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Author Topic:   Tire pressures.
TRAP
Dirt Full Roller

Total posts: 34
posted March 23, 2002 05:41 AM  
I have built an 82 mustang for a 3/8 mile dirt track here in NC. I am new to racing and am totally lost on where to start with tire pressures to help me run around the curves and pull out smoothly. This may be old news to a lot of folks but I really do need the advice. I will have my first practice session on Apr. 6 and would like to start out in the same ballpark as others.
BTW I can only run an 8inch max width tire and must be street tires.

I know the stagger is set with both size tire and pressure but the 8 inch restraint on tire width kind of limits me.
Thanks in advance.

TRAP

[This message has been edited by TRAP (edited March 23, 2002).]

KWTracer
Dirt Freak

Total posts: 233
posted March 23, 2002 07:12 AM  
You'll need to adjust according to track conditions, and vehicle weight. And generally if you run tubes, you can run lower pressures. Anyway, here is what I usually start with:
RF=18
RR=17
LF=15
LR=15


TRAP
Dirt Full Roller

Total posts: 34
posted March 23, 2002 01:29 PM  
Thanks KWTracer,
I needed a good starting point and you helped me out a lot. Im sure I will be asking a whole lot more questions as they arise but already this message board has helped me out in many aspects of car setup.

The track im racing at allows us to use 8" racing recaps, Do you know any suppliers for these. Im told they would be best to use if I can find them.

thanks again

TRAP

[This message has been edited by TRAP (edited March 23, 2002).]

KWTracer
Dirt Freak

Total posts: 233
posted March 23, 2002 02:23 PM  
Try www.retreadsunlimited.com

TRAP
Dirt Full Roller

Total posts: 34
posted March 23, 2002 08:31 PM  
Thanks again, KTWracer thats exactly what im looking for and have a brother in law who says he will pick them up for me to save some shipping charges. He drives a truck through anderson SC weekly.

TRAP

hs
Dirt Full Roller

Total posts: 38
posted March 23, 2002 10:01 PM  
iam in the same spot, this will be my 3rd yr at this. i still have the same problem with tire persure. i hear start low,some people say different.

KWTracer
Dirt Freak

Total posts: 233
posted March 24, 2002 08:50 AM  
Yeah, tire pressures can be kind of a pain. Because when you change an individual tire pressure, your effectively changing the spring rate for that corner also, which changes the setup. I have found that running tire pressure much lower that the starting point that I gave you make ,my car at least, more prone to rolling a tire off, and an extra pound or two just isn't worth having to make a pit stop to me. I generally like to run as low a tire pressure as I can without having to worry about rolling a tire off. But where ever you start as far as pressures, keeps notes of those pressures and how the car worked. Then make small adjustment form there on out while keeping notes as to how those changes affect the car.

hs
Dirt Full Roller

Total posts: 38
posted March 24, 2002 09:01 AM  
thanks kwtracer,
thats one thing iam goin to do this yr is to take notes. how do u know if ur tire is about to roll off, and if u need to +/- air from tires

KWTracer
Dirt Freak

Total posts: 233
posted March 24, 2002 10:55 AM  
Lol, I don't know till it happens. Then I usually go up a pound or so. Pressures aren't usually a problem till you hit a pot hole. Thats what does it to me. Sometimes, if you look at the sidewall of your tire after a race, you can see how far the tire is rolling over. The sidewall will actually have some wear on it and you can get some idea of the deflection. Getting the tire pressure so low that the tire is deflecting enough to show wear on the sidewall is no good either. If your wearing the sidewall you'd need to go up in pressure. This usually only helps after a feature or when the track is dryer. When the track is wet, you have soo much mud and junk on the tire you can't really see much. By the way, there are tools for measureing tire temps, that help you see what your tire pressure, camber and deflection are doing. But after all this isn't nascar. I just try to keep enough air in the right sides that if I hit a hole the tire will stay on the wheel. Keep in mind as the track dries out and gets harder, the tire is going to generate more heat and you'll see increased tire pressure. So, my pressure are usually where I want them mid to end of race. You have to find a happy medium between your start pressures and your final pressures.

[This message has been edited by KWTracer (edited March 24, 2002).]

hs
Dirt Full Roller

Total posts: 38
posted March 24, 2002 04:12 PM  
thanks kwtracer
that should help me some. ive been trying to fine info so i can learn and know what to do at the track to make it handle better. i see other people do it.

hs

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