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Why go tubeless?

19K views 126 replies 43 participants last post by  desertred 
#1 ·
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.
 
#37 ·
A roadie (135lb lightweight) on rock hard tires at 120psi or rock hard tires at 100psi? Neither are going to deform (flatten) the contact patch with pressures that high with so little volume. Air up that road tire to 50psi and there will be a difference in rolling resistance. If there wasn't, they would only use 50psi. Mountain bike tires have much more volume and are used at much lower pressure. A "flatter" tire is going to roll slower. Mountain bike, car, trailer, dolly, hula hoop, and even a roadie tire. I can feel the difference with my legs between a 45psi tire and a 30psi tire.
 
#41 ·
They told me bathing in boiling water would be fatal, so I dropped the temperature below zero and it froze. I still didn't get the bath. :(

That's what I think when I read stuff about lower pressures increasing rolling resistance. Well of course the rolling resistance will be higher, if you're riding flattened 2.35 mm mud tires on smooth pavement. What happens on the trail is vastly different.
 
#42 ·
A flat tire on or off road does increase rolling resistance. I guarantee it.

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.

And what does any of this have to do with tubed vs tubeless, anyway?
 
#45 ·
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. The reason this is relevant is because you can run lower pressures, when necessary, with a tubeless setup compared to a tubed set up. Running lower pressures is not more efficient on every trail.
 
#64 ·
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.
 
#47 ·
You could in theory run them flat (no air...) on a smooth surface...assuming you did not cut the wall of the tube with your rim or something on the ground.

In practice, you would have to have enough air to press and hold the tire bead to the rim...in the neighborhood of 15-20 psi, to be safe. I have ridden on less than 20 psi...not great, but possible. Tubeless allows you to glue the bead to the rim, so you might get lower psi on the tubeless set-up, but things would start getting sketchy.

EDIT: I mean, no one would run 15 psi tubeless, right?

The whole issue is how low can you go and not have the tire pop off the rim or compress and get lacerated by the rim? Tubeless gives you a bit more flexibility.
 
#50 ·
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.
 
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#58 ·
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!
 
#63 ·
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.

 
#67 ·
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.
 
#69 · (Edited)
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."
 
#71 ·
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.
 
#70 ·
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.
 
#72 ·
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.
 
#73 ·
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
 
#74 ·
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 :)
 
#78 ·
Just one more thing, in the spirit of Columbo. Couldn't resist...

I think we went a bit off-topic with the tubeless thing when one benefit of tubeless was said to be the ability to run lower pressures. From there it went to pressures without regards to tube vs. tubeless.

We overlooked the fact that the comparison wasn't between the same setup with a higher and lower pressure, but rather "with a tube, higher pressure" and "tubeless, lower pressure".

I would argue that removing the tube has a positive effect on rolling resistance, which may be negated by lower pressure, so one hypothetic outcome would be "less pressure, same rolling resistance". I.E. when you go tubeless, you can run lower pressures for the traction and smooth ride without increasing rolling resistance compared to your old setup with tubes.
 
#79 ·
Great point Saul! For those lurking noobs - the reason this is the case is because it takes energy to deform a pressurized tire and tube. It takes energy to pinch a tire and tube, right? Same thing is constantly happening when you are riding. As you ride, the tire and tube has to constantly change from round to flat to round as it passes over the contact patch. When you eliminate the tube, you energy the loss that happens when the tube goes through that cycle.

So, it's true when converting the same tire with and without tubes. It might not be the case if you go from a standard tire with tubes to a UST tire because of the stiffness of the sidewall, etc. This is why lighter tires often have lower rolling resistance- because it takes less energy for the casing to go from round to flat to negative arc (for roots and rocks) and back to round.

This principle also explains why it is more difficult to push that dolly with low pressure tires compared to higher pressure. But, put a stick in front of that Dolly's tires and the force that is required to push the dolly over the stick is lower with lower pressure tires compared to higher pressure tires. The "butter zone" is to minimize the force required to move over smooth and irregular surfaces.
 
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