# Chalking your tires??



## SR20 Who Knew? (Jul 29, 2003)

What does "chalking" your tires do in autocross mean? I see it in alot autocross sites but don't know what it is or what it does. Someone enlighten me on the topic and :givebeer: ....


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## morepower2 (Apr 19, 2002)

SR20 Who Knew? said:


> What does "chalking" your tires do in autocross mean? I see it in alot autocross sites but don't know what it is or what it does. Someone enlighten me on the topic and :givebeer: ....


putting a mark on your sidewall so when you adjust the air pressure, you add air until the chalk gets rubbed off just to the sholder of the tread and not up the sidewall.

Mike


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## SR20 Who Knew? (Jul 29, 2003)

Where on the sidewall would you put the mark? And what does doing this indicate?


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## morepower2 (Apr 19, 2002)

SR20 Who Knew? said:


> Where on the sidewall would you put the mark? And what does doing this indicate?


From the tread to the the rim. If the tire is not inflated hard enough, it will roll onto the sidewall and rub off the chalk, add air until the chalk is just bairly rubed off to the shoulder of the tread. This might be over 40 psi on a stock car.

Too much tire pressure and the chalk won't rub off at all. The chalk is a poor man's pyrometer.

Mike


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## RiceBox (Apr 30, 2002)

Just make sure you don't go too far over the max. pressure written on the side of the tire. For more fun, if you put MORE pressure in the rear, the car will rotate easier. Be warned though. I had 35 PSI front, 38 PSI rear on my B12 and it would almost spinout through the slalom. That was pretty much the limit. B13s will be similar, but i'm not sure about B14-15s


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## SR20 Who Knew? (Jul 29, 2003)

So should I run 40 PSI all around and chalk the tires, do one run and add or take away air accordingly?


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## morepower2 (Apr 19, 2002)

SR20 Who Knew? said:


> So should I run 40 PSI all around and chalk the tires, do one run and add or take away air accordingly?


Usualy 40 psi front and about 35 psi rear is a good starting point for a pretty stock FWD car.

Mike


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## Whisper (Jan 21, 2004)

Keep notes of the pressures your running. (makes it easier during setup - 1st run is correct)

I was given the advise to run 5lb less in wet weather. On a stock 03 spec V, that leaves 40/35 in wet, 45/38 in dry. I was still out to the sidewall roll point. (Conti)

You can also use shoe polish.


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