Is anyone tracking their 928 running the 18 x 8 and 18 x 11 with the 225's up front and 295 or larger in the rear? If so how is the car handling? I'm wondering if such a huge size disparity from front to rear is causing some serious understeer or other handling issues. I can understand these sizes on the 911's with their weight biases, but the 928's balance is quite different.

 

one time on track in the S2 when it was an auto with hollowspoke turbo rims and 235 on the front, 315 in the rear (street rubber) i was driving it hard enough to keep up with the S4 cars, encountering antilock under braking etc and found that the rears would still tend to get loose more often than the front. one advantage of the big rear tyres is that they catch again (in the dry)!

 

I'm running 255/17 in front and 275/17 in the rear. I have my front Konis soft and the rears about half hard. The car is perfectly neutral on the track. YMMV

 

What you do with the brake pedal and gas pedal has more to do with understeer and oversteer than the tire sizes plus the way you turn the steering wheel to enter the "turn" is critical to handling. The 928 on street rubber is ALWAYS going to understeer unless you get on the gas pedal and create power oversteer. All of which is a moot point since if you have to THINK about what you are doing it is never going to happen much like riding a bicycle and making a turn there is no substitute for PRACTICE /track time. Basically 225 front tires are going to understeer at about the same point if the rears are 225 or 315 unless you fit a tight limited slip then it will understeer worse !

 

I"m using PS2 18x265's front w/18x295's rear (Tread Wear=130)... seems pretty neutral w/a fairly tight lsd, bilstein/ebaich/poly bushings, etc... like jim said, to me it seems to be a matter of technique and throttle control more than tire size as long as the tires are fairly comprable.. w/the goodyear (TW 330) rears and ps2 fronts - it was a really squirrelly SOB though, so don't mix TW ratings too much or strange things seem to happen more easily

 

At track days in a 1986.5 928S, AT, the car feels extremely well balanced with the above tire sizes. No oversteer unless I induce it and no pushing. Running Goodyear GSCS DOT legal track tires that work very well. I've gotten these same comments from the DE instructors who have to drive your car during the first lap or two when I was climbing through the different DE levels to Solo.

Missed the last few track days due to a full rebuild of the trans and putting on a 1989 differential. Other smaller stuff and now ready to get back on track!

Constantine