Will the new corvette zo6 rims fit on my 1985 pontiac trans am do both cars have the same bolt pattern

Hi and welcome to the boards. First, take a moment to read the sticky posts at the top of the forum. These will give you a general run down of the rules as well as answer some common questions. This question belongs in the suspension and chassis forum, so I will move it there. Second, check out the search feature. A lot of questions have been asked before, sometimes several times. Spending a couple moments using the search can get you the answer you are looking for quickly. If you have any questions or comments, PM me. Thanks.

So what's the stock bolt pattern measurement? I cant even find it anywhere and I've been looking through stickies... I just found out how to take a tape measure and measure it... but that's about it...

And to the OP... I thnk the bolt pattern is the same but you're going to need an adapter or spacer or something because the offset/backspace is different.

did some research on the bolt pattern and it turned out pretty good they both are the same 5-475. these wheels should should look good on my 85.

your gonna need a crazy spacer to fit those wheels like over an inch maybe two. but it can be done

i am personally against wheel spacers because they increase load on wheel bearings and studs, you should know about that before you throw down some serious loot on this stuff. its kind of like using a cheater bar to get a stuck nut loose, you're give the wheel a lever to torque on everything its bolted to, oh and involving a peice of aluminum which aint so hot with taking shocks (cracking shearing) into a highload situation. plus the PITA of doing anything that requires the wheels to be off. hope that the spacers you get are made right since if they crack or break you're probably going to see your wheel outrun you down the street. kinda of a risk just to get some nice looking rims

well if u buy shitty spacers you have to worry i had slicks on my 83z with 2 inch skulte adapters and never had a problem with the salad shooters so buy them and put the rims on there

Quality Bolt on spacers are fine, been using them for 6+ years on my cars and no issues at all.
I ran the C5 Z06's (18x10.5 & 18x9.5) on my car for a few weeks, didn't like the rear sticking out the way it did, so I sold them.

transamkid: I am going to install my factory 4th gen wheels onto my 3rd gen '87 IROCZ. I purchased spacers from www.skulte.com.. My 3rd gen car has 0mm offset wheels on the front and 16mm offset wheels on the back. My '99 Camaro SS wheels are 50mm offset all around. 2.0" spacers should work for me. However just in case, a purchased a pair of 1.75" spacers. I will post next week on the results.

hey thanks for the website doc ill be sure to check it out. your car looked good zepher besides the fact they stick out a little. send some pics of your car when you put 4th gen wheels on your 3rd gen id like to see it doc!

oh yeah checked out the website very helpful. THANKS! Zepher you didnt have any troubles with the bolt on spacers because they do kind of look like they would give out after awhile like rockit said. also could you tell me if they can hold up to high speed driving conditions because im 18 and i still want to take on the occasional mustang!!!!!

High speed driving in a straight line doesn't stress the spacers at all.
Andris Skulte takes his car on to road courses and I auto-x my car once a month.
This is one of my auto-x sessions,
http://youtube.com/watch?v=yEb8eRJRctE

Zepher… what offset and what size spacer were you running?

I just grabbed some 18x10.5 rears with 58mm offset, and running a 2” spacer with 295/35/18 tires they look like this (don’t worry about all the bondo dust and assorted body work in progress, I’m actually removing all the old bondo work on the project car and pulling/straightening all the sheet metal, so far everything that I’ve spent any time on is within a 1/16” of an inch of where it should be so there should be little if any mud on the car when I’m done):




It basically looks to fit OK like that, I’ll probably end up with a 1.75” or so spacer just to tuck the tires a little more, but as they stand they clear with completely unmodified inner fenders, rolled outers. The only place that they get really close on the inside is in the front inner wheel well where most big tires get close, and I’m not even sure that I’d have to remove the bump stops like it sits. With the thinner spacers I’ll have to modify the inside, but I need to do that to run 275 width drag radials on the car anyway, so that’s a non issue.

These are actual Z06 sizes and I decided to go with the stock z06 size on the front… 265/40/17 on a 17x9.5 with 54mm offset and a 2” spacer… those should fit and tuck well, I’m more worried about them being a little on the small side rather then sticking out.

The wheels I had were offset to perfectly fit inside a 4th gen Camaro's wheel well. I had an LS1 rear in the back, 295/35/18 Kumho MX tires.

If mine sat like yours, I'd still have them.

Sorry for the late response - I just saw this thread...

I'd just like to clear up a common misconception. The load on the studs, hubs, bearings, and suspension components depends on where the centerline of the tire is. A 0mm offset wheel with nothing and a 50mm offset wheel with 2" billet wheel adapters will put exactly the same load on the hub. Think of it as bolting the adapters to the wheel - that's now a one piece unit (about 20,000 lbs clamping force from M12x1.5 studs torqued to 85 ft-lbs) that has a essentially a zero offset. The rim is now identical to the 0mm wheel.

The adapters will not put any greater load on the studs. The point of studs and lugnuts is to clamp the wheel (or adapter) tightly against the hub. There shouldn't be any "breaker bar" force as long as the lugnuts are still tensioned, since the adapter (or wheel) is square to the hub. Think of studs/lugnuts as a kind of C-clamp. All any extra sideways load will do (such as cornering) is try to stretch the studs, which is straight tension, not bending. Vertical loads could put a bending load on the studs, but it would have to be quite severe to overcome the 20,000 lbs clamping force on every wheel. The adapters are also hubcentric, so the inside diameter of the adapter is the same as the outside diameter of the hub, which prevents any movement as well, and is the same as the OEM wheels. I'm not sure what "cracking shearing" is. Are you referring to the fatigue life of aluminum (Stress vs Cycles, SN Curves - http://en.wikipedia.org/wiki/Fatigue...The_S-N_curve). Steel has an infinite life, as long as the loads don't get too high. Aluminum, on the other hand, has a finite life, based on how many load cycles it's gone through. Since clamping the adapter to the hub (and wheel to the adapter) sandwiches everything together tightly, there isn't any motion, and cornering loads are small compared to the preload from torqued studs. This puts you way on the right side of the SN curve, in the millions of cycles lifetime. There are many aluminum suspension parts in use (including most wheels), which see much higher stresses than adapters, and they're not on a replacement schedule by GM.

That being said - if you bolt a 2" adapter to a 0mm wheel to move the centerline out two more inches, yes, that will put a greater load on the bearings.

Anyways, sorry that my quick response turned into a novel!

Hello Everyone! i am new here and love the site. I have a 1982 Trans Am 305. I was just wondering if any of you think i would need a different setup than what 83 Crossfire TA has on his... i dont figure i would but i am not sure if the wheel well is different or if there will be any different clearance issues as far *** suspension may go. Thanks for the help in advance!

I'm lost, Do I need spacers to fit 84 Vette rims on a 92 RS?

82… the wheel wells, suspension… are all the same size… supposedly, but I’ve had a few people on this board claim that the combination that I posted doesn’t fit. I’ve had an 83, and 2 87’s and have worked on probably most years of third gens and haven’t seen anything that should make that kind of difference, I suspect that those that had problems either had the wrong size spacers or got wheels with a different than original backspacing.

And yes, you’ll need spacers to run the early C4 wheels, but I don’t know what their offset was off the top of my head so I don’t know what will fit. Andris’s site lists “safe” spacer sizes, but I don’t always agree that they are the sizes that I’d want to run for a best fit.

Thank you