Doing my first track event with the new to me 07 .1 RS. Question on hot tire pressures on two tires.

1. Michelin super sports- what is hot pressure and where do you start when cold.

2. Corsa - same questions

Thanks
Tal

 

Cold depends on ambient temperature. I ran them this weekend at Sebring and found that 35 all around worked well for me. Be warned, there was a pretty steep curve. Cold tire pressure was 27psi leaving the pits with an ambient temp of ~65 degrees or so.

Don't run Corsa system, so, can't help you there.

 

I have followed these instructions and been happy with the results:

http://www.tirerack.com/tires/tirete...nd_Feeding.pdf

 

The document you link is for the Sport Cups. The OP had questions concerning the SuperSport - completely different animal...

 

You're correct - I read too fast and didn't realize he wasn't using Cup tires. These pressures would be way too low that are recommended in the PDF.

 

I run SS 38-40 hot. Start 8psi cooler and bleed off after your first session. You don't want to run them too cold or too hot. After your first session they should be good for the rest of the day.

 

+1 Michelin recommends you start with the OEM cold pressures, I would not run them more than +8 hot... a cheap tyre pyro or the old "chalk" test will help keep the tyres at the appropriate pressures...

 

Not sure what the chalk test is, but the pyro showed even temps across the entire treadblock at these pressures. I do have a fairly aggressive alignment though.

 

How much pressure gain you experience is related to your experience and style of driving. Some people gain 10 to 12 lbs of pressure during the first session, others will only gain 6-8 lbs. Check after every session. As the day and pavement warms up with the sunshine, so does you tire pressure. As for the tire hot pressures: front 35 rear 37-38 for PS2. No actual experience with Super Sports. They didn't exist when I ran street tires.

 

chalk test is a quick way of determining if the tyre is over/under inflated (and rollling over the shoulder or not) ...

basically you draw a number of chalk lines approx 2" across the shoulder of the tyre (perpendicular to axis of rotation) ... take a lap, observe the chalk marks, if the chalk a across the shoulder, if there is still some chalk on the contact patch, your tyres is overinflated, if there is no chalk on the contact patch *and* some has been erased from the sidewall, your tyre is under inflated ... if the chalk is absent from the contact patch but remains on the sidewall the tyre is properly inflated...

its not "accurate" but its a good approximation if you dont have a pressure gauge and/or tyre pyro ... or cant be bothered to use both ...

 

Interesting. Crude, but it makes sense.

 

I have seen a couple of tires with markings already from the factory on the tire. I believe RA-1s have the "roll-over" mark on the side wall. It looks like a horizontal line with an arrow pointing up to it. If the amount of "roll-over" wear meets up with the line, then you have them properly inflated.

 

I used to run the RA1 when I could get them. I always wondered what that arrow was for. What a great tire. Wish we could still get them in 18" porsche fitments.

 

On the Onelap of America car which is a heavy GTR.. We run 36 hot.. I would say 35 would be a good area for hot pressure on a GT3..

 

Really is a great tire. Ran them before switching to a set of R888s, couldn't stand them. Threw another set of RA1s back on.