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Tyre pressures for the track?

4K views 19 replies 13 participants last post by  Dirtboy 
#1 ·
Im planning on going to a track day in a week or so and was just wondering what to do with my pressures :dunno:

Do I increase them to 'full load' settings or lower them as the heat build-up increases pressures??

Thanks for any advice!

E46 325i on standard 205/55/16 's
 
#9 ·
I have the same question but I have 330i w/ Sport package. Street pressures are 39 front and 46 rear. I have tried 39/40 hot with ok results. Tires are 225/45-17 front and 245/40-17 rear. I have the original conti's on the car. Thanks
 
#11 · (Edited)
on 225/50/16 all around (Hankook RS2 Z212)

I'm at 36 front and 39 rear. I'm not 100% satisfied with the handling though.

I'm debating on trying the chalk 'trick' to see if i need to bump the pressure or not.

You guys have any suggestions?


EDIT: I should mention why I am not 100% satisfied. The oversteer on the car. 41 psi was too much pressure (according to the arrow on the sidewall - if you don't know what I'm talking about, I'll explain). now 38-9 and I feel the ass is even more loose than before, but the arrow indicates that the pressure is perfect.
 
#12 ·
Buy a pyrometer (about $100) and check the pressures (outer, middle, inner) on all four tires when race-hot and you will know how the track and your tires work together. Too much pressure makes the tire bow out in the middle so the middle will be hotter. Vice versa as the edges will be hotter for not enough pressure. The works better than chalk, but there is nothing wrong with using chalk.

Write everything down when you measure the temperatures so you can make the 12 measurements quickly, as soon as you stop racing, and so when you look back at the course you can correct for left or right corners predominating.

You can also set camber with a pyrometer but sometimes too much toe makes the numbers look odd.
 
#13 ·
This is what I will do, although it can be a bit time consuming to unbuckle the harness, disconnect all the helmet wirings, climb out of a seat bucket, rush to the tires and start the manual logging process. During the process the tires would have cooled. But data still helpful nonetheless.

Unless one has pit crew. :p

Tom Busby said:
Buy a pyrometer (about $100) and check the pressures (outer, middle, inner) on all four tires when race-hot and you will know how the track and your tires work together. Too much pressure makes the tire bow out in the middle so the middle will be hotter. Vice versa as the edges will be hotter for not enough pressure. The works better than chalk, but there is nothing wrong with using chalk.

Write everything down when you measure the temperatures so you can make the 12 measurements quickly, as soon as you stop racing, and so when you look back at the course you can correct for left or right corners predominating.

You can also set camber with a pyrometer but sometimes too much toe makes the numbers look odd.
 
#14 ·
Mr Paddle.Shift said:
This is what I will do, although it can be a bit time consuming to unbuckle the harness, disconnect all the helmet wirings, climb out of a seat bucket, rush to the tires and start the manual logging process. During the process the tires would have cooled. But data still helpful nonetheless.

Unless one has pit crew. :p
Helmet wirings?
 
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