tersian

Okay, I've been looking at tons of posts about backspacing and wheel sizes and the more I read and the more people who say they put a certain size on their C3, the more I get confused. Can anyone give me a straight answer on what is the largest size wheel/tire combo I can put on the back of a 81' with AND without relocating the e-brake bracket and what backspacing is needed.

TIA!

jac1502

I fit 18 * 8.5 wheels with zero offset and 2455/45/18 tires all the way around with no problems. Hope this helps

tersian

Wow, 18's! I'm kinda curious how wide I can go in the back with a 15" rim, and what my limitations are and if they can be solved with a bigger wheel.

MN-Brent

Front is 4 inch backspacing on an 8 - 8.5 inch wide rim. I think this is important for proper steering geometry.

Rear is 4.5 inch on 15-17 inch rims. You may need to relocate the E-brake bracket at this level. I have heard you may get away with 4.75 with E-brake bracket moved also.

If you go 18 inch rim, then the rim clears the E-brake bracket so this solves this problem. This is what I have seen from a post with 18inch rims mounted.

Just make sure your rim design clears the caliper also.

Brent...

tersian

What I'd really like to find out I guess is how wide of a tire can I run on the rear with a 15" rim and relocate the e-brake bracket and at that width, what would be the backspacing needed to clear the caliper?

tshort

I can't answer your question about widest tire or when to modify e-brake bracket but backspacing has nothing to do with clearing the brake caliper. It has to do with the design of the wheel. The rim mounting surface needs to be slightly inside the rest of the body of the interior of the rim. In other words, if you take your wheel off you'll notice the caliper sticks just past the mounting surface on the hub. I know that the TT II's just barely clear the caliper. Actually, they are so close that you'll see some wheels from them that do and some that don't. Mine are so close that some very minor grinding was necessary to clear them. They are actually so close that when I repaint the calipers sometimes some of the paint comse off.
Hope that helps.

macx

What are these TT's you mention and where can I find them? And what are some good sources in general?

I just got my (first Vette) 81 and am looking for wheels. Prefer at least 16's,
17's would be good.

Thanks!

tshort

TTII's are American Racing Torque Thrust II's. They had been decent wheels in the past but I've heard of people having problems with some of the latest ones. Apparently with the high volumes they are going thru the quality is starting to drop off. Edelbrock has some very nice wheels that are just like the TT II's.