: 9.5 inch factory wheel?

10-20-08, 09:14 PM
I have a 2005 CTS-V that, as you know, has runflats. I decided to pick up an extra wheel and tire so I'd have a spare. I picked up a nice chrome, GM-stamped CTS-V wheel but measured it and it's 9.5 inches wide. Factory wheels are 8.5 inches wide, right? What gives?

Simple question, I know...

10-20-08, 09:20 PM
8.5 rated and 8.5 measured are different. Factory is 8.5". Measure the face and tell me it's a 18".

10-20-08, 09:22 PM
no... it's 19.5" diameter

but then again so are the wheels on the car right now. I see what you mean "rated" at 8.5" vs actually BEING 8.5 inches...

So I'm good.

10-20-08, 10:50 PM
I did that many moons ago with a set of 17s, and was like wtf? Glad I could help.

10-21-08, 12:11 AM
The advertised wheel widths for all wheels is bead-to-bead, not lip-to-lip. Most wheels have roughly 1/2" lip outside the bead on the inner and outer face of the wheel, so when you measure lip-to-lip they're typically about 1" wider than advertised. I've measured a number of wheels over the years and found they range from 7/8" to 1-1/8" wider than advertised.