C3, 68 coupe wheel hell

[Ed Driscoll]

I've purchased the wrong wheels. ouch. I was told that the correct wheel was 15 X 7 and it had a 4.25 in backset. the front caliper hits the wheel well before it mates to the rotor. Does anyone have the correct wheel information? I was lucky enough to sell the wheels and tires on the spot for what I paid for them. it turns out they fit nicely on a camaro with small calipers.
Thanx
vin 194378S412918
327/300
no options that I can see, so I'm assuming (gulp) no HD brake package (if one exists at all)
Thanx
Ed
#38868
ps
the original wheels are long gone, and the keystones that were on it have spacers.
pss
the new wheels that I purchased had something called an offset, which was noted as 6mm, what exactly is the offset?

[Joe L.]

Re: C3, 68 coupe wheel hell

Ed-----

The term "offset" refers to the displacement of the wheels mounting plane (center section) from the centerline of the rim section. If the mounting plane is displaced outboard of the center of the rim section, then the wheel is said to have positive offset; if it's inboard of the centerline, then the wheel has negative offset.

The term "backspacing" refers to the distance from the rear edge of the rim section to the mounting plane of the center section. This measurement is always a "positive" number.

For 1968 Corvettes you need an a 15 X 7 wheel coded "AG" near the valve stem hole. This wheel has an offset of -0.28. Stated in terms of backspacing, this wheel would have a 3.22" backspacing. Camaro 15 X 7 wheels have an offset of 0.30 or, stated in other terms, backspacing of 3.80".

Fuctionally, you could also use the 15 X 8 69-82 Corvette "AZ" wheels unless you are after exact correct originality.

[Ed Driscoll]

Re: C3, 68 coupe wheel hell

Joe,
As always, thank you for the info. I've found a set of 15X8, coded AZ at the valve stem. Do you know if there was an HD brake package in 68? Just making sure I don't have a larger caliper then the wheels will support in terms of clearance.
Thanx

Ed

[Craig S.]

Re: C3, 68 coupe wheel hell

Ed - any of the HD brakes in this era were the same calipers with dual pins versus teh single pin, and it would be very doubtful you have these anyway, but even if you did, there is no dimensional difference in the calipers, they were the same castings. So, you will have no issues with your wheels....Craig

[Ed Driscoll]

Re: C3, 68 coupe wheel hell

Thanx Craig,
I found the correct wheels as well, now I'm just debating the price/importance ratio.
Cheers
Ed

[Joe L.]

Re: C3, 68 coupe wheel hell

Ed-----

Yes, as Craig mentions you have no concerns regarding brakes and wheel fitment. From a wheel fitment perspective, all Corvette calipers used from 65-82 were the same. So, even if the calipers on your car have been exchanged and the units now on the car were originally from a different year, it will make absolutely no difference, whatsover, as far as wheel fitment is concerned.

You can obtain brand new, replacement wheels of the original size and configuration from Wheel Vintiques (www.wheelvintiques.com). These folks have the Corvette 15 X 7 wheels available in several "backspacings". Using their measurement system, you will require those with backspacing of 3-3/4". This will provide a wheel with dimensional specifications virtually identical to the original wheels used on your 68.

I don't know if these wheels will be identical in all of the fine nuances of configuration such as stamped "numbers", manufacturer markings, or "wheel codes". These wheels sell for about 70 bucks each.

[Ed Driscoll]

Re: C3, 68 coupe wheel hell

Thanx Joe,
I found a set of 15x8, with the code "AZ" next to the valve stem. I know they're not the original 15x7's that the car came with, but they come with all the caps and rings and the guy is very resonable in terms of price, so, as I understand it from the previous post, these should do OK. I'm looking forward to driving.
Thanx again,
Ed

[Craig S.]

Re: C3, 68 coupe wheel hell

Ed - as Joe mentions, they will work fine, and, as a bonus, you can mount slightly larger tires, still well within the fender clearance limits of your car. Enjoy!....Craig

[Ed Driscoll]

NM; Thanx for all the help *NM*