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Topic: Wheel Question

in Forum: C3 General Discussion


Wheel Question

Posted: 5/29/12 7:20am Message 1 of 48
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Cramerton, NC - USA
Joined: 8/22/2006
Posts: 1094
Vette(s): black 1982 coupe slate gray interior, 350 crossfire, 1985 fuel pump, Steeroids R&P conversion

I’ve been considering changing the wheels on my 82 and need input from this knowledgeable group.  I know the backspacing on the stock wheel is 4 inches but I’m having  difficulty finding exactly what Im looking for with a 4 inch backspace.  I’m considering the wheels in the link below from Summitt but they are 3.75 inch backspace and an offset of -19.00mm. First of all, will these wheels work on our cars?  How will that small difference in backspace affect the geometry of the rear suspension and handling?  I am not interested in going with a larger tire than the stock 15 inch.  I recently bought new tires and don’t plan on buying a new set for quite a while.

http://www.summitracing.com/parts/SUM-141-5861GM19/

|UPDATED|5/29/2012 7:20:10 AM (AZT)|/UPDATED|



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Re: Wheel Question

Posted: 5/29/12 9:20am Message 2 of 48
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Holland Patent, NY - USA
Joined: 6/3/2008
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Vette(s): #1 *1980 White, Red interior 14,000 mile #2 *1980 Red, Oyster interior 93,000 miles Resto project car, rebuilt to 383 stroker
Chip, those look real close to what Dick and Jill Countryman have on their vette...no?
Evil Smileebo




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Re: Wheel Question

Posted: 5/29/12 9:58am Message 3 of 48
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Cramerton, NC - USA
Joined: 8/22/2006
Posts: 1094
Vette(s): black 1982 coupe slate gray interior, 350 crossfire, 1985 fuel pump, Steeroids R&P conversion
Yes, very similar but I think they are running 16 inch on theirs.  This whole backspace and offset thing has me a bit puzzled Confused


Re: Wheel Question

Posted: 5/29/12 10:54am Message 4 of 48
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 This depicts offsets. An 8 inch wheel with a 4 inch backspace would then equal a zero offset due to the fact that it's centered. The wheel 3.75 backspace will actually be a negative 19mm. This would actually move the wheel/tire a 1/4" outward toward the fender lip. You probably have enough clearance for that.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 




corvette440hp

Re: Wheel Question

Posted: 5/29/12 6:28pm Message 5 of 48
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Belvidere, IL - USA
Joined: 10/24/2004
Posts: 440
Vette(s): 1977 Black T-Top ZZ4 5Sp 16in Wheels
Hi Chip, 9 years ago when we redone the car. The 15 inch rims with 3.75 back space would hit the calibers.That was American Racing wheels, that's why I went with 16 inch for the 4 inch back space. Dick


Re: Wheel Question

Posted: 5/30/12 3:15am Message 6 of 48
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Cramerton, NC - USA
Joined: 8/22/2006
Posts: 1094
Vette(s): black 1982 coupe slate gray interior, 350 crossfire, 1985 fuel pump, Steeroids R&P conversion
Thanks for your replies guys.  Dick, your information was especially useful.  I think Ill just be keeping the stock wheels for now unless I can find some 15s with the proper backspace.


Re: Wheel Question

Posted: 5/30/12 9:03am Message 7 of 48
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Manteca, CA - USA
Joined: 11/20/2005
Posts: 3623
Vette(s): 1978,two tone,Metalic Rootbeer & gold 1975 L48 4 speed
The last set of wheels I bought were from Les Schwab, American racing look alikes, 15x8 with a 3.75 back spacing. My concern was the leaf spring clearance and these wheels left me about 1/2" on each side w/ 255/60x15 tires.

|UPDATED|5/30/2012 9:03:30 AM (AZT)|/UPDATED|



Re: Wheel Question

Posted: 5/30/12 3:21pm Message 8 of 48
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Burke, VT - USA
Joined: 1/23/2002
Posts: 7315
Vette(s):
SOLD - "The Toy" - '70 Convertible
SOLD - "The Beast" - '90 ZR-1 (#682)
SOLD - "Betty" - '28 Ford Model A Tudor
SOLD - "BLKBRRD" - '78 Pontiac Trans Am
"BLUBYU" - '04 Coupe
When I moved up to the 16" wheels on "The Toy" I needed to have some custom spacers made to get to the correct offset.  Zen-Master Ken (kstyer) told me that as long as the wheel is centered the thickness of the spacer doesn't matter and it won't upset the suspension geometry.  So if you really like the wheels a 1/4 inch spacer should be pretty easy to find.


Jim Olson 

"The Toys"...!!!  Save the Wave!

Where I've been in a Corvette...!!!

Re: Wheel Question

Posted: 5/31/12 3:16am Message 9 of 48
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Cramerton, NC - USA
Joined: 8/22/2006
Posts: 1094
Vette(s): black 1982 coupe slate gray interior, 350 crossfire, 1985 fuel pump, Steeroids R&P conversion
Thanks guys, Im still looking at my options here and appreciate your input.


Re: Wheel Question

Posted: 6/4/12 11:09am Message 10 of 48
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Hi All,
I'm new to this forum and have taken an interest in this thread.  The discussion about backspacing and negative offset doesn't seem correct to me.  If an 8" wheel has a 4" BS then it has a Zero offset.  So if an 8" wheel has a 3.75 BS then it would have a negative 0.25 offset.  That would be -6.35mm offset not -19mm.  Am I missing something here?

Also, if the wheel has a 3.75 BS, a 1/4" spacer won't fix this.  It would make the BS 3.5".

I'm trying to understand all this wheel terminology because I'm installing a set of C5 wheels on my '73.

Thanks everybody,
John



1973 BB 4-Speed Coupe Project Car
2009 Z06 Mostly Stock

in Forum: C3 General Discussion


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