jwt1603

I've heard conflicting opinions on this and searching the forum didn't help much.....

The question is, as long as a set of wheels clear everything on a C5 does that mean they will always work on a C4 also?

The reason for the question is I'm changing my track only 94 to CCWs this year and I'm having a hard time finding used 17s so I'm thinking of going to 18s since they seem to be more readily available. Specifically I'm thinking 18 X 11 in front and 18 X 12 in back. I want to go to at least 11s at all four corners.

Also, when measuring offset, is the proper method to put a straight edge across the back of the wheel on the outer lip and measure the distance to the flat mounting surface at the hub face?

I don't really want to spend the money on new ones since they are for the track only but it's looking like that's what I'll have to do.

Thanks.

Sidney004

TTT
I want to read the answer on this one as well. The 18" scrubs are becoming much more plentiful as well. I wonder if any of the Pirelli Grand Am 18" scrubs will hit the market soon.

Mojave

I'm running 18x10.5 C5 Z06 rear wheels on all 4 corners of my C4. They fit perfectly and don't stick out at all. C4's GENERALLY have more wheel well space than a C5, especially if they aren't slammed. So, I'm going to guess they will. I also run 17x11 50mm offset on all 4 corners, and they work well.

jwt1603

Thanks.

Sidney004

What tire size are you running on the 18's?

Gray Ghost GS

I sold my stock C5 wheels to a C4 owner and they worked great. He sent me pics - looked real sharp! However, once you go wider than stock Z06 wheels - all bets are off. You'll then need to verify fitment, etc.

Mojave

315/30R18 Falken Azenis. I run them for my local street tire auto-x class.



More pics here: http://mowhineracing.com/ch18.html

Sidney004

Chad:
When is your car going to be running again?

RAFTeRACER

I thought that any wheel that fit on a c-5 would work on a c-4 and I borrowed a set of 18x12 ccw's from a friend to use up some 335 scrubs that i had. When on the car they hit the trailing arms. I put on 1/2 in. spacers and seemed to have enough clearence but after a 20 minute session the trailing arm mount cut a 1/4 in. groove in both tires. Probly would have worked with 315's but don't know. I normally run 17x12 ccw's but they stick out of the wheel wells further than the c-5 wheels.

Mojave

That is a great question. I have a stock short block that needs freshening up and my heads are at Lloyd Elliots being fixed/ported. I need to take the bottom end I have to the machine shop and figure out what it needs before doing anything else.

ScaryFast

It needs more c.i.

Mojave

I'm with you 100%. 383 or 396 sounds like a good start to me. Sadly, I will never get it back on the road if I start spending that kind of cash on the bottom end. It will most likely stay a 350/355 unless I win the lotto.

Lister

Early C4 wheel offsets are different than later C4 wheel offsets so be careful. You can search these forums for the specs but I recall the early ones are 32mm and the later are 50mm with the exception of the ZR1 which I think was also 36mm.