Recommended tyre pressure HZJ75 on different surfaces

Discussion in '70-Series Tech' started by Paulrotterdam, Aug 10, 2018.

  1. Paulrotterdam

    Paulrotterdam

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    I have been looking in the owner manual and on the bfgoodrich site, but can't really get a clear answer on what pressures to run in different conditions. What are your best practices & recommendations?

    • 1996 HZJ75 troopy with an aluminium flip top roof, full camper interior, 80L water tank, additional 120L fuel tank (mostly empty), one spare tyre. Estimated total weight ~3000kg
    • BFGoodrich KO2 T/A 235x85 R16
    Recommended pressures:

    Front tarmac: ?
    Rear tarmac: ?

    Front gravel: ?
    Rear gravel: ?

    Front sand: ?
    Rear sand: ?

    Front mud: ?
    Rear mud: ?

    Front corrugations: ?
    Rear corrugations: ?
     
  2. TonyP

    TonyP GOLD Star

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  3. FJ73Texas

    FJ73Texas

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    What is the load range of the tire. E?
     
  4. LandCruiserPhil

    LandCruiserPhil Peter Pan Syndrome Supporting Vendor

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    More tire pressure info than you ever wanted to know. pdf attached
    My experience after reading the linked info is most run too much air.

    For offroad I use a square piece of 1.25" material place it under the center of the width of the tire and let air out until both sides of tires touch. Works well with any size tire and any weight vehicle.
     

    Attached Files:

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  5. FJ73Texas

    FJ73Texas

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    Thank you for the awesome reference @LandCruiserPhil , especially since I run Toyo Open Country on the FJ73.

    The JATMA and/or tire and rim association yearbooks are great also but I just don't know if we can share pages out of it online?
     
    Last edited: Aug 10, 2018
  6. coldtaco

    coldtaco

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    take chalk and mark across the tire, then drive slowly forward and/or back until the chalk rubs off. Then check for how the marks are and adjust pressure till you get even chalk wear marks.
     
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  7. Gun Runner 5

    Gun Runner 5 KI4CMQ SILVER Star

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    image.jpeg
    Here is an alternate method which applies to tire pressure when operating off road. (mud, sand etc.). This is often referred to as the "Redneck Method" and is actually quite simple. When your sidewalls look like this you are at the appropriate pressure. :)

    **In the interest of full disclosure, numerous Bud Lights were harmed to make this post possible.
     
    Last edited: Aug 10, 2018
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  8. SNLC

    SNLC OCD Supporting Vendor

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    This^

    If you want to do it right this is how you do it. Contact patch is what matters not pressure.

    Off-road I like to run 8-12psi unless it is high speed, than it is 12-20psi.


    Cheers
     
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  9. Paulrotterdam

    Paulrotterdam

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    After searching on Australian fora, people seem to be running 2.7 bar (40psi) front and 3.7bar (55psi) rear for normal road conditions with a fully laden troopy with 235/85/R16 tyres.

    According to Andrew St Piere Whites Four-Wheel drive book:

    Reduce normal pressure for dirt/corrugations by 10-15%

    Reduce normal pressure for rocks by 15-20%

    Reduce normal pressure for sand by 50-60%
     
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