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FZJ80 with Cooper STT Pro 305/70r16 - what tire pressure?

Discussion in 'Tire and Wheel Tech' started by cbpeck, Feb 13, 2018.

  1. cbpeck

    cbpeck

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    About a thousand miles ago I put a set of Cooper STT Pro tires on my '97 fzj80. They are size 305/70r16 and were installed on freshly powder coated factory wheels. Costco aired them up to about 50 psi, and I dropped them to around 40 first, then 36, then 32. At 32 psi only about 80% of the tread was making contact with the ground (wet tires on dry pavement). I aired them down to 30 psi and now seem to be getting contact across at least 95% of the tread on pavement. They've been at 30 psi for about the last 600 miles. I've never ran tires this low on the street, but I've also never owned a set of load range E tires. I typically air down off road, so I'm not concerned about that. I just want to make sure that the on-road tire pressure is appropriate so the tires wear evenly. FYI, the Cruiser is stock, and the truck is generally empty when I use it as my daily.

    I'd appreciate any advice or suggestions you guys have. Thanks!
     
  2. gregnash

    gregnash Anal Retentive Analyst SILVER Star

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    Aren't Load E rated tires meant mainly for towing heavy load? This may be why you are having to see such low pressures to allow for full contact patch?! Might be worthwhile to shoot Cooper an email and ask their advice.
     
  3. cbpeck

    cbpeck

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    E rated tires do have a heavier load capability, but they're also desireable because they are generally more puncture resistant than lighter tires.
    It's helpful to hear from people who have experience with these trucks, so I may post in the 80 section as well. And contacting Cooper isn't a bad idea. I may try that too.