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Cooper tire pressure - factory reply

Discussion in 'Truck & Equipment Repair' started by Avitare, Dec 5, 2007.

  1. I have read many threads about tire pressure.

    This year, I am trying taller and narrower tires, now that I have found 16in rims
    for this truck. (btw: very happy. great results)

    Lacking reasonable info from the shop, I was puzzled about the Load E and the
    max pressure of 80#.

    I emailed Cooper Tires with the basic info of truck, plow weight and 'rear' weight.
    We dont have a scale near by, but hope to get the operating weight with fuel, me,etc.
    someday soon.
    I also told them my former tires were BFG 31/1.5-15in rated at 50# and the
    new Discover tires are 235/85-16inch. Roughly an inch narrower and 1-inch taller.

    The reply came in only a few days.
    Basically, (without knowing my operating weight specifically) they replied based
    on the prior tires and the operating pressure (then) of 50#.
    They recommended a pressure of 55# to give me similiar load rating for the
    Coopers. And that is what I am running.

    I think it important--particularly with tires-- that operators are aware of facts from the
    factory supplying the tires.
    This is too dangerous to guess and I am greatful for the info from Cooper.
    I am sure that more info regarding actually weight will help them --help us.
    And, I am sure other companys will help, too.
  2. sweetk30

    sweetk30 PlowSite.com Addict
    Messages: 1,588

    all you need is a few min of time and a stick of tire chalk. any vehicle and tire combo. the pressure can be found for best ride and weight holding.

    air tires to what you think is good. then find empty road thats strigh for 1/4-1/2 mile.

    take chalk and put a line across tread nice and solid but not to thick.

    drive truck stright about 1/4-1/2 mile. stop with out turning wheels off stright.

    look at the line you drew on tread.

    you want about 3/4 worn even and last bit on both edges still solid with light wear if any.

    if only a little in center worn then to much air pressure. if all edge wear and no center wear then to low pressure.

    and best fill up tires and let out than have to find a air comp on the road test.

    i did this with my old mud truck . 1 ton chevy with 38" tires. found 25 psi held the best weight and ride. truck was 7k on the scale with me in it.
  3. update

    started this update and lost it to the way-beyond
    try again

    weighed the truck loaded with plow : 6250 # +/-

    As I recall, the front was about 3500#

    I sent the info to the Cooper Customer rep and the reply was that the
    load rating of my tires is 2205# at 50psi.
    That is a total of 8820# or 2500 # more than my total.

    so, I am going to take them back down to 50# (from current 58#)

    That is the lowest inflation recommended to avoid tire damage.
    btw: my tire size is 235/85-16
    this is taller and narrower than stock.

    I appreciate the input from the factory and suggested that (they)
    consider looking at plowsite.com

  4. tkrepairs

    tkrepairs Senior Member
    from maine
    Messages: 186

    i have upsized the tires on my truck to 285/75/16 nokian vatiiva treads, and have found i get best traction at about 48psi for that combo. truck weighs approximately 7400 pounds when plowing. treads in back used to be at 55psi and the front at 45psi and the treadwear was wrong, under pressure in front and over pressure in the back, and 48psi fixed it up pretty evenly. fyi for anyone with that combo...