996 tire wear problem
#16
Rennlist Member
Also, FYI, 40 psi hot is way too high for Z214's with 1000 lb springs unless your car weights 3700 pounds...
#17
Instructor
Thread Starter
Although I had the identical problem with the R6s at 35-36psi, your comment relating tire pressure and spring rate and vehicle weight is interesting. Can you elaborate?
js
js
#18
Rennlist Member
The Z214 operates really well at lower pressures thhan most folks expect, depending on vehicle weight. When we run too-high pressures, especially with heavy spriimgs, the tires significantly increase the perceived effective spring weight. In addition, with negative camber, the car effectively rides only on the inside of the tread. And with heavy springs, on hard throttle, this can be further exacerbated when the rear wheels will sliightly "bounce" due to not enough compliance. All of these factors can significantly increase inside tire wear of the drive wheels.
Beyond thatt, use a probe tire ppyrometer to help set best pressures (and camber). But I have found thhat on my 3000 lb (with driver) M3 race car (750 front springs, 850 rear), on most tracks, I am starting my Z214's at around 22 froont cold, 24 rear cold. Draw your own conclusions about what those translate to hot.
Beyond thatt, use a probe tire ppyrometer to help set best pressures (and camber). But I have found thhat on my 3000 lb (with driver) M3 race car (750 front springs, 850 rear), on most tracks, I am starting my Z214's at around 22 froont cold, 24 rear cold. Draw your own conclusions about what those translate to hot.
#20
Rennlist Member
Best bet is to borrow a probe tire pyrometer and test various HOT pressures in pit late, to see how the temps spread across the tread. I am not sure what ytour car weighs...and remember, mine is FRONT engined, so you may want more starting pressure in the rear than I use...