Can you guys help me out with offsets? I've been taking measurements and calculating for hours and can't quite figure it out. On paper it looks like I'll need a spacer to get it perfect but I'm totally against it. Was hoping you guys could post some side shot pics listing wheel dimensions. I'm interested in 10.5 wheels possible 11's but don't want the tire hanging out what so ever. Thanks guys any help would be greatly appreciated. Hate to eat a set of wheels

 

The stock 9.5s have a 54mm offset. Sorry but I have no clue about 10.5" I would guess subtract an inch?

 

May help (?):

http://www.joby.se/corvette/div/corvette_wheels/

 

Offset is the distance (in mm) of the wheel flange from the centerline of the wheel. A stock late C4 9.5 inch wheel has an offset of 56mm.

If you want to go to a wider wheel and have all the additional width added toward the inside of the car, you just add the 1/2 the additional width to the offset (1 inch=25.4mm). So, a 10.5 wheel would be 56mm + 0.5 x 25.4=68.7mm offset. An 11 would be 56 + .75 x 25.4=75.

I repeat, these offsets add all the width to the inside of the car and will likely cause clearance problems. Using a wider wheel with the same offset as stock splits the difference and adds an equal amount of extra width both inside and outside, which does push the tire out further.

 

If you're interested in a 10.5" wheel I believe you'll find 65mm offsets frequently. A 65mm offset on a 10.5" wheel would push the tire/wheel out board 4mm. That's based upon comparing a 9.5/56mm stock wheel.

The CF actually has a "wheel calculator" that works pretty well. It isn't what I use but I've done the math for a few and it's pretty comparable. I don't use the tire aspect of the CF calculator because it's all based on advertised dimensions and that's not the ideal way to do tire fitments.

https://www.corvetteforum.com/forums...calculator.php

 

Anyone know the offset of the c5z 18x10.5? Ive seen on the net 58mm and 65mm so someone is posting the wrong info.

 

if you don't want your wheels sticking out go with 9.5 i been talking to a sponsor in this site and i was told by him... i was going to go with 10.5 but after i was told it was going to stick out i went with 9.5.... hope that helps your decision

 

You were perhaps misguided by the sponsor in your conversation. Wheel/tire placement is determined by the dimensions of the entire package but is controlled by the "offset choice" - the "offset" you were discussing might NOT have been a desirable choice but it had nothing to do with the 10.5" width wheel.

You need to be somewhat cautious of the "NET" - When shopping or comparing wheels you need to be maybe more cautious. Regarding what you've read? If you're shopping wheels there are "replicas" of nearly every OE wheel done in various width/offsets for many applications.

The OE/GM C5 Z06 rear wheel is a 58mm offset and that's what you should see most frequently. A 65mm could be a "replica" advertised by a wheel manufacturer.

I mentioned a 65mm offset for reference in my post #5 because that specification most closely replicates C4 9.5X56 placement in known available product. Cray does most every wheel they make in an 18/10.5X65 - quality and reasonably priced product I believe.

In your original post you only mentioned "width" and there was no reference to a particular wheel. An original C5 Z06 10.5 X 58mm should stay well within the wheel-house and be an acceptable fit for a later 88+ C4. Mathematically that's an 11mm "outboard push" vs. the OE C4. A "replica"? You need to be very cautious of the offset.

 

I used this site to help me get mine right http://www.rimsntires.com/specspro.jsp I also would say use a quality wheel adapter instead of a spacer. The best explanation of adapters I herd was it's just like bolting on a wheel or hub if done right. I'd at least go with hub centric and if you can hub/wheel centric, but usually when wheels are changed to aftermarket they are no longer centric. Gotta retorq them like you would a wheel cause alum/alloy can creep some.

 

I would love to buy some Fikse fm5 or ccw classics but the price new is just a little extreme for me. They don't turn up used very often. So that being said I've been looking at the weld rts. I'm a dealer so I can get these delivered kinda cheap. I'm also a machinist so I planned to make some billet center caps. When doing so I can make them centric spacers too. Weld offers a 17x10.5 in 52mm and 65mm off set. I really hate the idea of any spacer.

 

Boot77 thanks! That's exactly what I was looking for.

 

Have a question to whom anyone that can accurately answer this: Is the off-set on the factory 17" x 9.5" wheels the same front and back? I'm thinking of going that route on my '96, that has the staggered sizes. This will allow me to use the more readily available 275/40R-17 all around. Thanks in advance.

 

17 X 9.5 OE/GM C4 wheels are all done at 56mm for offsets. A pair that matches your rears would allow you to do the 4 X 275/40R-17

 

Thank you!

 

I have some machined 9.5 rears and a full set of 91?92? Silver with machine lips for sale. Have near new nitto 555 too. Think they are 285's have to look