Recommended Pressures - BF Goodrich G-Force R1

[larrybard]

Just bought a set for my 1995 993 -- 225/45/17 front, 255/40/17 rear.  Tire Rack is not too helpful as far as recommended pressures, stating "37-43+" hot and 29-34 cold.

I know, ultimately, I'll have to see how the car behaves at any pressure while hot, and check the wear and temps, but any suggestions, particularly for approximate hot pressures for the front and rear (I can always, as they suggest, start out cold 5-7 psi below the target hot pressures)?

Thanks,

Larry

[scwaters]

I have a track prepared Cayman and i'm on my thrird set of R-1s (VIR, Summit, T-Bolt, Glen) My car weigh in at 3k and at any ambient temperature under 85 degrees I start mine at 28f 30r. Look for 36/38 when I hit the garage. After the first 8-10 heat cycles I end up dropping the fronts 1 to2 pounds because it starts to wash out a bit and this corrects it. I find that at around 28 heat cycles you have to play with the hot temp as they start getting a bit slippery.I

[larrybard]

Thanks, Sonny!

[Brian Minkin]

On Your 993 I would look for 36 hot when you come back in. At 38 the car will under-steer. I would start 27 front and 28 rear an adjust from there. These are the pressures I backed Bob Gilberg down to on the R-1 and the car improved drastically in handling compared to the tire rack recommendations.

[larrybard]

Brian, So I'm sure I understand -- your recommendation is 36 hot for both front and rear (as distinguished from Sonny's recommendation of 36 front buy 38 rear)?  Thanks.  Larry  P.S.  And maybe if I follow your recommendations I can become a crazy track speedster just like Bob.

[Brian Minkin]

Larry,

Yes on a 993 36lbs hot all the way around. (hot being when you are back in the padoock).  If you checked pressure in the pits mid session you would look for 38 all the way around.

[Bill Lehman]

I recently started running this tire on my Cayman S. At VIR last weekend, I found that Brian's recommendation of 36 Hot all around was about right.

[michael lang]

Larry, I'm curious, what were you on prior to this tire and what pressure readings were you getting before and after your sessions?

[larrybard]

Mike,

Apologies for the delay in responding -- and for the insufficient answer, both of which caused by my inability to find my notes (which I think got inadvertently erased from my BlackBerry).  Although Michelin PSCs weren't my most recent tires -- for some reason Michelin discontinued them in my size -- I think that I used to run them hot at 36R, 32F (but, obviously, regardless of what my notes might have said, I inevitably played around with the pressures depending on how they felt, whether my son and I were both driving the car in separate sessions, etc.).  Sorry that's not too helpful.  (And as for cold pressures, can't say I have any recollection at all as to what I might have reduced them to, from normal street pressure, just before going onto the track.)

Larry

[michael lang]

One thing that I do is keep a journal in my trackbox with various pieces of information. One of which is tire pressure readings, both cold & hot, along with notes about different stuff one runs into during a session. I would definitely recommend using one, that way you won't need to rely on memory what your readings were. The tire that you chose is a really nice tire, just out of curiosity, why did you chose that one over an intermediate like an NT01 or R888? Are you driving that tire on the street?