Low tire pressure on street = danger?

Discussion in 'Shop - Miscellaneous' started by rdc, Sep 6, 2001.

  1. rdc

    rdc - users no longer part of the rdc family -

    Joined:
    Dec 31, 1969
    any tire experts out there know if running lower than the normal 35~psi on the street is dangerous? I run my rear tires (33" bfg muds on my toyota) at 22 psi for a smoother ride. Could I be risking a blowout at freeway speeds (sometimes up to 100 mph) running them that low?
  2. sirhk100

    sirhk100 Well-Known Member

    Joined:
    Aug 27, 2001
    Location:
    las vegas, Nv
    Excellent question!!! I'm sure the wear life on them is greatly affected but I never thought about a blow out because of this. I don't corner hard running mine low but I do drive kinda fast, well 85mph max. BTW I'm in a 4 door Exploder on 32" rubbers and run around 25 PSI.
  3. BIG_FAT_LOSER

    BIG_FAT_LOSER Active Member

    Joined:
    Apr 5, 2001
    Location:
    Phelan, Ca
    I have a fairly light truck, Toyota. 31" a/t bfg. And I run 28 front 25 rear and it has been fine for years. Work construction and carry loads. Never a problem. Have been able to get 2 1/2 years plus out of a set with rotating often. Do not know if this psi is proper but has worked for me. Any body else?

    <font color=red>PAT KAPKO</font color=red>
  4. Stan

    Stan Member

    Joined:
    Apr 1, 2001
    Location:
    Central Valley, People\'s Republic of Kali.
    General rule is 80% of the rated max pressure that's listed on the sidewall; that's 28 psi for a tire rated at 35 max. Y'all light truck guys can get away with a little lower pressure, but I wouldn't push it. On my K-5, the lowest I ever run my BFG's are 32 psi, that's just for city driving. Now out in the sand, it's a different story. I've talked to some racers who just run max, but if you're just screwing around, it's okay to air down some. It will also help the tire conform to some obstacle a little better instead of giving maximum resistance resulting in some manual labor.

    "Rehabilitation begins at autopsy."
  5. scott

    scott Active Member

    Joined:
    Apr 2, 2001
    Location:
    Somewhere in California, between L.A./ S.D.
    I run 32 psi on th front, and 25 rear.
  6. drtdevil93

    drtdevil93 Active Member

    Joined:
    Apr 5, 2001
    Location:
    fullerton, ca
    i run mine around 15-20 psi and have never had any problems whatsoever. i get away with it because my yota weighs around 2200 and no bed = no loads. i also drive way too fast most of the time. however there is a noticeable change in handling when you go low, from all the sidewall flex. im sure someone will say thats not nearly enough pressure, but remember, IT WORKS FOR ME.

    erik
  7. fishd00d

    fishd00d What A Joke

    Joined:
    May 9, 2001
    Location:
    San Marcos, CA
    I dont know about you guys but I notice a difference in my gass millage if I go below like 33PSI. I always run mine at 35 just so I get better millage and since I have the tortion bars cranked almost all the way with my stock arms I doubt I would notice any diffenence with ride quality.



    Go Big Or Go Home
  8. Mike_HKmtrsprts

    Mike_HKmtrsprts Member

    Joined:
    May 3, 2001
    Location:
    Huntington Beach
    Fish is right low tire pressure will effect gas milage i always run my tire about a pound or two below what is on the tire for street driving then when i head out to the dirt i air them up all the way, my freind used to work at a tire shop and he said that running tires underinflated on the street causes the side walls to heat up and you chances of a blow out are greater, i have ran my truck from glamis back to brawley on 8 psi running 65mph.....Mike

    You must be Fast cuz I was HAULIN ASS when I passed you...
  9. Greg

    Greg Active Member

    Joined:
    Apr 2, 2001
    Location:
    Riverside, CA
    I run 18-20 in the rear and 23-25 in front. both these pressures were determined by the tread pattern. if I run higher i only use the middle of the tire and lower has too much side wall deflection. I get really good wear this way and the ride is much better than running 30 psi.

    Greg [​IMG]
  10. singlehanded

    singlehanded Active Member

    Joined:
    Jun 3, 2001
    Location:
    Placentia,Orange County
    Greg what kind of tires do you run and what size, and what does the psi rate say on yours. I have 33 bfg mud and they say max load 2225 lbs. at 35 psi. What do you reccommend and if I was running 35" tires would you just use the same percent as you used to get the psi for the 33's? thanks

    local
  11. Jack

    Jack Well-Known Member

    Joined:
    Apr 2, 2001
    Location:
    CA
    just take your contact patch and devide it by the amount of wieght on that tire to get the psi. anything over that should be fine (ie the biger the tire the less presure) know this puts all handeling asside, thats why I say ajust to were it is comfertable and still turns without washing out and check wear to see if you need to go up or down (also may be wrong size rim) but we do weird things with our tires (narrow rims to keep a beed, wide rims more flotation) ( low presure more traction on dirt/rocks/mud/sand, high presure for sidewall protection when running at speed in the dez) So it may not be the same answer for everyone.

    As far as blowouts, I wouldn't worrie about it with an oversized quality tire. Now when it gets all brused for off-road abuse thats a diferent story.
  12. Dylan

    Dylan Member

    Joined:
    May 12, 2001
    Location:
    Orange
    A good way to determine tire pressure empirically is to chalk your tread or drive through dirt, then drive straight for 10 feet or so on pavement. See if the dirt or chalk is wiped of the tread evenly and adjust accordingly. Lower the pressure if its wiped of in the center, raise it if it wipes of more on the edges. If you have a lot of camber due to cranked up ride height or fabtec arms you may not get good contact on the outer part of the tire but when cornering this will change. You can bump the pressure up and down from here to account for gas mileage and handling.
    Low tire pressure off road can offer some forgiveness to the rest of your suspension. It can also account for an additional couple of inches of wheel travel, but watch out, you can break the bead easier . When I go 4 wheeling in the snow I go down to 2 Psi for flotation. The traction difference in this situation is amazing even when going from 3Psi to 2Psi
  13. Greg

    Greg Active Member

    Joined:
    Apr 2, 2001
    Location:
    Riverside, CA
    Actually, i fill them to "recomended" pressure then put some lime on the concrete and drive over it and look at the tire to see which part was touching and adjust my pressure down from there till i get an even contact. I run 35 bfg mud-terrains, with a 65/35 wieght bias and my truck weighs arounds 3500#s.

    Greg [​IMG]

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