:bigroll: An offset increase of 10mm per tire results in a front track width increase of about 3/4". The tire rolling center remains at the same location fore and aft, as the center cannot be moved "toward or away" from the firewall. Iwould be very wary of 1. Aftermarket wheels, unless you know exactly who made them and obtain an ironclad warranty. 2. Deviation from the factory wheel offset. The bearing capsules are stressed for the OEM wheel and nothing else. Greater offset places extra stress due to longer fulcrum distance. Personal opinion (biased...) The OEM wheels look better on the car......most aftermarket wheels are "too much...." You probably wouldn't notice a great handling difference....BTW, is your STS a late '02 with MagneRide???? If so, you have another body stability input to reckon with...
Look at the stickers under the spare tire cover. There will be one with a lot of 3 letter/number codes on it. This is the RPO (regular production option) list. The definitions can be found by doing a search at the top of the Forum page or in the specifications section of the FSM. MagneRide is RPO F55, and usually appears after build date 11/01, which date can be found on the sticker on the driver's door. That sticker will also give you the speed limiter specification by reading the tire description: Z or W=150 mph; H= 130 mph, and S=118 mph. All depends which optional tire/rim package was ordered with the car, and you can't change it (the limiter). (BTW, some tire/rim packages call for differing strut/shock/offset packages, and, the isolated letter/number codes at the lower area of the RPO list define the paint package used.)
Thank so much once again for the all the great info!
No F55 only F45 so it looks like I have CVSS? I wonder why the ride is so much firmer than my 99? Could it because my 99 has 16" tires and my 2002 has 17" tires?.
Also cant seem to find my paint code on the label. Next to the BC/CC it is blank.
I was expecting to find 3 digits and a letter,
Decoding some of the numbers 54U comes back with Exterior paint color Colima Grey Met (04) (Brazil)
Is this 54U the GM code or is this the "real" paint code?