So I've tried searching some past threads and can't really find my answer. I have a 1977 C3 and I am currently looking to replace the wheels. I found some Jegs wheels I like but curious on the offset/backspace. I'm running stock suspension with a 245 in the front and 275 in the rear.

I decided to go with the Jegs SSR Star wheels. I'd like to go staggered. So looking to do a 15x7 front and 15x8 rear.

The 15x7 specs are 5x4.75 bolt pattern, 0mm offset and 4" backspace.
The 15x8 specs are 5x4.75 bolt pattern, 0mm offset and 4.5" backspace. They also come with a 27mm offest and 5.5" backspace.


Will these work on my vehicle and which rear should I go with??

 

Your stock wheels are 15x8, 4" backspace (and were optionally fitted with 255/60r15s in later years). The 15x8s, 4.5" backspace should work front and rear, but will look/fit a bit better with a spacer to bring them back closer to a 4" backspace (they'll sit inside the guards a bit). I'd run a wider than 8" wheel if wanting to run a 275 wide tyre too, personally. The 275 can be fitted to the 8" wheel, but will be a bit floppy/floaty.

Edit: Haven't seen those wheels before, I quite like them though, similar to Weld stars. Should look good!

 

Thanks, yea I like them! So the 15x10s I'd have to run adapters? Was kind of wanting to go staggered with the 15x7 or 8 up front and wider in the rear. The 15x7 had 4" backspace so I wouldn't need a spacer up there if I went with them right? Anything wide backspace in the rear will need a spacer to look right?

 

Ahh, you edited it. In terms of looks and fitting a wider tyre the 15x10s would be ideal for the rear, but would require offset trailing arms and I expect a shorter/shortened spring and modified or removed rear sway bay if you have one. Would look great though, and fit the 275 nicely.

 

We're posting at the same time! Oh well. Spacing the 15x10s in the rear will put them outside the fender I expect. I don't think you could run less than an effective 5" backspace with the 10"s and still have them sit within the guards (but then maybe you're looking for the tall rear with tyre sticking out look?), and I don't think you'll be able to run 5" backspace on 15" wheels without offset trailing arms at least. In this thread on the tech forum: https://www.corvetteforum.com/forums...heel-size.html I posted some pics of the mods I made to fit 5" backspace 17" wheels on my car, and to show some of the clearance issues with the trailing arms for different wheels.

 

Ok so scratch the 15x10s...so if I got with the 15x8s with 4.5" backspace all the way around I would need atleast a .5" spacer all the way around? What about the 15x7s with 4" backspace.

 

I'm running 4.5 inches of BS on 17s and am about 1/2 inch from the E-brake cable as well as the leaf spring. I'm additionally running a 3/16 inch spacer to clear the brake caliper. The wheels you are looking at will probably need a small spacer to clear the caliper to start with. A 15 inch wheel with 5.0 to 5.5 inches of B.S. is going to put you in contact with the cable and leaf spring (as MH pointed out would require offset TAs). A 15 X 10 with a 275 and 4 inches of backspace will work (will probably just put the wheel lip past the fender lip). A 275 on a 8 inch wheel (with 4 inches of BS) will bulge the side walls to much (as MH again pointed out) but will put the tire right at the fender. A 275 tire is right at 10.5 inches wide. A 15 x 10 wheel is actually 11 inches wide. So you really want a 9.5 inch wide wheel (which is actually 10.5 inches) to exactly match the width of the 275 tire (to have no ballooning or bulging of the side wall with like an 8 inch wheel). I have 275s mounted on an 8 inch wheel and can post pics if you would like to see (the ballooning sidewall). And to complicate the whole situation, no two cars are exactly the same.

 

17 x 11 wheel is actually almost 12 inches wide.



4.5 inches of BS on a 17 x 11 wheel - with a 3/16 inch spacer to clear the caliper.

 

275 on a 15 x 8 with 4 inches of BS. Side wall is ballooned out a bit. Slightly wider wheel (say 15 x 9 or 9.5 with 4 inches of BS) would even the wheel lip with the tire width which would be right at the fender lip.

 

Ok, so the wheels I am looking at are 15x8 4.5 backspace. So I would have to run a spacer correct?? And if so what size do you recommend? Half inch? Any good spacers recommended?

 

Food for thought: For the rear, as the wheel diameter increases, so can the BS without the need to modify the trailing arms. Then you would save the cost of spacers and tuck a wider tire into the wheel well.

 

17" wheels will conflict with emergency cable bracket,
wheels larger will clear the bracket.
if your buying new wheels, plan for correct offset without spacers, spacers are bad,
you loose hub concentric, wheel adapters are available with Hub concentric.
I would not run spacers or adapters, without Hub concentric, (they keep the wheel centered around the hub.)
spacers Do Not.

 

I initially planned for 18s but recently had a blow out and was stranded by a nearby tire shop. Ended up buying all new tires to fit the 15s I have now. So figured I'd just find a 15 that I like and go with that.

I agree on the hubcentric spacers. Looks like the smallest they make is 1". Will that be too much spacer for the 4.5" backspace?

 

If at all possible. Go with 4 inches of backspace. That's the factory BS. Especially if going with 15 inch wheels. The problem with a 1 inch spacer is that you will probably have to replace the lug bolts with longer ones. I would stay away from a spacer. Did you put a 275 on the back when you bought new tires?? If it were me, I would run a 15 x 9 with 4 inches of BS In the back. Then the tire will not have such a balloon appearance versus being in on a 8 inch wheel. Factory 4 inch BS will additionally eliminate any issues with hitting e-brake or leaf spring. Again, that wheel will probably need a 3/16 inch spacer to clear the brake caliper. Does that wheel come in 15 x 9?

 

Maybe I'm using the wrong term. Instead of spacer I was looking at hubcentric adapter. The car had 275s on the rear from the get go so just replaced with the same size.

 

Just for your reference I have 15x10 wheels with 3.5" backspacing. Having a 15x10 with 4.5" backspacing would still stick out I would think. However, I do not have any spacers or adapters.

 

Kubs- That is more or less the look I am planning for - kinda "old school" with fats in the back and thinner in the front with a bit of the fat sticking out in the back, and the back raised a bit to lower the front and have that aggressive look from the late 70's. What size tires do you have on the rear in the pics? Thanks for the pics and info - writing it down for future reference. Not sure how skinny up front I want to go, but that is the idea! Maybe do 15x7 rims? Good tire size for adequate handling yet cool looks?

 

Mine are 15x10 and 265/50R15 tires all around. The fender gap looks huge because I went from a 27" tall tire to a 25.5" tall tire. I plan to lower mine so there is only about 1" of rake.

 

Correct. As 69Vett stated, make sure they are hub centric adapters or spacers. The adapters bolt on and then the wheel bolts onto the adapter. The spacer just slides in place and is held there by the actual wheel. I know we were thinking the same though. My spacers are 3/16 and hubcentric. Another thing to consider is those wheels you are looking at are probably not hubcentric (compared to the stock corvette wheels and rotors. Here are the 2 inch adapters I mocked up my rear with. the stock corvette wheels fit snug on the lip of the adapter.



My billet specialties are not hubcentric. I plan on getting rid of the 3/16 spacer when I buy aftermarket calipers which are a little thinner. Again, I'm betting the wheels you are looking at will make contact with the calipers - requiring a small spacer.





Reading your reply to Kubs, I see you plan on having a little tire out past the fender. In that case, you want less B.S. - say 3.5 inches (as Kubs has). I'm about an hour from you. I have a spare wheel 17 x 9.5 that has 4.5 inches of back space with a 275 tire on it if you want to mount it and look at it before buying anything. Just let me know. I researched for weeks before buying and still needed a spacer that I did not anticipate. I even told the guy wheels were going on a corvette. This stuff is trial and error unfortunately.

 

I wasn't the one to reply to Kubs that was someone else. So let me ask you this. On the 17x9.5 with 4.5 BS would be different then the 15x8 with the 4.5 BS since it's 1.5" wider right? So I could just judge it based off that it will be not as far out basically 1.5"?

Im curious if I need to do a small spacer like your are running or if a 1" hubcentric adapter would be too wide.