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.
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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.
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  1. #1
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    Air pressure for tube in tubeless and standard tires on tubeless wheels?

    Hello,

    I just bought a bike with a pair of Mavic Crossmax UST wheels and tubeless tires. I am new at cycling. The front, I believe, already has a tube in it (the Presta valve can be wiggled around and does not have a locking nut on the outside). Having read a few articles about tubeless -> tube, I have some questions.

    1) I presume it is okay to run tubes in these wheels indefinitely?

    2) Is it possible to run standard steel/kevlar/clincher bead tires in these wheels? (with tubes, of, course).

    3) The tubeless tires indicate a maximum 50 PSI air pressure. When I have a tube inside, should I observe the same maximum PSI?

    4) Once I go with standard tires, presuming it is okay, can I run the higher pressure supported by the new tires?

    I plan to do only light XC and path/trail riding for now, so I want a simple and higher-pressure set up.

    Bonus questions:

    Do "Kevlar inside" or Kevlar-belted tires do a good job as being puncture resistant? Or, do thicker rubber work better? What is the best puncture-resistant set up?

    Thanks very much.

  2. #2
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    1) Yes

    2) Yes (it's possible to do it without tubes too)

    3) You could (each tire brand has a max psi stamped on it)

    4) Yes, but I think the max of the rim is 60....check

    I strongly recommend running a lower pressure. While riding on the road may be a bit faster, there have been numerous tests that show a lower pressure is faster on trails.

    I have the a set of crossmax ST and run regular tires on them without tubes (plus some sealant) and I run them at around 30-32 psi (I am ~210lbs). Save the high pressures for the road bike.


    EDIT** Check out these threads

    Tire pressure for all around XC riding?
    stans rolling resistance 101
    lower pressure= less rolling resistance!
    Quote Originally Posted by snovvman

    Bonus questions:

    Do "Kevlar inside" or Kevlar-belted tires do a good job as being puncture resistant? Or, do thicker rubber work better? What is the best puncture-resistant set up?

    Thanks very much.
    IIRC kevlar belted only refers to the bead that clinches the rim, and kevlar is lighter than a steel bead and can be folded. Thicker rubber works for puncture resistance, running tubeless with sealant works very well too.
    Last edited by civil; 01-25-2010 at 09:07 AM.

  3. #3
    cougarbait
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    you should take advantage of your setup and go tubeless indefinitely
    09AS-Rsl/09Six

  4. #4
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    I strongly recommend running a lower pressure. While riding on the road may be a bit faster, there have been numerous tests that show a lower pressure is faster on trails.
    I've only seen one study, and it was an absolute twisting of data to support a false statement. Don't get me wrong, I support the idea that lower air pressures does have advantages, but speed is not(directly) one of them.
    Care to share some of these "numerous tests"?

  5. #5
    Underskilled
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    You have tubeless rims, it would be a huge waste to run a tube.

    Lower pressure has higher rolling resistance, much less of an effect when running tubeless.
    However the tractionincrease means you can corner faster, brake later ride at a higher speed.

    So rolling resistance is faster at 60PSI, but I will get around my local trail centre faster at 30 PSI.


    Get your tyres set up tubeless and run at 30-40 psi, trust me, worth it.

  6. #6
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    Quote Originally Posted by JPark
    I've only seen one study, and it was an absolute twisting of data to support a false statement. Don't get me wrong, I support the idea that lower air pressures does have advantages, but speed is not(directly) one of them.
    Care to share some of these "numerous tests"?
    Maybe "a couple" would have been a better choice than "numerous". Over the last 3 years I've seen two on this site from a german magazine, 2 from some separate manufacturer's and some independent ones (3) on the net. I can't pick them out as they are buried somewhere but with some searching you should be able to dig them up.

    They are just tests, subject to error, mis-interpretation and assumptions, however they all point to lower pressure being faster on the trail, for various reasons. Some of which I agree with and thus run my tires low.

  7. #7
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    Thanks for your replies.

    Quote Originally Posted by civil

    1) Yes

    2) Yes (it's possible to do it without tubes too)

    3) You could (each tire brand has a max psi stamped on it)

    4) Yes, but I think the max of the rim is 60....check

    I strongly recommend running a lower pressure. While riding on the road may be a bit faster, there have been numerous tests that show a lower pressure is faster on trails.

    I have the a set of crossmax ST and run regular tires on them without tubes (plus some sealant) and I run them at around 30-32 psi (I am ~210lbs). Save the high pressures for the road bike.

    EDIT** Check out these threads

    Tire pressure for all around XC riding?
    stans rolling resistance 101
    lower pressure= less rolling resistance!

    IIRC kevlar belted only refers to the bead that clinches the rim, and kevlar is lighter than a steel bead and can be folded. Thicker rubber works for puncture resistance, running tubeless with sealant works very well too.
    Follow up questions:

    From #2, if I were to use a standard tire without tubes on the UST wheels, I presume I have to use glue?

    #4, I searched for maximum pressure specifications for the Crossmax SL UST, but have not been able to find one. If I were to use an inner tube, does the max pressure rating for the wheel still matter? I thought it was only the pressure rating on the tire?

    Quote Originally Posted by Lambdamaster
    you should take advantage of your setup and go tubeless indefinitely
    I do want to. At the same time, there is something attractive about the easy support/change for a tube-based setup.


    Another question: How does the NoTube sealant work? Like Slime?

    Thanks again.

  8. #8
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    Quote Originally Posted by civil
    IIRC kevlar belted only refers to the bead that clinches the rim, and kevlar is lighter than a steel bead and can be folded. Thicker rubber works for puncture resistance, running tubeless with sealant works very well too.
    These are two Kevlar belt tires I'm talking about. I spoke with the manufacture and it is not in the bead. These are Kevlar belts embedded across the tread of the tire to help prevent puncture.

    http://www.maxxis.com/Bicycle/Hybrid/Overdrive.aspx

    http://www.csttires.com/Bicycle/City...r/Selecta.aspx

    I looked for reviews but didn't find much. I just wonder how effective it is.

  9. #9
    Probably drunk right now
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    I've only seen one....

    Quote Originally Posted by civil
    Maybe "a couple" would have been a better choice than "numerous". Over the last 3 years I've seen two on this site from a german magazine, 2 from some separate manufacturer's and some independent ones (3) on the net. I can't pick them out as they are buried somewhere but with some searching you should be able to dig them up.

    They are just tests, subject to error, mis-interpretation and assumptions, however they all point to lower pressure being faster on the trail, for various reasons. Some of which I agree with and thus run my tires low.

    Please cite your sources. The only "study" I've seen was the magazine article in the German magazine. If you dig a little deeper, you would have learned that the study was funded by Michelin and Maxxis shortly after both companies launched the UST standard.

    I'd love to see one credible study and source, much less a couple.

  10. #10
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    Quote Originally Posted by CaveGiant
    You have tubeless rims, it would be a huge waste to run a tube.

    Lower pressure has higher rolling resistance, much less of an effect when running tubeless.
    However the tractionincrease means you can corner faster, brake later ride at a higher speed.

    So rolling resistance is faster at 60PSI, but I will get around my local trail centre faster at 30 PSI.


    Get your tyres set up tubeless and run at 30-40 psi, trust me, worth it.

    +1

    except 40 psi is a bit on the high side IMHO......i weigh 180# and run my tubeless for rigid at 28 lbs(r) and 26lbs(f).....

    also...go here...great site:
    http://www.sheldonbrown.com/tires.html
    Visit these 2 places to help advance trail access:
    http://www.sharingthepct.org/
    http://www.facebook.com/SharingThePct

  11. #11
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    Quote Originally Posted by Ken in KC
    Please cite your sources.
    Your answer is in what you quoted.

    Quote Originally Posted by Ken in KC
    you would have learned that the study was funded by Michelin and Maxxis
    That was obvious from the article, but while it may be biased (as with almost all scientific research) it was better that the data you presented for me (nothing).

    Quote Originally Posted by Ken in KC
    I'd love to see one credible study and source, much less a couple.
    I'd love to see more too, but it isn't exactly a high priority area of study, so you have to take what you can get and interpret those results.

  12. #12
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    Ah.....

    Quote Originally Posted by civil
    Your answer is in what you quoted.



    That was obvious from the article, but while it may be biased (as with almost all scientific research) it was better that the data you presented for me (nothing).



    I'd love to see more too, but it isn't exactly a high priority area of study, so you have to take what you can get and interpret those results.

    So "numerous" went to "a couple" and now it's one German mountain bike magazine writing an article about a "study" conducted conducted by the two companies that introduced the UST system? Got it.

    Since you brought up scientific research, then I'm sure you know that the burden of proof is with the person presenting the theory and their approach is to set out to disprove their theory, right?

    You made some pretty sweeping generalizations about tubeless benefits based on "numerous" and then "a couple" "studies" from the german magazine, manufacturers and some independent ones. I'm just asking to see the studies that I haven't seen.

  13. #13
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    Quote Originally Posted by civil
    ...While riding on the road may be a bit faster, there have been numerous tests that show a lower pressure is faster on trails.

    ....
    CaveGiant already responded to this accurately.....don't know what the hubBub is about....

    yes...lower pressure will be faster on trails.....simple answer is more/better traction....
    Visit these 2 places to help advance trail access:
    http://www.sharingthepct.org/
    http://www.facebook.com/SharingThePct

  14. #14
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    Quote Originally Posted by Ken in KC
    So "numerous" went to "a couple"
    Fair enough, I re-stated that before you joined this thread though.

    Quote Originally Posted by Ken in KC
    and now it's one German mountain bike magazine writing an article about a "study" conducted conducted by the two companies that introduced the UST system? Got it.
    Nope, I never said it was one, you did.

    Quote Originally Posted by Ken in KC
    Since you brought up scientific research, then I'm sure you know that the burden of proof is with the person presenting the theory and their approach is to set out to disprove their theory, right?
    Sure, but I'm not presenting the theory. I merely stating what I have seen. It's up to you if you want to believe it, or pursue it any further.


    Quote Originally Posted by Ken in KC
    You made some pretty sweeping generalizations about tubeless benefits
    No sweeping generalization, just the observation that lower pressure is better/faster.


    Quote Originally Posted by Ken in KC
    I'm just asking to see the studies that I haven't seen.
    And I've told you, your answer is in your first quoted post. Unfortunately I don't keep 3 year records of my browsing history.

    This isn't a scientific community, people can present stuff and the reader has to interpret it as he/she see's fit. If you don't agree that's fine. If you want to call it full of @@$$ that's fine too.

  15. #15
    IdontShootPeopleAnyMore
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    snovvman you are dam lucky (or loaded) if you are just getting into mtn biking and you are rocking crossmax wheels thats like buying a lotus to learn how to drive... what kind of bike are they on if you dont mind me askin?
    What mountain bike forum do pirates use? .....



    MTB-arrrrrrrrrrrrrrr

  16. #16
    IdontShootPeopleAnyMore
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    oh and to all you debating about what is faster low psi or hi psi, if its rocky and rough and you run high psi you will proabaly shake your self to death and have a dam violent ride glancing off every root and rock and not have good grip on the trail and proabably fall off a clif and impale your rib cage with your handlebars. so yes in MTN biking low psi winns races so therefore is scientifically faster... trust me Im a scientist
    What mountain bike forum do pirates use? .....



    MTB-arrrrrrrrrrrrrrr

  17. #17
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    I'd love to see one credible study and source, much less a couple.
    My point exactly, so.....anyone?

  18. #18
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    Quote Originally Posted by JPark
    My point exactly, so.....anyone?
    Well sorry, I can't provide any links.

    Feel free to run higher pressures if you like.

    But did I mention that I have seen numerous studies that have shown.........

  19. #19
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    Quote Originally Posted by JPark
    My point exactly, so.....anyone?
    Sheldon Brown:
    Overinflation:
    * An overinflated tire will have slightly less rolling resistance.
    * An overinflated tire is more prone to damage from sharp rocks and similar road hazards.
    * An overinflated tire will give a harsh ride on anything but the smoothest pavement.
    * An overinflated tire can bounce on surface roughnesses. This can cause dangerous interruptions in traction, particularly if it happens during cornering.

    traction is king.....higher pressure solely to decrease rolling resistance will get you clobbered...
    Visit these 2 places to help advance trail access:
    http://www.sharingthepct.org/
    http://www.facebook.com/SharingThePct

  20. #20
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    CaveGiant already responded to this accurately.....don't know what the hubBub is about....

    yes...lower pressure will be faster on trails.....simple answer is more/better traction....
    Missed his post the first time.
    Again, I agree that lower pressure has advantages, but speed is not a consistant advantage to be gained by simply lowering your air pressure.
    Unless you consistantly ride to your technical riding limits over the entire ride, the advantage gained will never overcome the higher rolling resistance, which is a constant over the entire ride.
    Though obviously there are exceptions, most riders will be faster by running as high a pressure as terrain and ability will allow.

  21. #21
    fresh fish in stock...... SuperModerator
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    Quote Originally Posted by JPark
    Missed his post the first time.
    Again, I agree that lower pressure has advantages, but speed is not a consistant advantage to be gained by simply lowering your air pressure.
    Unless you consistantly ride to your technical riding limits over the entire ride, the advantage gained will never overcome the higher rolling resistance, which is a constant over the entire ride.
    Though obviously there are exceptions, most riders will be faster by running as high a pressure as terrain and ability will allow.
    true...true.....too low is muy mal.....

    too high is also no bueno

    just right is:
    * A correctly inflated tire will have negligible rolling resistance.
    * A correctly inflated tire will not get pinch flats in normal use.
    * A correctly inflated tire will absorb minor surface irregularities, improving rider comfort.
    * A correctly inflated tire will absorb surface irregularities without bouncing and losing traction.

    (again...from Sheldon Browns site...damn good site)

    PS....tire pressure is also dependent on the tire/tread itself.....this is where Shiggy would have some solid answers/experience......
    Visit these 2 places to help advance trail access:
    http://www.sharingthepct.org/
    http://www.facebook.com/SharingThePct

  22. #22
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    Quote Originally Posted by DriveByBikeShooting
    snovvman you are dam lucky (or loaded) if you are just getting into mtn biking and you are rocking crossmax wheels thats like buying a lotus to learn how to drive... what kind of bike are they on if you dont mind me askin?
    Thanks. Giant NRS Air is what I bought. I realized that I wanted a mountain bike that I can ride on paths, trails, and take jumps off stairs, steps, curbs, etc. I wanted something light and does not bob when pedling. We'll see--I haven't ridden it yet...

    The bike is cool, XT parts and XTR rear derailer, hydraulic disc brakes, carbon handle bar and seat post, carbon frame and rocker, all in a neat 24 lb package.

  23. #23
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    Sorry to have started a fire about inflation pressure vs. rolling resistance.

    Still my questions: If I were to use a tube, the maxium pressure is determined by the tire--correct? Does the wheel itself have a pressure rating, when the tube is used?

    Please see post #8,

    http://www.maxxis.com/Bicycle/Hybrid/Overdrive.aspx

    http://www.csttires.com/Bicycle/City...r/Selecta.aspx

    These tires seem to have Kevlar belts in the tread that resists puncture. I would like to get feedback on how well they work.

    Thanks.

  24. #24
    Can't feel my legs
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    Quote Originally Posted by snovvman
    Sorry to have started a fire about inflation pressure vs. rolling resistance.

    Still my questions: If I were to use a tube, the maxium pressure is determined by the tire--correct? Does the wheel itself have a pressure rating, when the tube is used?

    Please see post #8,

    http://www.maxxis.com/Bicycle/Hybrid/Overdrive.aspx

    http://www.csttires.com/Bicycle/City...r/Selecta.aspx

    These tires seem to have Kevlar belts in the tread that resists puncture. I would like to get feedback on how well they work.

    Thanks.
    You didn't start a war, just a healthy debate on the merits of [SIZE="3"]proper[/SIZE] inflation.
    Yes, max inflation is determined by tire manufacturer. I doubt you will ever exceed the limits of any rim by inflating to the max recomended pressure of any tire.

  25. #25
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    You're missing the point....

    Quote Originally Posted by civil
    Well sorry, I can't provide any links.

    Feel free to run higher pressures if you like.

    But did I mention that I have seen numerous studies that have shown.........

    I've seen numerous studies indicating that I can outride Ned Overend, Steve Pete and Allison Dunlop.

    Do you assume that my statement is correct because I said that I've seen studies?

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