Results 1 to 11 of 11
  1. #1
    mtbr member
    Reputation:
    Join Date
    Jul 2006
    Posts
    60

    How much tire pressure?

    On my tires it says a minimum of 40psi but it seems people run much lower than whats listed on the tire. How much air should I put in my Trek 4500. I'm 150lbs if it makes a difference. I've been using around 35psi but I just want to know whats ideal. Also should it be higher if I'm riding on pavement?

  2. #2
    govt kontrakt projkt mgr
    Reputation: ArmySlowRdr's Avatar
    Join Date
    Dec 2003
    Posts
    6,176
    I used to use 40 when I was a newb. I accidently put in 40 on a ride last month--the ride is harsh--I was pinging off rocks, nearly going down etc. I've found 30-35 is much better.

    I think I used to use 40 so as to prevent pinches, but I've found better riding technique and not using the lightest tubes allow even a 215 lb person like me get away with running pretty low pressures.

    On d road on my road bike I pump em pretty hard but even here experts say there is a point where harder wont get you any faster.

  3. #3
    ballbuster
    Reputation: pimpbot's Avatar
    Join Date
    Dec 2003
    Posts
    12,639

    I say as low as you can go...

    Quote Originally Posted by Mr.Breeze
    On my tires it says a minimum of 40psi but it seems people run much lower than whats listed on the tire. How much air should I put in my Trek 4500. I'm 150lbs if it makes a difference. I've been using around 35psi but I just want to know whats ideal. Also should it be higher if I'm riding on pavement?
    without:

    pinch flatting
    tire rolling off the rim
    tire feeling mushy or quirmy in the turns

    Apart from that, generally the smaller the tire, the more pressure it needs to keep you up. I typically run 33-35 PSI on 2.25 tires or 38-40 on 2.0s, and I weigh around 200#.

    Lower pressure will get you better traction (until the tire becomes squirmy) and a smoother ride (until you bottom the rim out).

    Higher pressure gets you slightly lower rolling resistance on paved roads, since the tire isn't trying to 'envelope' rocks and stuff.

  4. #4
    mtbr member
    Reputation:
    Join Date
    Jan 2004
    Posts
    6,963
    1/3 of your body weight + 3% x 6 = personal preferance. I run in the 30lb. range depending on the terrain. Try experimenting, lower than 25 psi. may cause flatting.

  5. #5
    mtbr member
    Reputation:
    Join Date
    Aug 2004
    Posts
    163
    Quote Originally Posted by keen
    1/3 of your body weight + 3% x 6 = personal preferance. I run in the 30lb. range depending on the terrain. Try experimenting, lower than 25 psi. may cause flatting.

    Are you sure that formula is right? It tells me 494.4psi

    240 / 3 x 1.03 x 6 = 494.4

    Edit: Ommited something.
    Last edited by Stregone; 09-30-2006 at 06:27 PM.

  6. #6
    NormalNorm
    Reputation: norm's Avatar
    Join Date
    Feb 2005
    Posts
    935
    Quote Originally Posted by Stregone
    Are you sure that formula is right? It tells me 494.4psi

    240 x 1.03 x 6 = 494.4
    LOL....I tried the same thing.

  7. #7
    mtbr member
    Reputation:
    Join Date
    Jan 2004
    Posts
    388
    Quote Originally Posted by Mr.Breeze
    On my tires it says a minimum of 40psi but it seems people run much lower than whats listed on the tire. How much air should I put in my Trek 4500. I'm 150lbs if it makes a difference. I've been using around 35psi but I just want to know whats ideal. Also should it be higher if I'm riding on pavement?

    depends on your weight, terrain you ride, tire size and type (UST or tube), and riding finesse (or not).

    i weigh about 120 lbs, am usually gravity bound on mid-atlantic singletrack, use Michelin 2.0 or Kenda 2.1 tires with tubes, and think i am ok in the finesse department.

    i used to run 35+ lbs front/rear until Shiggy lectured me. now i run 25 front/rear. no pinch flats.

    the ride characteristics of any tire vary greatly with pressure (and between tire brands at teh same pressure). you should experiment and see what you like best.

  8. #8
    www.derbyrims.com
    Reputation: derby's Avatar
    Join Date
    Jan 2004
    Posts
    6,788
    Quote Originally Posted by Phil
    depends on your weight, terrain you ride, tire size and type (UST or tube), and riding finesse (or not).

    i weigh about 120 lbs, am usually gravity bound on mid-atlantic singletrack, use Michelin 2.0 or Kenda 2.1 tires with tubes, and think i am ok in the finesse department.

    i used to run 35+ lbs front/rear until Shiggy lectured me. now i run 25 front/rear. no pinch flats.

    the ride characteristics of any tire vary greatly with pressure (and between tire brands at teh same pressure). you should experiment and see what you like best.
    Try 4 - 5 pound more in the rear than the front for better handling balance and better rolling resistance.

    Pimbot had it right above. It depends on the tire size and stiffness of the sidewall and grip of the tread and terrain.

    Like you say experiment and find what works best for you. But put a little more presure in the rear than the front for best performance.


  9. #9
    mtbr member
    Reputation: xKREDx's Avatar
    Join Date
    Aug 2006
    Posts
    2,263
    Quote Originally Posted by Stregone
    Are you sure that formula is right? It tells me 494.4psi

    240 / 3 x 1.03 x 6 = 494.4

    Edit: Ommited something.
    I did the same thing and it gave me some weired number.
    Quote Originally Posted by shredder111
    Can I paint your rockring, silly bun salad?

  10. #10
    mtbr member
    Reputation:
    Join Date
    Jan 2004
    Posts
    388
    Quote Originally Posted by derby
    Try 4 - 5 pound more in the rear than the front for better handling balance and better rolling resistance.

    Pimbot had it right above. It depends on the tire size and stiffness of the sidewall and grip of the tread and terrain.

    Like you say experiment and find what works best for you. But put a little more presure in the rear than the front for best performance.


    ok, i'll compromise with you, i'll try 25F/28R on my next ride. if i like that better, i'll go a full 4-5 more in the rear like you said. thanks.

  11. #11
    mtbr member
    Reputation: rickm's Avatar
    Join Date
    Dec 2003
    Posts
    141
    i usually run 2 or 3 lbs more air pressure in the back than in the front. 30 in the front, 33 in the rear most of the time on tubed tires without tubes and a body weight of 185. Rocky terrain.
    35,000+Bicycle Parts at BikePartsExpress.com, largest selection of Bike Parts on the web.

Posting Permissions

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