Track tire psi

[strokeoluck]

I'm heading up to the track for the first time later this month, forgive any stupid questions from this rookie. Can the track guys tell me what psi I should start the day out at? And after I get done with a 20-25 minute session and (I'm assuming) the tires get hot, should I adjust the pressure? Any other words of wisdom for my first day at the track?

I've read up as best as I can on the race track website, and also have a buddy who races his Cayman quite a bit, but he can't help me with this BMW-specific tire question.

Thanks!

[i2ichal2dZ4M]

I adjust and keep my psi around 33 all day.

[Kgolf31]

Adjust your tire pressure accordingly to the roll-over on your arrows.

After a HPDE session, the tires will cool down so unless you're adjust mid-session there is no need to adjust tire pressure

[strokeoluck]

Originally Posted by Kgolf31

Adjust your tire pressure accordingly to the roll-over on your arrows.

Huh?

[pal]

Monitor sidewalls post every session as Kgolf31 mentions and adjust up down as needed based on the arrows on the tire.

Be aware on track when grip starts to fall away and back off for a lap or so to see if it comes back. Then check the pressure as soon as you get into the pits post session and adjust.

As a rule of thumb, I start out at 31psi for most events and fine tune as the day progresses.

[johanness]

Originally Posted by strokeoluck

I'm heading up to the track for the first time later this month, forgive any stupid questions from this rookie. Can the track guys tell me what psi I should start the day out at? And after I get done with a 20-25 minute session and (I'm assuming) the tires get hot, should I adjust the pressure? Any other words of wisdom for my first day at the track?

I've read up as best as I can on the race track website, and also have a buddy who races his Cayman quite a bit, but he can't help me with this BMW-specific tire question.

Thanks!

Check out the track section here on Zpost. Lots of people who asked many of the same questions on their first time out (myself included). Good resource.

Have fun!

[seank]

It very much depends on the tire and size, but we can give a safe rough estimate if that is what you are looking for?

[strokeoluck]

It's sounding like 32 +/- is a good ballpark number. But I'm still very confused by these other comments, such as "Monitor sidewalls post every session as Kgolf31 mentions and adjust up down as needed based on the arrows on the tire."

What arrows on the tire? And what are they going to tell me? All I really know about tires is to stick a gauge on the stem and check the psi. After that, I'm lost.

[sipman]

If you get white shoe polish in a bottle, you can dap it on the edge of the tire where the tread and sidewall meet. After your drive, the missing white will show you how much your tire rolls over, or deflects under lateral load. Alternatively, there are tiny arrows molded into the tire at the same spot which may be able to show you the same thing.
If you have a harbor freight near by, buy an infrared thermometer. After your first run, and each additional run, measure the outside,center, and inside portions of the tread. If the edges are hotter than the center, add pressure. And vice versus.
If you run a lot of camber, you might notice the inside is the hottest, then the center, then the outside. That's what you want... The progression of temps.
I run hankook rs3 tires, with a 46 front and 44 rear. These tires love heat though. If you are on regular street tires, these pressures may be too much for you and the tires may become greasy as they get hot.
My advice is to get the thermometer as most people starting run too little tire pressure, which means the edges of the tire do more work(are hotter), and wear faster than the center. $30 on a thermometer beats having to buy a set of $700-1000 tires because you've worn the edges to cords, especially when there is plenty of tread in the center.

Good luck

[strokeoluck]

Ahhhh, got it, thanks Sipman - and to all.

[MFGJR]

I think some guys here are talking cold pressures and others are talking hot...

Spring/fall-type ambient temps, I'm going out at 30F/28R cold to keep my Star Specs under 38 hot--any more and they go greasy about half-way through a session. (I get real-time pressures from an aftermarket system.) I've had to decrease cold temps as I've gotten faster over time.

I'd suggest starting at 32 and after the first session or two add a little pressure if the tire is rolling over past the tips of the little arrows (as discussed above) to ensure you're not hurting your tires. With this being your first event, don't worry about optimal pressures beyond that--you'll kinda be overwhelmed with other stuff.

Have fun, be prepared to join HPDE Anonymous!

[seank]

My advice is to get the thermometer as most people starting run too little tire pressure, which means the edges of the tire do more work(are hotter), and wear faster than the center. $30 on a thermometer beats having to buy a set of $700-1000 tires because you've worn the edges to cords, especially when there is plenty of tread in the center.

As he said. Knowing the tire temperatures across the tire is best, but remember that they cool down quick and that is why people briefly pull off and have someone check the temperatures for you.

But seeing that this is all new to you, stick to to the shoe polish method for now. Different tires do better at different temperatures as well to complicate the matter.