Mark in Baltimore

Thanks, Greg and Bob. I have a set of 235/295 MPSC's in the garage and was hoping I hadn't made the wrong rear tire choice.

Bob, I usually run my rear MPSC pressures one lb higher than the rear. What does the four lb difference do?

Mark in Baltimore

Chuck, I assume he meant hot

Greg Fishman

I believe the MPSC's in the 265 285 and 295 widths were all the same diameter.

Mark in Baltimore

Really? So the aspect ratio didn't change even though the width increased? I hope so!

Greg Fishman

http://www.michelinman.com/assets/pd...otsportcup.pdf

Go to the specs portion and you will see the 265 has a 35 aspect ratio and the 285 and 295 have a 30. Overall diameter is a tenth of an inch smaller for the 285.

Mark in Baltimore

Damn, Greg, that's awesome. I loved the jump from 265's to 285's. I'm guessing the 295's will keep me grinning, too.

Thank you.

bobt993

32/36 seems to be the magic number. Starting temps? track condition, temp, and camber on the track itself. Try 27/28 starting front, 30 rear . Run them hard and slide the car early, trail brake extra on your warm up laps (left foot braking if you do) and really get the front end working. Come in hot and pit quickly. Have a buddy measure temps/pressures, bleed the tires to 32/36, go out, do it again, and one more time after a long session and not after the checkered, come in a lap early. Next day, check temps cold and write this down in your log book for the track conditions ie: 60deg, sunny, starting cold temps, tire sizes etc..... be **** about the tires. I am a complete convert over the last 2 years. PS. verify your gauge is very accurate. Lastly if this drives you crazy, buy a big bottle of nitrogen.

KOAN

Thanks. I keep a log of all of those things, and have been using 34/36 hot, but have tried everything from 32 to 40. I'm always curious to find out what other people are using, and will try 32/36 to see how I like it. I use 235/285, but am about to change set up...springs, shocks,camber, etc. I am also about to get a nitrogen tank, and am debating whether to use it just to top off (light tank, no stabilization advantage) OR A BIG HEAVY TANK. Can't wait to see the differences.

Bill Verburg

Rick, I'm considering the RA1s in the sizes you have formy '95 993. Can you provide the wheel widths and o/s that you have and where your clearance issues are?

My track wheels are 8 & 10 x18 MY'01 996 5 spokers

RickBetterley

Bill Verburg asked:
Rick, I'm considering the RA1s in the sizes you have formy '95 993. Can you provide the wheel widths and o/s that you have and where your clearance issues are?
My track wheels are 8 & 10 x18 MY'01 996 5 spokers
Hi Bill
Sorry for the delay in getting a response to you; I was under the car most of yesterday.
I have Forgeline WC3 8/10x18 with 245/40 and 275/35 shaved Toyo RA1s. Clearance is fine on the back, some very slight rub on fronts (against the lip) only apparent on the street, not on the track (according to previuos owner; my first track day is tis Friday).
I don't know the offsets unfortunately.
Hope this helps.