Can someone verify my wheel calculations?
 

I need tires for my 85 Corvette this summer, the ones I have are dry rotted and I'm not comfortable going around the corner with them. I have a line on a set of 2002 Camaro SS 17x9 35th Anniversary wheels and tires. I have the Z51 option in my 85 so the offset is +38mm and I'm fairly certain the Camaro offset is +50mm. The bolt pattern is the same but I'll need spacers, correct? I'll have to use 12mm spacers to get me where I need to be if I remember correctly. Any suggestions or advice?

Plug your numbers into this and see what you get: https://www.wheel-size.com/calc/?whe...cl=50mm&sr=0mm

Personally I won't use spacers, too much potential for problems IMO.

Thanks! Cool tool. I may be able to get away without using spacers, I'll have to see how close the calipers come to the wheel.

They will fit but as stated you may need spacers. I have spacer's on both of my 85's, a base and a Z51. Haven't had any problems and the base has seen drag and track time. YMMV.

You have it correct: you'll want spacers of 12mm (1/2" is close and I'm sure it's easier to find) to get those wheels at the location where the factory would have put them. Spacers act to subtract offset from a wheel, which is what you're needing to do. There is no problem running spacers, as long as you have enough threads still showing on the wheel stud to fully engage the lug nut. They are completely safe when used in this manner. If you don't have enough thread, then you can add aftermarket long wheels studs (like those from ARP).

I actually have spacers that have their own studs and use the existing studs to hold them on. They are much thicker that what I need but they were what came on both cars. They work and don't look odd so I didn't change them. I would say to make sure you get hubcentric no matter which type you choose.

I was actually looking at a few sets and I didn't see any in 12mm or 1/2" with studs. I'll have to pull the wheel and see how much thread is there.

Better off to buy the right wheels or fitment that is. lots of stock or aftermarket available with tires. What wheels are on it now?

been using “adapters” (spacers that bolt to the studs and havenew studs for the wheel) from PE Motorwerks on that auction site for 5 years to make c6 base rims fit on my 85, 86, & 87 and no issues.

people use them all the time. lots of possible solutions for you.

Sorry for the confusion. Those would not necessarily have studs. Those would fit over the studs you already have. Though you may, as MatthewMiller stated, have to install longer studs to use just the spacers. HTH.

Right now the car is wearing the stock 16" size tires on ARE wheels, 8" in front and 9" in the rear. The wheels are pitted and need to be refinished and that's not cost effective, I was quoted $100 a wheel. I plasti-dipped them in black for the time being and while it does look good, I still need tires as they are starting to dry rot. It makes no sense keeping the stock 16" as there is only one brand of tire in the stock size so I thought I'd go 17" to open up my options. I liked the look of the 35th Anniversary Camaro wheel, it's a Corvette style wheel but finished in a different way to stand out.

I don't believe you will find a wheel with the proper offset to eliminate using spacers. I couldn't . Here's a link to a thread I started all about wheels and spacers.

https://www.corvetteforum.com/forums...9-5-tires.html

There's way to much BS going on in this thread. You mention having a 'line on' a set of wheels and then you speculate on what you 'THINK' is the offset! You mention comparisons to the original offsets and then mention that your current wheels are 2 X 8 and 2 X 9. The first thing you do is put your hands on the wheels that you've interest in and confirm the 'offset' I'd wager it's cast on the wheel back-side. You don't do a damn thing until you know what you've maybe got to consider.

This thread is a few days old with many comments that very likely ain't relevant. You've only a WAG as to the wheels that you've interest in!!!

If the wheels are actually 9" & 50mm they may actually be a 'better' fit than what you've got currently. and likely an appearance upgrade.

You need to put your hands on the wheels and if maybe they're 'local' maybe do a 'trial fit'

*** I believe you're correct in your assumption but I believe that even Cray if you're shopping for an early C4 considers 9" @ 50mm a fit.
*** If you're interested in an 'actual' comparison pull one of your 8" and 9" ARE and compare whatever they are to whatever the '02 F-body wheels are.
*** The 9.5 @ 38mm aren't actually relevant trying to compare current to the desired!!

I have the wheels, bought them Friday. I actually got 5 of them, newly powder coated silver too, for $150 ($30 each). All are GM wheels, 17x9 with 50mm offset (stamped on the back). The seller had them on a Gen 4 Trans Am with no spacers or adapters. I'm going to pull the wheels off this weekend and mount the new ones to check for clearances and tire position. I don't think I'll need spaces or adapters. Stay tuned.

Those will fit just fine.

:thumbs: Great deal! Especially with a new powder coating.

I never tried the Camaro SS wheels on my '85, but on the later ones they fit perfect. I have the earlier 5 spoke Camaro SS wheels on my '96 right now (with all four 275/40/17 tires). They look like stock on my CE. I like the later Camaro SS wheels also, but I haven't found any at that good of a price.