OEM Z06 Wheel "Offset" Questions

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Oct 2, 2005 | 10:34 AM

Toque

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From: Wylie TX --> Less is More, except under the hood !

OEM Z06 Wheel "Offset" Questions

Guys:

I was wondering if you had the factory OEM Z06 wheels offsets for the from 17" and rear 18".

I did a search and could not find this.

Also... How are these numbers read ?

This might sound strange, but I'm considering taking a factory rear 10.5" Z06 wheel and having it cut to 9.5". That way I have 18" wheels all the way around, and still maintain the light Z06 wheel. I was never fond of the larger sidewall of the front tire compared to the rear.

Thanks !
Toque

Oct 2, 2005 | 11:31 AM

SGT. PYLE

Burning Brakes

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From: Oceanside CA

Front-54mm 7.2 Backspace
Rear- 58mm 7.9 Backspace

Oct 2, 2005 | 04:47 PM

Wah

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From: Columbus OH

I run all 18s with 18x10.5s up front.

If you really did the width reduction successfully, let me know. I'm genuinely interested in finding out how to weld back cast aluminum wheel. Also, I believe you will have to cut out a portion of the outer "barrel" in order to preserve the offset.

Last edited by Wah; Oct 2, 2005 at 04:51 PM.

Oct 2, 2005 | 06:00 PM

Toque

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From: Wylie TX --> Less is More, except under the hood !

Quote:

Originally Posted by SGT. PYLE

Front-54mm 7.2 Backspace
Rear- 58mm 7.9 Backspace

SGT. PYLE

Thanks !

If I'm doing my math correctly (Trying to understand how this works).

Front = 54mm which is 2.1 inches.
Rear = 58mm which is 2.3 inches.

Front backspace is 7.2 inches.
Rear backspace is 7.9 inches.

Added together:
Front 9.3 inches.
Rear 10.2 inches.

Add thoes together and I'm not getting 9.5 front and 10.5 rear. Where am I going wrong here ?

I guess these would br Positive Offset wheels right?
http://wheeltool.com/info/offset.html

Toque

Last edited by Toque; Oct 2, 2005 at 06:16 PM.

Oct 2, 2005 | 06:01 PM

Toque

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From: Wylie TX --> Less is More, except under the hood !

Quote:

Originally Posted by Wah

Wah

Are you running the 295/35/18 up front too ?

How does that handel like that ? Steering feel strange ?

Any rubbing ?

When I had my Z06 wheels repainted this spring I heard the guy at the wheel repair show tell another customer that they performed lots of services... the one that stuck in my head was the wheel re-sizing. I have no idea if they could cut it to 9.5 inches.... This is just a thought in my head for now.... It would be cool to have a genuine 18"x9.5 speedline wheel though !

Toque

Last edited by Toque; Oct 2, 2005 at 06:21 PM.

Oct 2, 2005 | 10:27 PM

b_pappy

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From: the GOCC are everywhere, even back from "band camp"

Offset is measured from the centerline of the wheel to the mounting pad. Back spacing is measured from the back side of the weight flange to the mounting pad. Dimensions of the weight flange will vary with wheel design. What you are talking about doing sounds like a whole bunch of work. I would look for other ways to get your 18's all around.
Bruce

Oct 3, 2005 | 10:49 AM

Wah

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From: Columbus OH

Quote:

Originally Posted by Toque

Wah

Are you running the 295/35/18 up front too ?

No, I run 315/30/18 up front.

Quote:

How does that handel like that ? Steering feel strange ?

Any rubbing ?

Handles much better. Most of the understeer is gone. Steering feels the same. Tiny rubbing at full turns, not enough for a concern.

Quote:

When I had my Z06 wheels repainted this spring I heard the guy at the wheel repair show tell another customer that they performed lots of services... the one that stuck in my head was the wheel re-sizing. I have no idea if they could cut it to 9.5 inches.... This is just a thought in my head for now.... It would be cool to have a genuine 18"x9.5 speedline wheel though !

Toque

Why would you want 9.5" wide wheels while 10.5" will work ? If you want to keep the understeer trait, you can always put narrower tires up front. 295/30/18 will still work just fine with 10.5" and then you can use 315/30/18 in the rear.

BTW, your calculations are incorrect. Wheel width is not a product of offset and backspace.

Oct 3, 2005 | 11:15 AM

Toque

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From: Wylie TX --> Less is More, except under the hood !

Quote:

Originally Posted by Wah

No, I run 315/30/18 up front.

Handles much better. Most of the understeer is gone. Steering feels the same. Tiny rubbing at full turns, not enough for a concern.

Why would you want 9.5" wide wheels while 10.5" will work ? If you want to keep the understeer trait, you can always put narrower tires up front. 295/30/18 will still work just fine with 10.5" and then you can use 315/30/18 in the rear.

BTW, your calculations are incorrect. Wheel width is not a product of offset and backspace.

Wah:

Thank you very much for your explanation. I am still learning about wheel offsets etc.. I thought you added the backspace and offset to get the wheel width.

So you say that a 10.5" wheel will work fine in the front with a stock 295/35/18. Should I expect any rubbing with my car lowered max on the stock bolts ? See pics on my web page.

With the offset being different on the 10.5" wheel vs the 9.5" wheel, will the wheel/tire stick out a lot on the front now ?

Thanks a lot for your help !
Toque