Wheel swap
 

I currently run a C4 on road race track. I run a 4x setup Hoosier 315R35/17 on a ZR1 C4 wheels (17x11). I have no clearance issues.

I now have a another racecar C5 2001 that will run OEM C5 ZO6 wheels (18x10.5) with 315R30/18 Falken.

To avoid buying more tires for the C4 I want to use by C5 wheel and tires.

my question is. Can I put the C5 wheel set up on my C4 by just bolt on and off?
if not what space would I need and for which location? Source of spacers?

thanks in advance the help.

I am assuming your ZR1 wheels are 36mm offset? (Factory GM) and you are running them on an 84-87 car?

I didn't think the ZR1 wheels bolted up to the 88+ cars without wheel adapters. More info will help.

If they are in fact ZR1 wheels and your C4 is 84-87, you will need to use a 25mm spacer. The 84-87 cars had 32-38mm offset and that is why the ZR1s bolt right up. 88+ used 50(?)mm ish offsets

You should be good.

Since you own both race cars, how about just swapping them and checking clearance on the driveway?

Update My car is 95. I currently don't use spacers. ZR1 wheels are factory OEM with 36 offset. My question still remains. Will the ZO6 2001 wheels bolt on to my C4? I'm tight in the wheel well now with 315R35/17 and the new tire will be 315R30/18 so same width and diameter. The zo6 have a 58 offset. Does that mean I need a spacer? Front or rear? Or since off set larger on Zo6 will it just stick out further.

The distance in offset is distance from the center line of the rim. A higher positive offset means the part of the rim that sits flush against the rotor is further away from the center of the rim. Positive offset is towards the face of the rim, negative is towards the rotor. Do your +36 wheels stick out far? I thought wheels up to 2004 just bolted up to the 88+ cars

https://tiresize.com/wheel-offset-calculator/

This is one of the best calculators i've used. It compares 2 different wheels and shows you if they will sit more inboard or outboard

This is a great tool and what I was looking for!!! thank you. Based on info, I would need to have 7/8 spacer to put it in the same location. I do have longer AP Studs so I should be ok. Unless that spacer is to large?

I think you're looking at this backward. The C5 requires far more positive offset than an early or C4 ZR1, whereas wheels spacers (or adapters) reduce effective offset. IOW, on a C5 that wants around 54mm offset for an 11" wheel, your ZR1 wheels with 36mm offset will stick out of the fenders. You can't fix that with spacers. They should be doing the same on your 95 unless you have flares, btw. An 88-96 C4 will take similar offsets as a C5 Z06.

I definitely would not put a 7/8" spacer on a race car. You'll snap your studs on the first corner.

I no flaires. stock body. ZR1 put the tire outside of body about 1/4" which is ok. I have two race cars and don't want to buy all these wheels. with the new C5 car I must run a spec series wheel and tire. So I'm trying to be frugle and use the same C5 set up on the C4 if possible. I do know the C4 is already very close to sway bar and wheel housing and can't get "closer" inward.

Oh, okay. You can use C5 wheels on a C4 generally. Some may have a smidgen more offset than for a C4, but small spacers can manage that. At the very most, we'd be talking about 1/4". As long as you have adequate threads on the studs, it will work fine.

[QUOTE=billschroeder5842;1598074756]You should be good.

Since you own both race cars, how about just swapping them and checking clearance on the driveway?[/QUOTE

I havent bought the new wheel yet.

I would say they will bolt up and be fine without spacers/adapters. The ZR1 Wheels stick out past the fender, the new wheels probably won't because of the different offset. They should sit more inboard.

I have a 91 so it is basically the same as your 95 as far a suspension goes. I have tried swapping over some Z06 wheels from my brother's 04. The rear fit fine with no issues. The front would hit the sway bar and i would have to run a small 1/4-3/8 spacer to clear it (my car already has longer studs so it won't be an issue). Once i run out of tires on my 16 and 17" rims, i will be switching to 18x10.5 all the way around. It can be done with little issues. If you get more than 1/2" spacers, it is advisable to run adapters instead. The adapters bolt onto the current hub and then have new lug studs to bolt the wheel to.

Every car is different so a test fit wold tell you the most about what you would need.

Here are a couple of pics i took of the front with an aftermarket 18x10.5 wheel ($150 on ebay) with a 275/70/18 tire on it. The wheel was going to contact the sway bar when it was at full lock. The OEM Z06 wheels were a bit better than the aftermarket, but i still felt they would need a small spacer.


https://cimg3.ibsrv.net/gimg/www.cor...428a30dc50.jpg
https://cimg5.ibsrv.net/gimg/www.cor...9fb052030a.jpg

Something is odd here. The front C5Z wheel is 17x9.5 with offset of 54mm, which gives backspacing of only 7.38". That's almost identical to a stock C4 17x9.5 that has offset of 56mm. They should fit just fine. The rear C5Z is 18x10.5 with 58mm offset, and will have 8.03" of backspacing. That's about the max backspacing that will fit on a later C4, but it should fit on all four corners. Note that I have three sets of wheels with similar backspacing and they fit just fine. Certainly though, running 1/4" spacers would not be a problem if needed.

I have a 91 and I run 10.5" c5z wheels at all 4 corners at the track, no spacers. Iirc the front tire would barely rub at full lock, not anything to worry about during normal driving /racing. I have steering limiters to keep from destroying my brake cooling ducts so it's a non issue for me. Mine are factory Alcoa but I think they all have the same offset.

Thanks. I ordered a set and will try

Thurman_merman What is your tire size? 315?

[QUOTE=emarkovits;1598087069]i think he is trying to say: you have the other car right? (C5)
take it's wheels off, and put them on the C4 to check the fitment...
right? :rolleyes: