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What tirepressure do you run? Street vs Trail

Discussion in 'The Garage' started by ankarback, Feb 7, 2006.

  1. ankarback

    ankarback 1/2 ton status

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    I know you can't run the factory spec. on bigger tires but what is the correct tirepressure for the street vs on the trail. What pressure do you run and on wich tires? I know there's not a correct tire pressure for the trail but what works best for your truck?
     
  2. goldwing2000

    goldwing2000 Guest

    I run 25-28 all the time. I only "air down" for sand.
    There are no rocks in Michigan. :D
     
  3. thezentree

    thezentree 3/4 ton status

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    33-35 for street and 12-15 for trail. When I had time to go wheelin....

    I never really did a whole lot of rocks, but the one time I did (yea, in a stock yukon) 12psi seemed to work pretty well considering I was running BFG A/Ts.
     
  4. trailblazr81

    trailblazr81 1/2 ton status

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    Ya, I stay 32-36 on the street and 12-16 on the trail. Would like to go lower but I dont have beadlocks... BFG M/T 35x12.5x15
     
    Last edited: Feb 7, 2006
  5. mudhog

    mudhog THEGAME Staff Member Super Moderator

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    with my 40in iroks i run 23psi street 8-12psi trail and 4-8psi sand and snow
     
  6. MTMike

    MTMike 1/2 ton status

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    I don't see the street so I run 10-15 in mine with the 16.5" wheels

    When I get the run-flat hummer rims and onboard air installed, I will run ~5 in the snow, 8-10 on the trail and 20 when on the trailer or for any highway time.
     
  7. Geargrinder

    Geargrinder 1/2 ton status

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    I run 28psi on the street and 10-15psi on the trail. I came up with 28 for the street by useing my lazer temp gun across the tire till I got even temps all the way across(about 97deg.) That's on a 7800# 'Burb w/35's (Hi-tech re-treds)
     
  8. trailblazr81

    trailblazr81 1/2 ton status

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    :bow: That is waaay to technical for me. Especially on my beater truck. Tho it might be a good idea when I start taking my moded Mustang to the track.:D
     
  9. muddybuddy

    muddybuddy 3/4 ton status

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    what would be the optimal psi for 42s on 15" rim on the street? around 25psi? i bought them used and the centers are worn more than the sides so i want to maximumize the remainding life of them. thank :D
     
  10. 4xcrazy

    4xcrazy 3/4 ton status

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    35-40 on the street

    22-28 on the trails


    edit* that's what i run
     
  11. JpEater

    JpEater 1/2 ton status

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    20 lbs street and 8-10 trail w/no beadlocks. 37'' boggers and they wear evenly @20
     
  12. roadnotca

    roadnotca 3/4 ton status

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    '85 Burb. I have BFG "E" rated tires, been experimenting with Hi-way pressures; now at 60 psi. Trail with rock, I just tried 15 psi last weekend, seemed to be fine. I have done 18 psi and drove some asphault up to 30 mph with curves, they moved about 5 inches at the rim. I broke all of them off the bead and remounted them; at 70-80 mph it makes a difference, just like I knock off the big mud so they aren't out of balance for the trip home.:D
     
  13. blazinzuk

    blazinzuk Buzzbox voodoo Premium Member GMOTM Winner

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    Okay I hope I remember this right with your tires cold check your air pressure get in your truck drive for about one hour check your air pressure again if the pressure has gone up 4 lbs you have the correct pressure for your truck, that is all I remember, got this off Pirellis website a while back. Feel free to correct me if I am wrong :D
     
  14. ankarback

    ankarback 1/2 ton status

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    Seems like most of you run around 30psi for around 35" tires, that's what I've figured out works best for mine too. I run 305/70-16 om my sub.

    I've read somewhere (maybe in fourwheeler) that it's the total amount of air in a tire that supports the truck so a bigger tire should therefore require lower airpressure than a smaller one.

    Do someone know a way to calculate this or is it trail and error to get it right?
     
  15. roadnotca

    roadnotca 3/4 ton status

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    I think GearGrinder has perfected it with the laser temp gun, and that would be for any tire, any vehicle. I want one now.
     
  16. Jishory

    Jishory 1/2 ton status

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    I use 20-25 all the time because i need onboard air :D unless im going somewhere far then i might go 30 depending how loaded down I am.
     
  17. DieselDan

    DieselDan 1/2 ton status

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    KEY - tire size will have a direct significance regarding air pressure (as much or more than vehicle weight IMHO).

    38x15.5Rx15" running 25 front 22 rear for street (still playing with pressures)
    I'm still pushing my luck off-road, "let's see how 4 PSI works":haha:

    FYI: Army HMMWV on 37x12.5Rx16.6 runs 22 PSI (at normal running weight)
     
  18. ankarback

    ankarback 1/2 ton status

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    Yes, that's a way to do it but a laser temp gun sounds very expensive. I was thinking there was some kind of formula you could use to calculate the amount of air in the tire (pressure and volume) that is neccesary to carry a specific weight. Humh....That sounded very complicated.... :D.
     
  19. 6.2Blazer

    6.2Blazer 1/2 ton status

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    Definitely a good point.......tire size GREATLY affects how much air pressure is needed. My towrig had 245/75R16 tires and my trailrig has 38x13-16's. At 20 psi the 245's looked almost flat, while the 38's were hard as a rock with no flex.
     
  20. Blue85

    Blue85 Troll Premium Member

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    That's a lot of air. I would use 32psi for 29" tires. Notice that Geargrinder found 28psi to be correct with 35's on a Burb. A K-5 is lighter and would need even less, although it's about the same thing I use.

    This has been discussed before, but a good ball-park figure is to take the weight on the tire (measured or estimated), multiply by the maximum rated pressure (sidewall) and divide by the maximum load rating of the tire (also on the sidewall).

    The bigger the tire, the less air you need. PSI= lbs per square inch and you are making the contact patch larger and keeping the weight the same.
     

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