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Tire Pressure

Discussion in 'Early CJ5 and CJ6 Tech' started by 1967 CJ5A, Oct 2, 2014.

  1. Oct 2, 2014
    1967 CJ5A

    1967 CJ5A Mike 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Raleigh, NC
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    A few weeks ago I bought a new set of Super Traxion 7.00-15 bias ply tires. I'll be taking the Jeep off road pretty soon, and I'm not sure what pressure I can safely air down to with these tires (I have stock rims). Does anyone have any suggestions/experience?

    Thanks!
     
    1967 CJ5A, Oct 2, 2014
    #1
  2. Oct 2, 2014
    Glenn

    Glenn Kinda grumpy old man Staff Member

    Apopka, Fl
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    Personally I doubt you would gain anything by airing down that size tire, especially since the sidewall is probably pretty stiff.
     
    Glenn, Oct 2, 2014
    #2
  3. Oct 2, 2014
    Jw60

    Jw60 Cool school 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Sedalia MO.
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    1960 owners manual says 14psi for agricultural use of the stock 7 x 15
    20psi for the 6 x 16
     
    Jw60, Oct 2, 2014
    #3
  4. Oct 2, 2014
    PeteL

    PeteL If it wasn't for physics, and law enforcement... 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Hills of NH
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    I wouldn't air-down for ordinary use, but I can say for sure dropping the pressure on bias tires has gotten me out of bad situations where I needed more traction.
     
    PeteL, Oct 2, 2014
    #4
  5. Oct 3, 2014
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Medford Mass USA
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    Yep, airing down helps, regardless of the tire size.
     
    timgr, Oct 3, 2014
    #5
  6. Oct 3, 2014
    Glenn

    Glenn Kinda grumpy old man Staff Member

    Apopka, Fl
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    Interesting, I wouldn't have thought it would help much with a smaller tire. I know it definitely does help with larger tires. I never tried it myself with smaller tires.
     
    Glenn, Oct 3, 2014
    #6
  7. Oct 3, 2014
    Howard Eisenhauer

    Howard Eisenhauer Administrator Staff Member

    Tantallon, Nova...
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    I'm pretty sure people have been airing down since the advent of the balloon tire in the 30's. I know somewheres in my old stack of Popular Mechanics mags I've read stories from the early 50's about Model A "Beach Buggies" running aired down tires for traction in sand &, as was prevalent at the time, getting passenger cars un-stuck on muddy roads. I suspect that pre-dates the (ducking) "Lets equate Tire Size with Penis Size" period :twisted:

    H. :)
     
    Last edited: Oct 4, 2014
    Howard Eisenhauer, Oct 3, 2014
    #7
  8. Oct 3, 2014
    jzeber

    jzeber Well-Known Member 2022 Sponsor

    Morgan Hill, Ca
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    Different tire size but I usually run my tires at 8 to 10 psi off road.
     
    jzeber, Oct 3, 2014
    #8
  9. Oct 4, 2014
    oddfirejeeper

    oddfirejeeper Active Member

    Hamilton, MI
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    if you don't air down tires in sand the tires will dig to china no matter the size. it also makes the tire conform to whatever it's making contact with (better traction) rocks. dirt
     
    oddfirejeeper, Oct 4, 2014
    #9
  10. Oct 5, 2014
    Billywam

    Billywam Billywam

    Lyons, Colorado
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    This picture was circulated recently on Crawlarado's Facebook page. Probably not as relevant to your question for your tire size, but still impressive.

    [​IMG]
     
    Billywam, Oct 5, 2014
    #10
  11. Oct 5, 2014
    Mike C

    Mike C Member

    Austin, TX
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    Low pressure makes for a much smoother ride offroad as well. I ran the NDT's on the MB at 12 psi just for that.
     
    Mike C, Oct 5, 2014
    #11
  12. Oct 6, 2014
    Brian P

    Brian P Member

    Clarkdale Arizona
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    I run 7.00 15s on one of mine, I agree that airing down can improve traction in certain soil conditions but for those of us that don't have extremes of soil types one middle of the road air pressure works well. I have found good all round performance in traction, ride, steering and tire wear on pavement running 16 psi in the rear and 20 psi in the front, this is for a moderately loaded rig with ice chest and day ride necessities for two. This should be a good trial pressure for you. Heavier loads of course would require a little more air.


    A tire only needs enough pressure to maintain its design profile with a given load for good performance on hard surfaces.
     
    Brian P, Oct 6, 2014
    #12
  13. Oct 6, 2014
    Alan28

    Alan28 Well-Known Member 2022 Sponsor

    Châtillon en...
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    I just aired down to have more comfort, my tires were too hard for my body, and the new shock-absorbers don't change anything.
    But there is a minimum for safe driving!
     
    Alan28, Oct 6, 2014
    #13
  14. Oct 7, 2014
    Corveeper

    Corveeper Member

    Chanute, Kansas
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    Cool. Copied and saved for future reference, hope you don't mind.
    On a side note, I would be careful about airing down below 10 psi on any non-bead locked rim. Single digit air pressures is flirting with a slipped bead on a standard type rim.
     
    Corveeper, Oct 7, 2014
    #14
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