I have a 77 c3 and i would like to put my 5 spoke c6 wheels on it. The wheels are 18x8.5 and 19x10. 245 tire in the front and 285 tire in the rear. Just a basic stock c6 setup.

Ive done alot of research on here and everyone says they will work with a 2.5" spacer. However when i jacked the car up i and put the new rim on in the rear, i came up with a 4.5" gap from the fender.

I dont know if they even make a spacer that big and if they do, safety then comes into play.

How are you guys making this work? Im at a loss.

 

I'm not at home to post the links, but BLCKSLVR79 has them and there are various post on the net with him explaining what he used. Off the top of my head they are 3.5" spacers rear and 2.75" front. They are special order by a company in Florida, again don't have the name off hand. $450-500 for the spacers.

..I have a set I am using on my build. I went with different tires for some more sidewall. Stock to me on the C3 just isn't enough - 245/45/18 front and 285/40/19 rear.

 

I'm pretty sure the "supplier in Florida", that 'Ibanez540r' refers to, is Vette Brakes and Products.

 

No, VB&P are not doing them anymore. This is the company that guys are going with. Both wheel and hub centric

http://www.motorsport-tech.com/

 

...aaaannnnd they're out of Nevada, not Florida - my bad

 

I just dont see how 3.5" will be enough i measured 4.5".

 

In all honesty, do you really want to run a spacer that thick, on a spindle that wasn't designed for it?

 

No...but I've seen alot of guys on here make it work somehow I want to know the secret lol

 

They use adaptors not spacers. I have 2 1/2in on mine
with c5 wheels for years, not one problem.
Engine is a built 406 and 150hp shot of nos. Ran 11.5 in the 1/4 mile

 

What you need are bolt on adapters to make up the difference in backspacing from the stock wheels to the C6 wheels. Your stock 8" wheels have 4" backspace. Since you want to increase the wheel widths in both front and rear, this needs to be taken into consideration as well.

Your new front wheel is 8.5", using a net backspace of 4.5" would put the outer face of the wheel in the same location as the stock wheel.

C6 front wheel: 18x8.5, 56mm offset, 6.95" backspace. Subtract 4.5 from 6.95 and you get 2.45", which you're unlikely to find in an adapter, so use 2.5". This will push the front wheels out by just a little bit from the stock location.

Many guys that run 10" rear wheels under the stock body report that 5.5" of backspacing works successfully.

C6 rear wheel: 19x10, 79mm offset, 8.61" backspace. Subtract 5.5 from 8.61 = 3.11". Again, you'll not find an adapter off the shelf at 3.11", so you could use either 3", 3.25", or 3.5". With a 3" adapter you'll net more than the 5.5" backspace I mentioned above, which may or may not cause interference issues on the inboard side. 3.25" would be safer from a clearance standpoint, but will push the wheels outboard a bit.

Be aware that all cars are different, and you need to watch for interference (especially in the rear) with frame rail, sway bar, and e-brake cable bracket. I use 17x11" wheels with 4.5" backspace in the front, and get a light rub on the sway bar at full lock.

Hope this helps.

 

I'm FULLY aware of what they are. They still impose loads on the spindles that they weren't designed for....

 

Thanks for the in depth response. Any idea where I can get these and how much?

 

http://www.motorsport-tech.com/boltpatternguide.html

 

Can you explain this further? The way I see it, if you use wheel adapters to put a different offset wheel in the same relation as the stock wheel, where is the extra stress? The wheel is still centered. If you were to put on an adapter and then put the stock wheel back on, there would be added stress because the centerline of the wheel would be moved outward.

 

I have had these on all year. Drove the car 4,000 miles this year. Took my car on Hot Rod Power Tour which started in Texas and I live in Chicago. Car rides so much better then the BF Goodrich Radial T/A's I had on it.

I put Michelin Pilot Sport 275/40/18 rear 265/40/18 front with 2"spacers on rear and 2.5 spacers in front.











Hope this helps

 

They look just like mine. I have 285 in the back and no problems

 

The way it was explained to me, is the wheel imparts it's loading to the spindle through the center pad of the wheel, and in this case, you're talking about moving that contact point 2.5" further out on the spindle. The spacer is giving the wheel additional leverage against the hub and spindle.

 

I disagree. How does the spindle know whether there is a 8" wheel with 4" backspace, or a 8" wheel with 6 1/2" backspace plus a 2 1/2" adapter? Both scenarios end up with the wheel centered the same.