallets of coil springs, I designed, so I guess you could say I understand. This is just getting stupid now. I wasted too much time on this thread already I run tubeless anyway lol!
    Bend, Oregon

  124. #124
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    Quote Originally Posted by thuren View Post
    I'm staring at 5 pallets of coil springs, I designed, so I guess you could say I understand. This is just getting stupid now. I wasted too much time on this thread already I run tubeless anyway lol!
    Haha.

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