mdbickell

I posted this in the comp/racing forum and haven't had any responses yet. Hopefully someone over here can help me out...

I couldn't get my toyos in time so I'm running yoko advan a048's for the first time this weekend on my SC. Any suggestions on tire pressures?

thanks,
Matt

Jim Michaels

I have never seen any tire pressure recommendations for the 048's, but I'd like to hear what you think about how they perform after your event. You could call Tire Rack and ask them. Maybe the recommended pressures for the 048's are the same as for the 032's. If I couldn't find out anything specifically, I think I would probably try to set them cold to reach 39-40 psi hot. I'm a simpleton, so I classify the R-compound tires I've used into two groups; those that like hot psi 39-40, and those that like hot psi in the mid-30's. The Kumho Victoracers fall into the higher hot psi group, and the Michelin Cups fall into the mid-30's psi group. If the 048's start to feel "skatey" at 39-40 psi hot, you can try them a few psi lower for the next session. What someone else recommends is only a rough starting point anyway, as different drivers like different feels; skatey actually being fast, though a little scary.

Lennart

So I have just recently bought a set of Advan 48 tires for my 86 Carrera. These are my first competition style tires after running on mostly OE tires. In any event, had a tough time getting any pressure information from any one source (guess no surprise for experts out there - no shortage of them and opinions..). Tried Tire Rack and got no response via e-mail. called Yokoma directly after going to their Website. Talked to their rep who said that the best they could do was do calculate the normal 'street' pressure for it and would not give me much/any info regarding track/HPDE pressure - found that ironic. They later contacted me and put me in contact with Track Side Performance. They recommended between 32-35 hot. This would be for both front and rear tires. I had assumed (incorrectly) that somehow that the original spread between front (OE at 29) and rear (36) of 7psi would be maintained at the track but he did not recommend that but rather that both axis be the same.

Any comments on that?

My own experimentation over three track days had me come back (Hot) with Front 34 and rear 40/41. Rear felt 'skatey' at that rear pressure - early part of each session more grip and last few go arounds noticely more slippery. My own in experience did not clue me in (as did the earlier posting) did that skatey can actually be faster. But at these Hot pressures I did not think i was getting the most out of the money so now i will go back and try to dial in to the 32-35 range on both front and rear and see how that turns out. I'll check back in after May 10th..

Jim Michaels

Lennart: Thanks for your feedback on the 048s. What Track Side told you sounds reasonable, and would place the 048s in my simpleton's mid-30s hot psi category of R-compound tires. Your skaty experience with rears at 40 psi while fronts were at 34 seems to support their recommendation for mid-30s hot pressures front and rear. I'm no tire pressure expert, but I certainly wouldn't advise maintaining the 7 psi front to rear difference at track or autocross. That recommendation for OE tires is for road driving and helps to insure that the car maintains it's natural tendancy to push or understeer, which they consider a safer bias for most drivers. I use about 33 psi cold in the front even for road driving. Since the rears usually gain more psi on the track than the fronts, some drivers actually set the fronts a little higher than the rears cold in order to get both ends to similar psi hot. While some advanced drivers like a little oversteer and can be faster (and have more fun) with it, any more than slight oversteer reduces my level of confidence and probably slows me down. Thus, different drivers prefer different feels on track. I happen to like a neutral feel, where each end starts to lose grip and slide at about the same lateral force.

Lennart

So reporting back after trying the tires at Thunderhill (Northern California) at a midweek event with NASA (great time - 7 sessions plus extra session at the end - exhausted but such a blast). Ironically enough - in the recent past I had a tough time talking to another 911 owner with the same Advan A048 tires..but this time, where I parked I was literally surrounded by three other cars with the same set up. Sheer luck. In any event, I set up to come back with 35 hot front and same back at the first session - much better than in past, but still somewhat skatey at the end of the session. Next session came back at 32/front 32/rear and now really getting sticky. Talking to my "neighbors", two recommended 28-30 range hot front and rear and one 32/32/hot. I tried 30/30 next time out and wow, it was really good. 30/rear/hot and 28/front/hot next session out was not quite as satisfying. SO a long way of saying that for my driving skill (HPDE3 with NASA; about 18-20 track days), an -86 Carerra 911 with stock suspension, 30 front and 30 rear hot worked THE best. Weather was gorgeous - mid 80s and not a cloud in the sky. Life was good..

Jim Michaels

Thanks for the report. Good that there were others close by to help hone in on good cold/hot pressures. I was somewhat surprised to hear that 30/30 hot worked best, as that would mean starting cold pressures very low indeed. Starting with cold pressures close to 20 psi would give me pause, although I start the Michelin Cups at about 27 psi to reach about 35 hot.