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Thread: Tire pressure

  1. #1

    Default Tire pressure

    What do you guys set tire pressure at for the track? I'm sure there are a lot of variables, just looking for a starting point. They're at 32psi now.

  2. #2
    FEP Super Member erratic50's Avatar
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    Will depend upon sidewall strength.

    chaulk the tire, roll it ahead, check contact patch. Or do a burnout and check the marks. More fun!

    Its best to play with this just before the rearend is rebuilt when the limited slip clutches are shot. Making both tires burn even eliminates all sorts of monkeybusiness cars like to do off the line.

    26 left rear and 28 right rear is what made my car spin both rear tires when the rearend was open. A few brands of tires will slip on a stock 10 hole at the bead at 26 so mark the rim and tire......

    Cooper Cobra GT's are pretty good for the street. I always liked 235/60/15's although they are just a hair taller than stock.

  3. #3

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    What track (name) and what type of racing?

    Matthew

  4. #4

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    I definitely was not specific enough in my initial post. I ran an open track day on a 1.5 mile road course(Waterford hills mi)on the 2nd. I ran 29psi cold all the way around. It started to oversteer after the first session so I dropped the rear 2psi(33psi hot). ... the drag race info will come in handy though also, I do run drag radials on the street/strip.

  5. #5

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    For road course work you really need a tire temp gauge and a helper or two. The tire temp gauge should be the probe type. You want carcass temperature not tread surface temp which means you will need to push the probe slightly into the tire on the tread surface. Run some laps and get the tires up to temp and then come into the pit or paddock and stop. Have a buddy or two be waiting there to probe the tires on the tread inside, center and outside and record the numbers. Repeat on the tires other side of the car. You will have about 45 seconds to get the numbers (which is why it helps to have two guys) before the tires start to cool. The idea is to adjust the pressure so that the tread temp is fairly even across the tire. Not always possible depending how good the set-up is but that is what you shoot for. Hot in the center, lower the pressure. Hot on the outsides, more pressure. Hot on the just the inside or outside, maybe the camber setting but you can still usually minimize the uneven temps. The learning curve isn't too steep. You will find that from track to track you will rarely have the same pressure on each corner of the car. All tracks are different as well as drivers. You will also find that once you get consistency with this process you will significantly reduce your lap times.

    Matthew
    Last edited by 86FOX4EYE; 07-05-2017 at 03:09 PM.

  6. #6

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    Good info. I've never heard of a tire temp gauge but I'll be getting one now. Thanks

  7. #7

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    Sorry, they are actually called a pyrometer. You don't need one with the bells and whistles. They are convenient but expensive so you make your own choice. I got along with a simple one like the one in the link for years. Learning to use it properly is much more important than spending money on convenience. What you don't want is an infrared pyrometer. They will take only surface temperature which is not very useful.

    https://www.summitracing.com/parts/lng-50635?seid=srese1&cm_mmc=pla-google-_-shopping-_-srese1-_-longacre-racing-products&gclid=CNrg-qTW9NQCFZ2PswodvJcC9w


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