1. The most important thing about buying a new bike is to make sure it fits. The only way you'll know if the bike is right for you is to size up the bike and make sure that the bike's geometry matches your body's geometry. Ask questions and do some research.
mtn. biking 101
2. If possible, try to find a shop that will let you demo the bike on real dirt. Five minutes in a parking lot won't cut it. You wouldn't buy a car without a real world test drive, and a bike should be no different.
3. Don't belive the hype. Just because your favorite rider or best friend rides a certain bike, that doesn't mean that's the best one for you. Have an open mind and be realistic about your needs and ability.
Page 3 of 6 FirstFirst 1 2 3 4 5 6 LastLast
Results 51 to 75 of 127
  1. #51
    banned
    Reputation:
    Join Date
    Sep 2012
    Posts
    1,510
    Quote Originally Posted by TiGeo View Post
    I can't believe all the back and forth about rolling resistance and the theory of it. Stop reading this crap, convert them to tubeless, run lower pressure than your are used to, and go for a ride. Then you can make your own opinion of whether or not you think it works. This reminds of me of all the theorizing that goes on about 29ers, whether they roll over things easier, whether they climb easier, whether they are faster, blah blah blah. Just buy one and ride it. If you like it, great, if you don't, sell it and go back to your 26er.
    Thank goodness. It does look like we are over analyzing this.

    -S

  2. #52
    Cow Clicker
    Reputation: wmac's Avatar
    Join Date
    Sep 2010
    Posts
    2,349
    No, YOU don't understand. You're making an ass of yourself for all of eternity.

  3. #53
    mtbr member
    Reputation:
    Join Date
    Sep 2012
    Posts
    60
    Quote Originally Posted by Bill in Houston View Post
    you're already going from 8speed to 10speed for reasons that make sense only to you. why ask us about tubeless?

    sounds like you are a guy with some money to spend who likes to have nice stuff, even if he doesn't necessarily know why. all the guys like you have tubeless. all of them say it is way superior to tubes, even though they can't exactly explain why.

    it sounds like other people do all the work on your bike, so that is something in favor of getting tubeless - if you don't have to do the work yourself and have the money, why not get it?

    i hope it doesn't sound like i'm raining on your parade. i guess i'm just saying that only you can decide, and a lot of guys like you have gone to tubeless. whichever way you go, i hope you are happy and get to ride it plenty.
    I'm going from 8 to 10 because I got a screaming deal on parts. And actually I did all the upgrades myself.

    After reading all the feedback, I'm thinking just sticking my my current setup and run tubes. The extra money for a tubeless set up doesn't seam to make since. Thanks for all the feedback guys!


    Sent from my iPad using Tapatalk HD

  4. #54
    CSC
    CSC is offline
    mtbr member
    Reputation:
    Join Date
    May 2011
    Posts
    255
    comment deleted

  5. #55
    mtbr member
    Reputation:
    Join Date
    Oct 2011
    Posts
    452
    Quote Originally Posted by Saul Lumikko View Post
    Increased traction doesn't necessarily mean increased rolling resistance. Traction stops the tire from slipping, but rolling is a different thing.

    When going over irregularities, a tire without a tube will conform to the changes more easily, so it's more noticeable than on hard and smooth surface.

    006_007, my observation could be placebo, because if the effect was as big as I perceive, it should be easily replicated in an empirical test. However, I think if you rolled as far with a tubeless setup - which is lighter and thus has less freewheeling effect - you already witnessed a lower rolling resistance. (Whether this can be noticed when riding is a different thing entirely.)
    I recently converted my cross bike to tubeless running 700x40 touring tires.
    - DSCF1446

    I found that indeed I had more traction and less rolling resistance at the same time. I no longer slip on the same gravel road climb that I used to w/ tubes when standing and pumping he pedals hard. Likewise I have seen like 1 - 1.5 MPH faster rolling speed on a couple of test rides on the same roads. I can feel it is easier to pedal for the same speed on pavement and this is with running 28psi tubeless compared to 35-40 w/ tubes. I had been running a pretty heavy tube in the tires. And this is with the exact same tires tubes and tubeless.

    Hardest thing I have found so far is fighting that old urge to "pump those tires up", I am used to 50-70psi in my touring bike and 90-100psi on my road bike.
    Last edited by 4Crawler; 11-18-2012 at 08:53 AM.

  6. #56
    Cow Clicker
    Reputation: wmac's Avatar
    Join Date
    Sep 2010
    Posts
    2,349
    Quote Originally Posted by CSC View Post
    comment deleted
    Why delete? We all saw it. It was good.
    No, YOU don't understand. You're making an ass of yourself for all of eternity.

  7. #57
    CSC
    CSC is offline
    mtbr member
    Reputation:
    Join Date
    May 2011
    Posts
    255
    Quote Originally Posted by 4Crawler View Post
    I recently converted my cross bike to tubeless running 700x40 touring tires.
    - DSCF1446

    I found that indeed I had more traction and less rolling resistance at the same time. I no longer slip on the same gravel road climb that I used to w/ tubes when standing and pumping he pedals hard. Likewise I have seen like 1 - 1.5 MPH faster rolling speed on a couple of test rides on the same roads. I can feel it is easier to pedal for the same speed on pavement and this is with running 28psi tubeless compared to 35-40 w/ tubes. I had been running a pretty heavy tube in the tires.

    Hardest thing I have found so far is fighting that old urge to "pump those tires up", I am used to 50-70psi in my touring bike and 90-100psi on my road bike.
    Not relevant data unless you used the same tires. Lighter tires with a new tread pattern with no tubes, and a bit of the good old placebo effect will do wonders for climbs.


    And wmac...I deemed the conversation closed, as the OP made a choice (as it turns out my comment was correct...I just thought it was a little useless to have it up after OP said effectively the same thing).
    Last edited by CSC; 11-18-2012 at 12:01 AM.

  8. #58
    mtbr member
    Reputation: TiGeo's Avatar
    Join Date
    Jul 2008
    Posts
    4,019
    Note that my post could be used to solve:

    wide vs. narrow handlebar threads
    mechanical vs. hydro brake threads
    FS vs. HT threads
    650b vs. 29er (any wheel size) threads

    The list could go on and on!
    Geologist by trade...bicycle mechanic (former) by the grace of God!

    2012 Specialized Stumpy EVO 29 HT

  9. #59
    Cow Clicker
    Reputation: wmac's Avatar
    Join Date
    Sep 2010
    Posts
    2,349
    Hey TiGeo: There is an "Unsubscribe" button, you know.
    No, YOU don't understand. You're making an ass of yourself for all of eternity.

  10. #60
    mtbr member
    Reputation: Saul Lumikko's Avatar
    Join Date
    Oct 2012
    Posts
    1,381
    Quote Originally Posted by CSC View Post
    A flat tire on or off road does increase rolling resistance. I guarantee it.
    Of course it does. I don't think anyone in this thread disagrees.

    Quote Originally Posted by CSC View Post
    A flattened mud tire may be faster at getting through mud than a pumped up tire, but it still has more rolling resistance than when inflated to its "Goldilocks" psi.
    Well, "flattened" is a relative term. If by "Goldilocks" you mean optimum pressure, then I agree - and it will be faster too.

    Quote Originally Posted by wmac View Post
    CSC, you are right. Rolling resistance is rolling resistance. The terrain doesn't magically change the rolling resistance physics. Running lower pressure is higher rolling resistance regardless of the terrain. The same bike with the same rider with the same tires is going to have lower rolling resistance at 40 psi vs 25 psi regardless of terrain. The difference is the energy expended to make it from point a to point b on various terrain with 40 psi vs 25 psi. Running lower tire pressures is an argument of efficiency, not rolling resistance.
    As someone who rides on streets and roads and off-road trails, I could not disagree more strongly. Rolling resistance happens between the tire and surface, and both of these have an equal part in the whole equation.

    If we push a bike on a smooth polished surface, maybe glass, we'll indeed get the lowest resistance with the tire pumped as hard as it can take.
    Step out to the real world to as much as pavement, and you'll notice vibration with the bike set up for a glass surface. Reduce the pressure a bit to make the tire conform to the irregularities and the rolling resistance will be reduced as well.
    Asphalt in a bad condition requires again a slight drop in pressure to optimize rolling resistance.
    When riding on a trail with rocks, roots and other bumps, lowering the pressure even further will reduce rolling resistance.

    Of course one could ask the question "lower than what?", and it's a good question. The "lower your pressures for rougher conditions" is not a suggestion to go below the optimum pressure, but find the optimum one. Higher for harder and smoother surfaces, lower for bumpier and softer conditions.

    Quote Originally Posted by CSC View Post
    I mean, no one would run 15 psi tubeless, right?
    Been there, done that. It increased the rolling resistance a bit, while traction only got better. Depends on a few things - I weigh 72 kg (158 pounds) and have 21 mm (inside width) rims with 2.35 29er tires.

    Do note that I'm not saying people should run lower pressures, but instead find the right one for their weight, tires, trail and riding style. In some cases lowering the pressure will reduce rolling resistance, but going too far will make it increase again.

  11. #61
    mtbr member
    Reputation: TiGeo's Avatar
    Join Date
    Jul 2008
    Posts
    4,019
    I can't help it.
    Geologist by trade...bicycle mechanic (former) by the grace of God!

    2012 Specialized Stumpy EVO 29 HT

  12. #62
    Cow Clicker
    Reputation: wmac's Avatar
    Join Date
    Sep 2010
    Posts
    2,349
    "Rolling resistance is the energy that is lost when the tire is rolling and the main reason for loss of energy is the constant deformation of the tire."

    Source: Rolling Resistance | Schwalbe North America
    No, YOU don't understand. You're making an ass of yourself for all of eternity.

  13. #63
    mtbr member
    Reputation: 006_007's Avatar
    Join Date
    Jan 2004
    Posts
    8,256
    Quote Originally Posted by swcreates View Post
    I'm doing some upgrades to my bike, and I'm looking my options for wheels. I'm to the point know where I'm looking at tube and tubeless rims. What would be the main reason for going tubeless?

    I'm sure it's a simple answer, but this noob needs some help.

    Dayum, so much for a simple answer. 3 pages rambling on about rolling resistance VS pressures. At least there were no charts involved. Charts are bad. Unless its a pie chart. Pie is good.

    OP please do not hesitate to post again in the future. We have pie.


  14. #64
    sock puppet
    Reputation: osokolo's Avatar
    Join Date
    Jan 2004
    Posts
    8,526
    Quote Originally Posted by wmac View Post
    The same bike with the same rider with the same tires is going to have lower rolling resistance at 40 psi vs 25 psi regardless of terrain. The difference is the energy expended to make it from point a to point b on various terrain with 40 psi vs 25 psi. Running lower tire pressures is an argument of efficiency, not rolling resistance.
    this is what matters... rolling resistance is often used in the same sentence with average speed and traction.

    lower pressure tires may have higher rolling resistance (dependent on the design and thread - in some cases the difference is INSIGNIFICANT) but in most cases - off road - lower resistance means higher average speed OR less energy required to cover the distance between point A and point B.

    lower pressure tires better conform to the rough nature of off road trails where the rubber requires less energy to absorb the roughness as opposed to the rest of the bike - suspension, frame, seat post, handlebar etc...

    always added benefit is traction - which increases with softer tires.

    about the only negative side is messy setup (non ust) and often tire changes - which i addressed by owning 2-3 sets of wheels - to address different riding/racing conditions (mostly racing). if you do not change tires often - this negative side may be easily ignored.

    tubeless setup, in my case, is superior to tubed - for above mentioned reasons.

  15. #65
    sock puppet
    Reputation: osokolo's Avatar
    Join Date
    Jan 2004
    Posts
    8,526
    Quote Originally Posted by TiGeo View Post
    I can't help it.
    what is wrong in learning from other people's experiences and mistakes...

    saved me a lot of money...

  16. #66
    CSC
    CSC is offline
    mtbr member
    Reputation:
    Join Date
    May 2011
    Posts
    255
    Quote Originally Posted by Saul Lumikko View Post
    Of course it does. I don't think anyone in this thread disagrees.


    Well, "flattened" is a relative term. If by "Goldilocks" you mean optimum pressure, then I agree - and it will be faster too.

    Of course one could ask the question "lower than what?", and it's a good question. The "lower your pressures for rougher conditions" is not a suggestion to go below the optimum pressure, but find the optimum one. Higher for harder and smoother surfaces, lower for bumpier and softer conditions.


    Do note that I'm not saying people should run lower pressures, but instead find the right one for their weight, tires, trail and riding style. In some cases lowering the pressure will reduce rolling resistance, but going too far will make it increase again.
    Which is why I keep referencing the tire's "butter" or "Goldilocks" psi zone. We are arguing about saying the same thing. Look over my posts if you disagree.

  17. #67
    Getaway Cycle Center
    Reputation:
    Join Date
    Nov 2007
    Posts
    180

    conforms to trail surface

    Tubes hold the tire round at the bottom.
    Tubless allows it to conform to the surface giving you wonderful grip.
    As for rolling resistance....dont run super low pressures.
    I run a 29er 2.35 with tube 32psi in rocky north jersey.
    I switched to tubless and run 28-30 psi. Ride wt 200lbs
    Incredible grip performance.......
    When i run below 28 it feels sluggish.
    At 28-30psi i have never flatted, burped or had trouble mounting them for an entire season.
    I have even run none ust tires on none ust rims.....if they snap into the bead then it is a good candidate for tubless.......stans tape & fluid.
    Go tubless for traction.
    I only read a few posts that hit on traction.....but this seems to be the reason that i think you should switch.
    For me it was not weight or supper low pressures.
    After a season on them switching back to tubes does not feel as confident on tricky terrain.

  18. #68
    gran jefe
    Reputation:
    Join Date
    Nov 2011
    Posts
    3,088
    Quote Originally Posted by Nickt30 View Post
    Tubes hold the tire round at the bottom.
    Tubless allows it to conform to the surface giving you wonderful grip.
    Awesome.

  19. #69
    mtbr member
    Reputation: Saul Lumikko's Avatar
    Join Date
    Oct 2012
    Posts
    1,381
    CSC, seems that there was a bit of miscommunication and semantic differences at play. I also think we agree on almost everything with regards to tire pressure.

    Just one thing I call to question, and it's the assertion that higher pressure always means lower rolling resistance. In my opinion it is only true on a perfectly smooth surface: tire deflection is a major contributor in that case. However, if you ride a rock hard tire on asphalt that has seen its better days, the rough surface under the hard tire will result in a higher rolling resistance, while the same tire with a bit less pressure allows the tire to soak up the bumps.

    Here's a good post summarizing what I'm talking about with original sources listed: Road Bike, Cycling Forums - View Single Post - Reduced air pressure for "reduced rolling resistance"??

    In short, I acknowledge that dropping the pressure too low will increase rolling resistance. Quite often tires roll better with a bit higher pressures than lower, but there is also an upper limit, a point where increasing pressure ceases to reduce rolling resistance.

    Edit: A couple links and quotes.

    Bicycle Tires and Tubes
    "In practice, riding surfaces aren't perfectly smooth, and overinflation actually increases rolling resistance, due to vibration."

    Rolling Resistance and Tire Pressure
    "Wider 28-mm tires are as fast at 85 psi as they are at higher pressures."
    "At 130 psi (9 bar), the narrow Clement Criterium rolled slower than it did at a more comfortable 105 psi. The wider Clement Campione del Mundo rolled slightly faster at 85 psi than at 105 psi."
    Last edited by Saul Lumikko; 11-18-2012 at 06:15 PM.

  20. #70
    Cow Clicker
    Reputation: wmac's Avatar
    Join Date
    Sep 2010
    Posts
    2,349
    Good study. A couple thoughts:

    1. This study was conducted using road tires.
    2. This is interesting: "Riding your tires at the “optimum” pressure optimizes both comfort and performance. At lower pressures, you roll slower. At higher pressures your bike is no faster, but much less comfortable. Our tests of the same tires at various pressures determined the
    optimum pressure for each tire for our rider/bike combination." Duh. The question is, how to determine optimum tire pressure for MYB tires. They suggest a method, but not sure if it pertains to MTB tires.
    3. I did not find anything in that study that contradicted anything I've written in this thread.

    I'm beginning to agree with you guys, WTF are we arguing about?

    Why tubeless? Reduce/eliminate flats and have wider range of tire pressure adjustment in order to find "optimum" tire pressure for trail, rider and style.
    No, YOU don't understand. You're making an ass of yourself for all of eternity.

  21. #71
    CSC
    CSC is offline
    mtbr member
    Reputation:
    Join Date
    May 2011
    Posts
    255
    Quote Originally Posted by Saul Lumikko View Post
    CSC, seems that there was a bit of miscommunication and semantic differences at play. I also think we agree on almost everything with regards to tire pressure.

    Just one thing I call to question, and it's the assertion that higher pressure always means lower rolling resistance. In my opinion it is only true on a perfectly smooth surface: tire deflection is a major contributor in that case. However, if you ride a rock hard tire on asphalt that has seen its better days, the rough surface under the hard tire will result in a higher rolling resistance, while the same tire with a bit less pressure allows the tire to soak up the bumps.

    Here's a good post summarizing what I'm talking about with original sources listed: Road Bike, Cycling Forums - View Single Post - Reduced air pressure for "reduced rolling resistance"??

    In short, I acknowledge that dropping the pressure too low will increase rolling resistance. Quite often tires roll better with a bit higher pressures than lower, but there is also an upper limit, a point where increasing pressure ceases to reduce rolling resistance.
    Yes. The "butter zone" takes into account the upper and lower bounds of optimal tire pressure for a given tire.
    A rock hard tire will ride over every single bump, effectively forcing the bike to travel a further distance than if the tire rolls "through" bumps. Think about tens of bumps, each causing millimeter rise and fall in the bike every second...over 20 miles, this will add up to quite a bit of extra distance traveled...hence the advantage of knowing the optimal tire pressure for a given tire, which will reduce this seemingly trivial but incredibly wasteful up-and-down motion of the bike...which also tires out the rider, by the way.

  22. #72
    mtbr member
    Reputation: Saul Lumikko's Avatar
    Join Date
    Oct 2012
    Posts
    1,381
    1. Yes. The info from Schwalbe (who you quoted earlier) is also about road tires: Inflation Pressure | Schwalbe North America
    "The following applies for the road: The higher the inflation pressure the lower the rolling resistance of the tire."

    I think most (if not all) principles can be applied for MTB tires as well: slick is faster, hard is faster - up to a point where you don't gain advantage and start reducing performance.

    A quote from wmac earlier in this thread: "If you are on a surface with a lot of bumps, lower pressure will require less energy to cover the same distance compared to higher pressure."

    This is precisely what I'm also trying to get across. It seems I call this reduced rolling resistance, you call it improved efficiency, for CSC it's something achieved by a "butter zone" pressure. We agree on the practical side, but differ in semantics. I'm happy with that.

    As for a method to find the right MTB tire pressure for yourself, I suggest the following:

    1) If you only ride for your own amusement, try out different pressures and use what feels best.
    2) If you race, time your laps on an actual trail to see which pressure allows you to ride fastest.

  23. #73
    Getaway Cycle Center
    Reputation:
    Join Date
    Nov 2007
    Posts
    180

    just an additional thought

    i truly believe that using a tire pressure with in the range of the recommended pressure listed on the tire is crucial. The side wall is designed to hold strong between those pressures and support the volume of the tire under the rim. Below it and the side wall will collapse and roll out from under the rim causing a wash out. Especially true on a tubeless when there is no tube to help the tire's side wall from folding. The upper limit is more for rim/bead interaction.

    In the Beginning…

    Tubeless officially debuted for mountain bikes in 1999. Mavic, Michelin, and Hutchinson worked together to create a new standard for mountain wheels and tires called Universal System Tubeless, or UST. Under this new standard, the tire’s casing is thicker all the way around – essentially transferring the weight and material of an inner tube on to the tire itself.

    You need the proper inflation to support the volume of air and keep it under the rim.

    this is actually very cool for determining a theroretical tire pressure
    Recommend Tire Pressure « Vittoria

  24. #74
    Cow Clicker
    Reputation: wmac's Avatar
    Join Date
    Sep 2010
    Posts
    2,349
    Saul: Agree, agree, agree. I think the point I was trying to make was that having a higher rolling resistance (lower pressure than butter zone) is a good strategy because many trails have drastically differing terrains and you have to make trade offs based on what is going to net you the greatest efficiency. So, a course that is mostly flat, hard packed with little variation may be best. Change that course to very technical rocky sections that require high traction and grip and you may be better off with lower pressure. Hence, ride the highest pressure possible while maintaining optimal traction in the most difficult sections - just like you also mentioned
    No, YOU don't understand. You're making an ass of yourself for all of eternity.

  25. #75
    mtbr member
    Reputation:
    Join Date
    Sep 2012
    Posts
    134
    I'm sold!! I'm switching to tubeless!!! I never realized this could be so involved, but after reading all these posts I feel I have a better understanding, and can't wait to give it a try. Thanks

Page 3 of 6 FirstFirst 1 2 3 4 5 6 LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •