Will these fit a 4th gen without a BFH? I think they have a 65mm offset which would normally be to much for a 9.5 in wheel, right? I found this article where they are on a firebird and they fit fine: "The wheels fit perfectly," says Murphy. "The offset was just right. Those wheels look great on an F-car."

http://highperformancepontiac.automo...ion/index.html

 

Are you using them in the back only, or on all 4 corners?

In the front, 56mm works on a 17x9.5" wheel. You will probably get away with a bit more offset (= more backspace) on an 18x9.5" wheel, since as you move further from the spindle, the steering knuckle is curving inwards toward the engine. Whether the spindle curves back enough (0.35"), I don't know. The wheels will sit deep in the wheel well.

In the back, it shouldn't be a problem. The backspace is ~7.78", and that's about 0.15" less than the sometimes problematic 7.93" backspace ZR1/GS wheels.

Gonna be close.

 

If that's the actual offset of your wheels then you'll need a 20-25mm hub spacer, which will set the wheels out far enough but not give you any problems(effective offset of +45 w/20mm hub spacer, and +40mm w/25mm hub spacer).

 

Ok, thanks.
I was planning on using the 18x9.5 on all four corners since i found some brand new wheels for $250 each. Seems like too good of a deal to pass up and i love these wheels....how reliable are spacers?

 

Before you go buying spacers, mount the wheels and see how they fit and look. If you decide you want to push the wheels out 1" for a more aggressive look, you wouldn't buy a "spacer", you buy an adapter that bolts to your wheel studs, and has a 2nd set of studs that the wheels bolt to. For years I've recommended Skulte for those adapters, but thye have ceased production.

 

You want something like this if your post wheel offset is correct.
http://www.importrp.com/files/images...drm-spacer.jpg

BTW, H&R makes good Hubcentric Hub spacers in a 20-25mm sizes.

 

Where is a good place to get H&R wheel spacers, or wheel adapters? Lots on ebay, but not sure of the quality?

 

i was able to finally find some spacers/adapters, thank you to everyone for your help in answering my questions

 

Post some photos up after you get everything installed.

 

actually, i finally decided not to get the wheels because i didnt feel comfortable using 4 spacers. but.....i just ordered some centerline retros which i will post pictures of when they are on the car!

fyi: smcperformance.com has 8 18x9.5 brand new never mounted C5 magnesium wheels for $250 each