jfrc

I did a search, found little info, but not much detail on chalking tires prior to track time.
I have a practice autoX this wknd, and I am wanting to re-evaluate some things I do. I ran 2 yrs ago, was pretty fast (3 overall FTDs), but not always consistant.
I want to examine my tire pressure.
You are supposed to chalk some lines from the outside shoulder towards the center, then what?
After a pass, if chalk lines are too long, more or less air?

wtknght1

Don't waste your time chalking your tires. Spend $100 on a good pyrometer and take your tire temps after a run. That will give you a good idea of what you need to do with your pressures, alignment, etc. i.e. If the temps in the center of the tread are higher than the inside and out, then you're pressures are probably too high. Chalking really tells you absolutely nothing.

Aardwolf

With a new set of tires after my last HPDE, I could really see that I had a little to much air. The wear line was to high on the tread and the middle had more wear. There are small triangles on the sidewall up by the tread to show were the wear should be, on the tires I have. If I was to use chalk, I would mark the tire and look for the wear line to be using all of the tread. Not to high or to low off the side of the tread.

davidfarmer

If you are running a street alignment, chalk can tell you if your pressures are dangerously low. That's it. As Chris says, if you want to actually improve handling, dial in alignment/pressures, you need temps.

I have an infra-red, standard probe, AND a 12-point memory pyrometer depending on where I am. Infra red is great if there are tight corners just before pit-in, and the car comes in hot. Probes are good all of the time, as you get a good read of the stabilized chord temps.

bty, a memory pyrometer is around $300 or so, but worth it if you spend much time at the track.

Z06 Whisperer

Are you doing low speed or highspeed autox's? I found sometimes, unfortunately, my tires didn't get warmed up enough during the time I was on the course to maybe make it possible to get accurate tire temps. I started out doing the chalk thing to and agree it's not the most reliable method. I did the "three lines chalk extending from the wall of the tire up and over the edge of the tire in three equally spaced areas method" I think in part this is supposed to show if you tire is rolling over thus indicating an underinflated tire. I found however the chalk could get worn off if you run up on the sides of the track and such with your tire. Grabbing air pressures quick after getting off course and doing a visual inspection of tire wear might help too (other low tech methods ).

jfrc

not too many high speed events around here- usually TMS or TWS, sometimes Hallet
most are lowspeed, what we like to call fast lowspeed (not too tight, get to use more than 1st and 2nd gears for a change)
there is a club member with a pyrometer, and is always playing with, checking track temps, engine comp, cabin temp, whatever
i'll make a few consistent laps and borrow it from him