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Old 01-26-2017, 11:42 PM
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1993C4LT1
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Default Wheel offset question

Been looking to complete this set. Came across a 17x9.5 with a 5x120 bolt pattern, but with a 43mm offset. My car is a 93, so how bad will it look considering 88-96 C4 are 56mm offset?


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Old 01-27-2017, 03:39 AM
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5 X 120 isn't correct either so .................

What are the 3 wheels you're attempting to match? Brand, model/style and the casting information from the wheel back-side is required!
Old 01-27-2017, 05:19 AM
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Back spacing and offset always get me confused but looks like you might need a 13 MM spacer or something close. Years ago I had some hub centric 14MM spacers made so I get the GrandSport wheels on the back of my Z,a little pricey but they did the trick. Had to use longer wheel studs but didn't have any issues with the spacers. One positive thing about the spacers is you can have the wheel sit where you want it in relation to the wheel well.
Old 01-27-2017, 06:33 AM
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I admit I'm no backspace guru, but I don't think a +43mm rim is going to work, let alone the different bolt pattern. Your bolt pattern is 5x4.75 which is something like 5x120.64 or there abouts. I've seen that bolt pattern listed (5x120) but it's for an import which means the bolt pattern is narrower than on your car.

As I understand it, the backspace is the distance from the centerline of the rim to where the hub mounts. So a smaller number would push the rim out further in this case. Adding a spacer will push the rim out even further.

IMO you want to find a rim with the correct bolt pattern and offset assuming you want them to match in layout.

Regarding the ZR1's, didn't they come with a +36mm offset on them like the older C4's? That was why ZR1 rims work on older C4's without adapters. You want rims with 56mm offset, regardless of the year they came off of.

Sorry, don't think the one mentioned will work in your case, assuming what I believe is correct actually is correct.

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Old 01-27-2017, 08:10 AM
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Originally Posted by WVZR-1
5 X 120 isn't correct either so .................

What are the 3 wheels you're attempting to match? Brand, model/style and the casting information from the wheel back-side is required!
Those 3 wheels are Fikse FM5's. So no info behind them. Weird, always thought vettes were 5x120. I test fit those on my car, and they fit great.
Old 01-27-2017, 08:12 AM
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Originally Posted by Z51JEFF
Back spacing and offset always get me confused but looks like you might need a 13 MM spacer or something close. Years ago I had some hub centric 14MM spacers made so I get the GrandSport wheels on the back of my Z,a little pricey but they did the trick. Had to use longer wheel studs but didn't have any issues with the spacers. One positive thing about the spacers is you can have the wheel sit where you want it in relation to the wheel well.
Thanks Jeff! I know the ZR-1's have 36mm offset on the rear. And when people out those on base C4's, they stick out. Making me think the 43mm will stick out a bit also.
Old 01-27-2017, 08:14 AM
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56mm offset is about 2.21" from center. 43mm offset is about 1.70" from center. So you would be looking at the wheel itself would stick out a little over a half inch farther than the stock wheel. Then you have to account for the tire and is it wider than the wheel.
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Old 01-27-2017, 08:17 AM
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Originally Posted by hcbph
I admit I'm no backspace guru, but I don't think a +43mm rim is going to work, let alone the different bolt pattern. Your bolt pattern is 5x4.75 which is something like 5x120.64 or there abouts. I've seen that bolt pattern listed (5x120) but it's for an import which means the bolt pattern is narrower than on your car.

As I understand it, the backspace is the distance from the centerline of the rim to where the hub mounts. So a smaller number would push the rim out further in this case. Adding a spacer will push the rim out even further.

IMO you want to find a rim with the correct bolt pattern and offset assuming you want them to match in layout.

Regarding the ZR1's, didn't they come with a +36mm offset on them like the older C4's? That was why ZR1 rims work on older C4's without adapters. You want rims with 56mm offset, regardless of the year they came off of.

Sorry, don't think the one mentioned will work in your case, assuming what I believe is correct actually is correct.
Yes you are right. 13mm is about half an inch, so that's how much it'll get lushed towards the hood, because it's going on the front. Yup, older c4's and zr-1 rears are 36mm offset. I believe the GS rear is 50. Thanks again guys. Looks like I'll have to pass on it
Old 01-27-2017, 08:27 AM
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Originally Posted by 1993C4LT1
Those 3 wheels are Fikse FM5's. So no info behind them. Weird, always thought vettes were 5x120. I test fit those on my car, and they fit great.
Is the "ODD" wheel where you can put your "hands on" or is it a GAMBLE?

You don't know the offset on the three that you have so you can't actually determine what you need. Everything mentioned is "assuming" that the Fikse wheel is a duplication of the factory and that "ain't necessarily so".

Are the tires still on your wheels? If there's nothing on the wheel back-side you're assuming also!!

If you're wanting to "match" you first need to know what you've got. At present I'm guessing that you've only got what you were told by the seller. Is that correct?
Old 01-27-2017, 08:57 AM
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Maybe put a WTB out there and see is someone has one they want to sell in the right dimensions. Who knows, there's probably a wrecked car that had what you want on it that's being parted out.
Old 01-27-2017, 09:29 AM
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Originally Posted by WVZR-1
Is the "ODD" wheel where you can put your "hands on" or is it a GAMBLE?

You don't know the offset on the three that you have so you can't actually determine what you need. Everything mentioned is "assuming" that the Fikse wheel is a duplication of the factory and that "ain't necessarily so".

Are the tires still on your wheels? If there's nothing on the wheel back-side you're assuming also!!

If you're wanting to "match" you first need to know what you've got. At present I'm guessing that you've only got what you were told by the seller. Is that correct?
Yup, just what seller told me. I did measure the offsets way back when and they came out 52mm, but I measured them fast. The odd wheel is not local, so i can't put my hands on it. I'll be honest, if it's cheap enough, I'll buy it
Old 01-27-2017, 09:53 AM
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Originally Posted by 1993C4LT1
Yup, just what seller told me. I did measure the offsets way back when and they came out 52mm, but I measured them fast. The odd wheel is not local, so i can't put my hands on it. I'll be honest, if it's cheap enough, I'll buy it
Well what I'd do is remove the tire from one wheel and do the measuring to confirm what it is that you've actually got. You would measure "total wheel width" (edge to edge) then subtract 1" to get approximate "advertised rim width" - you then measure the back-spacing and using various calculators determine what it is that you actually have. When using the calculators you use the "advertised rim width".

The other thing you need to be concerned with the wheel that's advertised as 5 X 120 is the dimension of the wheel bore. You need minimum of 70.3 and if it's less than that it's a NO FIT!!

5 X 120 is for sure a "force fit"!!

***If you do plan on the "gamble" you need to be able to buy a "wheel center-bore" adapter from what ever the wheel is (if greater than 70.3) to 70.3 or you'll never get the "force fit" to mount correctly to the hub/rotor. You'll most certainly have a drivability/issue. Adapters are sometimes referred to as Centric Rings.

You could certainly end up with this result!! I always maybe enjoyed these guy's dramatics!

http://us.hubcentric-rings.com/why_h.../?src=intpopup

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Old 01-27-2017, 11:37 AM
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Thanks for the help everyone. Doesn't want to sell one to me. Oh well
Old 01-27-2017, 11:38 AM
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I thought he'd sell one, that's why I asked you guys for opinions. He does have 5, which is why I asked him
Old 01-27-2017, 05:15 PM
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Originally Posted by hcbph

Regarding the ZR1's, didn't they come with a +36mm offset on them like the older C4's? That was why ZR1 rims work on older C4's without adapters. You want rims with 56mm offset, regardless of the year they came off of.
I think the GS wheel is 36MM,with the 14MM spacers it brought my GS wheel out to the ZR-1 spec 50MM.

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