Quote:
Originally Posted by DocDirk
Thanks for your replies guys! The Roger Krause chart boggles the mind...... I guess having reviewed what I've learned so far it comes down to two questions for me.
All other things being as equal as possible;
1. Is there an intrinsic "autocross" turning advantage to the 245/275 combo vs 275/335?
2. Does the heavier weight of my car influence the above choice significantly (2400 vs 2800#) ?
Ride safely!
Dirk
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I use 295x30x18's front and 335x30x18 rear for autox with good results, if I were doing it again I would have installed 315x30x18 fronts. As stated elsewhere there are so many other variables that you just cannot just assign a tire size without all the facts: Roll stiffness front and rear, roll axis, chassis stiffness, aero loading, suspension geometry, track width and weight distribution all can effect tire width decisions. I use the same tire sizes for road courses with a change in rear springs (from 1100 down to 1000 lb/inch) and the car is perfectly balanced with a trace of understeer under throttle.
The car is not harsh at all and uses a good portion of available suspension travel when running, car weight is 2350 with a 53% rear weight bias.
As far as street tires go I would have to agree that you don't need to go really big on tires sizes, the big ones cost more and will just get you in more trouble if something goes wrong because you will be going faster when it does.