I have an out of round wheel which appears to be the cause of a mild vibration, so I just obtained a set of wheels (same width and offset) with serviceable tires that were taken off of a
981
. The tires are the same tread width with a 40 profile instead of the factory spec which is 35, so the overall diameter is nearly an inch greater. I would like to find out if the wheels solve the vibration issue without dismounting and remounting the 35s onto the new-to-me rims. Is there any negative consequence to running a slightly oversize diameter tire?
Your speedometer will read lower than your actual speed, but not by much (when the speedometer reads 60, you'll actually be going a bit over 62, and so on). Otherwise there shouldn't be any negative effects that I can think of.
I understand the increased overall diameter will make the speedometer indicate lower than actual speed. My bigger concern is reduced clearance. I did put the wheels with higher profile tires on the car, and my vibration issue has improved. The larger tires have some tread life remaining, so I was thinking of running them on the track until they are used up. And yes, I recognize that the larger diameter and weight will be detrimental to my acceleration. But I just want to confirm that they won't have clearance issues under hard braking and cornering.
Not sure about that, but it seems pretty unlikely; the diameter of the rear tires is an inch larger than stock, which translates to the outside of the tire being 1/2 inch closer to anything they might come in contact with during hard braking/cornering, and the front tires are .9 inches larger than stock, so .45 inches closer. (The width of both fronts and rears is nominally the same as stock.) I think the only way to know for sure is to try them and see. If there are clearance issues, I doubt they'd be enough to cause a catastrophic failure. You might want to try them in an autocross context first; if there are issues that cause you concern, at least it would be less of an investment to find out.
It may sound silly, but are the wheels (not tires) the same diameter as the bent wheel?
Yes, the bent and true wheels are both 19-inch (and 8-inch width). The tire on the bent rim is 235/35-19 and the one on the true wheel is 235/40-19, so the calculation by
@Kevin CS
is correct.
willtheyfit.com will give you ALL the data about the changes you are making.
