Track Tire Type and Width

[Acid_J]

My front 17 rims are only 7" wide so 245's would be too big...for you 245's would probably be fine. 245's are recommended for a 8-9.5" rim (on the toyo website anyway)...

[986chris]

? are new shaved tires better than old tires with same tread depth. i'm thinking mostly of side wall performance.

[Acid_J]

sorry...I can't give you an expert opinion there 986chris....I would imagine as far as grip you would probably do better with new, shaved tires but for sidewall my WAG is that it would be the same.

[racer_d]

Originally Posted by 986chris

? are new shaved tires better than old tires with same tread depth. i'm thinking mostly of side wall performance.

The reason for shaving a tire is to reduce heat build up and tread squirm. Sidewall flex is not affected by shaving a tire or not. Now, another thing to consider in an example

1) you run brand "X" all last track season.. lets say you subjected it to 40 heat cycles.
2) you get brand new set of brand "X" tires, shaved.

Which is better? Well, it is possible that brand "X" has "heat cycled" out of its useful period even though it still has useable tread. If this is the case, then the newer tire will provide better grip, simply because it hasn't been heat cycled as much.


Oh, and as someone asked before, 245s are too wide for a 7" rim. if you already have an 8-8.5" front rim (or maybe all around) 245s would fit fine. Plus you could balance out the wear by rotating tires front/rear, left/right.

[986chris]

So do street tires "heat cycle" in daily use or is it in just exteme use. And is there away to measure "heat cycles" that a tire can withstand before reduction in performance. Should you use new tires on track first or "vice-versa".

[racer_d]

All tires experience a "heat cycle" A heat cycle is just the heating up and cooling down of a tire. Now, would you notice degradation on an all season on a camry? not likely, because neither are performance oriented. But over time (age) and use and tire composition, you might notice that the tires on the Camry are not as good in the dry at 30K miles as they were when almost new.

Lots of racers keep all types of data and keeping track of the number of heat cycles a tire is put through is one of them. They will also notice when a tire is "off" compared to a new one. Racers might use an "old" or heat cycles tire in practice, but if available, they would put on new ones (stickers) or just scrubbed in ones for a qualifying session to be a little bit quicker.

Since racers often keep so much data, they will learn that given similar conditions, a "new" tire might be several seconds per lap faster than an older tire that has been heat cycled beyond usefullness.

[boxster or briefs]

I asked a similar question regarding tire selection for daily street driving and track/autox use. Many recommended R888's. According to SportsCar magazine, the magazine for SCCA members, i think it was January's 2008 issue mentioned Bridgestone had the most wins of all other tires for the SCCA races ending the year 2007. Look at the Potenza &/or g-force series.

Furthermore, Michelin makes a good track/street tire with good treadware called Pilot Sport Cup. The last autocross race I did a guy in a 2007 Boxster set the best lap of the day in his class with Michelin PS2's. Lastly, Yokohama Advan Neova AD07 series I hear are decent too but I have not tried them yet. Good luck

[steve00s]

I have been driving on Falken Azenis RT-615's for the last year and they have been great autocrossing and at the track. I have also driven daily on them. Grassroots Motorsports magazine continually rates them as the best autocross tire. At non-Porsche events you see alot of them but I've yet to see them at a Porsche event. 225/17 in the front and 255/17 in the back fully mounted for $650. I'm due for another set soon. Is there a better deal? Anybody have any negative experience with these?