Quote:
Originally Posted by lutzdog
no the sizes are the same all the way around. when the vehicle was bought there were z06 rims the same size all the way around.
interesting. so all that would cause internal errors and steering sensor errors?all the stuff i have been experiencing?
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The steering sensor could be a fluke, but is probably not related.
Here's how traction control works. There is a wheel speed sensor located in each bearing/hub on the car. These sensors are used for ABS as well, but for the sake of traction control, it compares the difference in wheel speeds front/rear.
In stock configuration, the rear tires are about 1" taller in height compared to the fronts. (Not just wheel dia, that is irrelevant, but overall diameter of the tire). Because the TC system is programmed for those tire heights, it "expects" to see the rear tires always turning slightly slower than the front. (larger diameter turns slower).
When TC does engage, it does two things, it applies braking to the rear wheels, and also severely retards engine spark timing, thus noticeably cutting off the power, until it senses traction is restored. This compounds the problem in a case like yours, as you never did lose traction, so restoring it is kinds of difficult.
So, giving an example of a more extreme situation than yours, say putting a taller tire on the front than what's on the rear, is a surefire way to run into unintended TC engagement. The TC logic "sees" the rears spinning noticeably faster than the fronts, and thus thinks the rear tires are spinning.
You, running same size all around, seems to be the borderline point where the problem randomly occurs. Some people claim to do the same and never have unwanted TC engagement, others have the same luck as you are having, and find it does occasionally falsely engage.
As Sneaks already alluded to, the "rule of thumb" is to keep the rear tires taller than the fronts. Even 1/4" taller usually works fine, but I always recommend at least 1/2" taller, just because tires are not cheap and I'd rather not suggest a size combination that could potentially be problematic to someone.
If you are running a 17x9.5 all around, going to a 255/40/17 size on the front (with the 275/40 on the rear) would probably solve your issue.
Finding a pair of 18" Z06 wheels for the rear would be another option, and open up more tire choices for you as well.
And, in the meantime, until you do figure out a permanent solution, simply shutting Traction Control off will at least prevent it's unexpected intrusion and power loss during your drive.
