I'm getting a set of snow tires together and was wondering if there is any problem with non-stock tire diameters and TCS on the Z.

I know on my old CLS I had all sorts of different tire/wheel combinations on it and it never affected the VCS system, but, I've heard various rumors about this on the Z's.

 

I recall at least one person that had issues with TCS by using weird tire sizes. I'd try to keep them as close to stock variance as possible. I think the rule is no more than 3% between front and rear. Any more than that and the computer detects slip.

 

+1

It's been a while since I looked at my winter tires, but I think I'm running 225/45/17 Front and 225/55/17 Rear on ASA 17x7.5s per TireRack's recommendation. Seemed to work pretty good for me.

 

What about 245 front, and 285 rear? would that trip out the TCS?

 

You need to read up on how tire sizes work. The problem is not the width it is the diameter. So just stating tire widths means nothing. You need to keep a smaller diameter in the front and a larger diameter in the rear to keep the TCS happy. If you are outside of that range then it will sense wheel spin even though the wheels aren't spinning.

 

Ahh thanks for that info. King Tut, how about some 18's in the front, and 19's in the back?