Rim Back Spacing Question
Thread Starter
Safety Car
Joined: Aug 2000
Posts: 3,909
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From: Clymer PA
Rim Back Spacing Question
What is the stock wheel back spacing on a 1976 Corvette? I'm thinking about getting a pair of Weld Pro Stars for the back to mount a pair of slicks on to replace my stock steel Rally rims and eliminate some rotational mass. I have a pair of polished 15x3 Centerline Autodrags for the front already. Thanks in advance 
Team Owner
Joined: Jul 1999
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From: Orange Park Florida
What ever you do, just do it smart....and keep the wheel centerline the same as what you got....you can use a tape, and I suggest you do....
wider wheels can go to 9.5 inches...that being 3/4 into inside, and of course 3/4 to outside....they will clear sway bars and frame...
assuming you move the ebrake bracket off the T-arm....
so you CAN get 10" of rubber on there without going crazy...
but you need spec the wheels and tires, and pay attention to the obvious....
destroying the wheel centerline IMO...and I suspect most engineers would agree with me....puts mucho more stress on the wheel hubs than I would consider reliable for a street machine...
Drag race ONLY, yeh, well maybe...usually no several lateral loading,....
I am one of the few bugs on this point, especially in the rear...as those hubs have no purchase on the lever...so they in trouble quick....
wider wheels can go to 9.5 inches...that being 3/4 into inside, and of course 3/4 to outside....they will clear sway bars and frame...
assuming you move the ebrake bracket off the T-arm....
so you CAN get 10" of rubber on there without going crazy...
but you need spec the wheels and tires, and pay attention to the obvious....
destroying the wheel centerline IMO...and I suspect most engineers would agree with me....puts mucho more stress on the wheel hubs than I would consider reliable for a street machine...
Drag race ONLY, yeh, well maybe...usually no several lateral loading,....
I am one of the few bugs on this point, especially in the rear...as those hubs have no purchase on the lever...so they in trouble quick....
Thread Starter
Safety Car
Joined: Aug 2000
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From: Clymer PA
Yes the e-brake brackets are gone. I run 28x11.5x15 Mickey Thompson ET streets which is slightly less than 10" of rubber. I really just want to get the same exact 15x8 rim with the same backspacing....just in the Weld Pro Star style.
Thread Starter
Safety Car
Joined: Aug 2000
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From: Clymer PA
Originally Posted by goinbroke
Stock is 4" I believe.
. Now someone said that stock backspacing is 4". So if that is the case couldn't I buy a pair of 15x8 Weld Pro Stars with 4" back spacing and be good to go???
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Thread Starter
Safety Car
Joined: Aug 2000
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From: Clymer PA
Originally Posted by 69 N.O.X. RATT
Slicks?? is your rear stock Shane??
P.S. I do have halfshaft loops that Norval was kind enough to give me just in case things start breaking.
Racer
Joined: Sep 2003
Posts: 258
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From: Memphis TN
Back spacing of stock rims
I just had to go through a crash course on this when I ordered my new AR Torque Thrust II's for my 74. I wanted to stay with the stock wheel size and back spacing so I thoroughly researched the subject, including measuring the stock wheel myself. It turns out that although the stock (Rally) wheels on mid-70's Vettes are indeed 15x8 with 4" of back spacing, this is only the width BETWEEN THE INNER EDGES OF THE RIM. The wheel is actually 9 INCHES WIDE TOTAL, as measured from the outide edges of the rim. This means that there is a total of 5" of width on the OUTSIDE of the mounting surface, giving the rim one-half inch of "negative offset". If it had 4.5" of back spacing, it would be a "centered" rim and would have zero offset.
I also measured the clearance to the caliper with the rim on my car and I believe you would have clearance problems if you ran a rim with more than 4 inches of backspacing, unless you removed the e-brake arms.
Hope this clears things up.
I also measured the clearance to the caliper with the rim on my car and I believe you would have clearance problems if you ran a rim with more than 4 inches of backspacing, unless you removed the e-brake arms.
Hope this clears things up.
Burning Brakes
Joined: Nov 2004
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From: Kansas
Originally Posted by bence13_33
I feel like I am missing something here. I'm not trying to be difficult I swear . Now someone said that stock backspacing is 4". So if that is the case couldn't I buy a pair of 15x8 Weld Pro Stars with 4" back spacing and be good to go???
. Now someone said that stock backspacing is 4". So if that is the case couldn't I buy a pair of 15x8 Weld Pro Stars with 4" back spacing and be good to go???I tried a set of the Cragar stars same as Weld and didn't clear,so ad that to your figures.I'm not 100% sure maybe 90%.
Melting Slicks
Joined: Jun 2002
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From: Orrtanna Pa.
I have Weld Draglites.The mounting flange on the wheel is flat,and will not clear the brakes without a spacer. I ordered 15x9's with 5 1/2 " backset,and installed a set of VB&P 1/1/4" wheel adaptors. This puts the effective backset to 4 1/4" (4" is stock) and my P295 50 15's fit completely under the fender with no clearance issues. (10" tread)
Race Director
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From: Corsicana, Tx
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I've been using a set of 8" rally's on mine with the 10.5x28" slicks. If I'm not mistaken they measured 3-3/4" backspacing. That was laying a straightedge across the lip and measuring down to the center area. I moved the e-brake bracket and the slicks are pretty close to trailing arm and polish it slightly on the front edge.
I just took off the TTII's with 3-3/4" backspacing and they fit perfect. I just installed Cragar SS's with 4-1/4" backspacing and they are a PITA. Had to use spacers to clear calipers anyway but that got tire back away from trailing arm..which is stock.
You gotta be careful going to far inward unless you have a shortened spring and offset arms.
I have a buddy with some old Cragar Super Tricks that I was going to use, but they had 4.50" backspace and no way they would clear. Might have with offset arms....don't know.
Maybe this helps.....
JIM
PS- Bence-You living in Atlanta these days? I go there a lot for work..in fact I'll be there next Monday.....wanna meet up sometime?
I just took off the TTII's with 3-3/4" backspacing and they fit perfect. I just installed Cragar SS's with 4-1/4" backspacing and they are a PITA. Had to use spacers to clear calipers anyway but that got tire back away from trailing arm..which is stock.
You gotta be careful going to far inward unless you have a shortened spring and offset arms.
I have a buddy with some old Cragar Super Tricks that I was going to use, but they had 4.50" backspace and no way they would clear. Might have with offset arms....don't know.
Maybe this helps.....
JIM
PS- Bence-You living in Atlanta these days? I go there a lot for work..in fact I'll be there next Monday.....wanna meet up sometime?
Racer
Joined: Sep 2003
Posts: 258
Likes: 1
From: Memphis TN
Torque Thrust II part numbers
Originally Posted by VCuomo
memphis03EB - So did you end up with AR TTII part number 5055861 rims?
Since they were special-order custom-built wheels, I actually don't know the part number but they are model number CL205.
Thread Starter
Safety Car
Joined: Aug 2000
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From: Clymer PA
PS- Bence-You living in Atlanta these days? I go there a lot for work..in fact I'll be there next Monday.....wanna meet up sometime?
I have been living in Atlanta for about 2 years. However I met a girl down here and she said that she'd be willing to move home with me...I'm moving home November 5th (this Sunday) otherwise I would have met up with you for sure. I'll be able to start drag racing and working on the car again once spring weather hits. Here's a picture of my baby (I'm sorry I love to brag about her, she's awesome).
Melting Slicks
Joined: Apr 2000
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From: Ft. Walton Beach, Fl USA
Originally Posted by bence13_33
I feel like I am missing something here. I'm not trying to be difficult I swear . Now someone said that stock backspacing is 4". So if that is the case couldn't I buy a pair of 15x8 Weld Pro Stars with 4" back spacing and be good to go???
. Now someone said that stock backspacing is 4". So if that is the case couldn't I buy a pair of 15x8 Weld Pro Stars with 4" back spacing and be good to go???
Race Director
Joined: Jan 2000
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From: Corsicana, Tx
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2017 C2 of Year Finalist
Hey she's a cutie!! Congratulations!!
Oh well....you'll be ready to bring it to the Forum Cruise In come next May right?? Finally?????
JIM
Oh well....you'll be ready to bring it to the Forum Cruise In come next May right?? Finally?????
JIM
Team Owner
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From: Reno Nevada
2024 C3 of the Year Finalist- Modified
I have weld 10X15 with 4.5 BS with my 10X28 goodyear slicks. Without my 420# spring they would hit the stock 79 body. You would have to have modded fenders.
She is a cutie! It would be nice to be young again. I have a foxy 21 year old dau! She knows all about Alki injected dragsters and GoKart raced. She is a Snow board bum. I had High hopes for grad or medical school.
Now I just tell her it's just as easy to love a rich man as a poor one
The Wife (driving)and daughter in front of our house - Her Firebird
She is a cutie! It would be nice to be young again. I have a foxy 21 year old dau! She knows all about Alki injected dragsters and GoKart raced. She is a Snow board bum. I had High hopes for grad or medical school.
Now I just tell her it's just as easy to love a rich man as a poor one
The Wife (driving)and daughter in front of our house - Her Firebird