Narrowing rear for zero offset wheels?
Thread Starter
Joined: Nov 2001
Posts: 10,060
Likes: 33
From: Canton, GA
Narrowing rear for zero offset wheels? Here's the deal. I'd like to build a 9-inch rear end that is slightly narrowed, but still allows factory positioning of the spring perches, shock mounts, etc.
- How much shorter would each axle tube need to be to use a zero offset wheel?
- How big of a wheel/tire combo could be run with mini-tubbing?
I know Bob at NRC has already done this, and Madman and Chris Sikora (Z9s) have also done similar. Can Moser or another prebuild this combo with stock mounting points?
- How much shorter would each axle tube need to be to use a zero offset wheel?
- How big of a wheel/tire combo could be run with mini-tubbing?
I know Bob at NRC has already done this, and Madman and Chris Sikora (Z9s) have also done similar. Can Moser or another prebuild this combo with stock mounting points?
The Bull
Joined: Jun 2002
Posts: 3,578
Likes: 2
From: Grand Rapids, MI
3" Shorter and would have a 4" backspacing on a 10" rim. You could retain all the factory mounts. Any more then that and you probably are encroaching on the lower control arms and spring perches.
The Bull
Joined: Jun 2002
Posts: 3,578
Likes: 2
From: Grand Rapids, MI
It's what I'm changing to. I currently run a 15x10 Weld AlumaStar with a 7" backspacing and it fits perfectly with no spacers. 3" off the axle will be 3" off the backspacing on my rim shell. I just need to order up two new rim shells from Weld and I'm all set. Kind of the nice thing with two piece rims! I just wish they made it with a bead locker, then it would look kick ***!
I'd assume if you minitub the car, debating that myself, you might be able to squeeze the tire in 1" and really tuck it in nicely on a 5" backspacing. I'm not sure what would get in the way though. I like the idea of a 4" backspacing myself. You would only need the tubs if you ran something that was like 13.5" wide. I've run 11.5 and 10.5 tires on this rim and they fit fine with no tubs.
I'd assume if you minitub the car, debating that myself, you might be able to squeeze the tire in 1" and really tuck it in nicely on a 5" backspacing. I'm not sure what would get in the way though. I like the idea of a 4" backspacing myself. You would only need the tubs if you ran something that was like 13.5" wide. I've run 11.5 and 10.5 tires on this rim and they fit fine with no tubs.
Last edited by DERTY; Dec 29, 2003 at 12:34 PM.
TECH Junkie
Joined: Nov 2001
Posts: 3,987
Likes: 0
From: Melbourne, FL
Originally Posted by KTamez
Narrowed 3.5" each side 7" total, w/ 4" BS wheels is the most I can see happening when you're dealing with a car using OEM LCA mounts. This is what I currently have.
I'm not 100% sure on everything, so I'm not getting in a particular hurry with anything.
George,
We have built several setups similar to this. 3" narrower per side is about the most you can go and still have enough room for the brake caliper. At this width, with a stock or slightly enlarged inner wheel tub, a 4" back space wheel fits perfect.
Take care.
We have built several setups similar to this. 3" narrower per side is about the most you can go and still have enough room for the brake caliper. At this width, with a stock or slightly enlarged inner wheel tub, a 4" back space wheel fits perfect.
Take care.
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I have no mini tubs but went in 1 3/4 per side. Do you plan on running a W tire? I do and had to make a custom set of small diameter solid 4140 LCA's so the tire would clear. I have a 5 in backspacing on my rim. It also took a fair amount of "massaging" in the wheel well to get things to fit though. Here are a few pics:
Tom
Tom
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Thread Starter
Joined: Nov 2001
Posts: 10,060
Likes: 33
From: Canton, GA
"W" stands for wide. Has the same measurements on the tire, but the tread width is greater, I think? 
Looks good Tom. I know Bob at NRC did mini tubs on his and he says it will accomodate a 29x14.5 tire. He also had to fab up custom LCAs for his to keep the stock mounting locations.
My main concerns are 1] stance, for stability, 2] rotor clearance, and 3] looks, plus it's nice to run a big old tire if the track sucks
Looks good Tom. I know Bob at NRC did mini tubs on his and he says it will accomodate a 29x14.5 tire. He also had to fab up custom LCAs for his to keep the stock mounting locations.
My main concerns are 1] stance, for stability, 2] rotor clearance, and 3] looks, plus it's nice to run a big old tire if the track sucks
TECH Resident
Joined: Aug 2003
Posts: 835
Likes: 0
From: aiken ,sc
rear hey todd, the rear in my car is a 12 bolt, its 56.5 " wide axle flange to axle flange, the brackets are in stock locations[this way no one can b***h about relocating brkts] ,the tires for car are 13.5x29.3 and 14.5x28 gtp,s as u saw they fit under nicely, the car is mini tubbed to rail , not noticable on inside has full interior ,back seat and all.i have 10" rims with 5" bs,i dont know about brakes as i have willwoods ps kit with e brake so they clear,the lwr arms are made of 1 1/4 cm tubing with cm hiems[same as we use on our 4 links,] the frt mount is also stock with spacers to move frt of arm,the bars are approxmatly 3/4" from sidewall of tire , i sent u picts of car being cut , i dont know how some guys are getting thier picts on without this attachment thing 
but i added some picts here bob 
and your right on w tire it is wider but in the begining some of the rules used to say sidewall designation must be 10.5[thats why it was made] now some classes measure tread with a go no go gauge so that tread cant be wider than its supposed to be no matter what side wall says 
but i added some picts here bob and your right on w tire it is wider but in the begining some of the rules used to say sidewall designation must be 10.5[thats why it was made] now some classes measure tread with a go no go gauge so that tread cant be wider than its supposed to be no matter what side wall says Last edited by NRC-Motorsports; Dec 30, 2003 at 08:14 AM.
Thread Starter
Joined: Nov 2001
Posts: 10,060
Likes: 33
From: Canton, GA
I got the pics Bob. To show them on the screen they have to be hosted on a server somewhere. If you would like me to host them, send them again and I will post them for you.
Tom, did you measure the back of the tire to the car, to see how much more you could have went?
BTW, Bilingsley sells LCA that retain the stock mounting points, but have offset bushings that move them inwards, it looks like maybe 3/4". http://www.billingsleyracing.biz/Cha...pension_GM.htm
I have already taken out the spring hump, & I believe it measured out to 3 1/2" from bulge of tire to the new plate replacing the hump. This is with the Convos 15x7.5 5" bs. I have 15x10 5" bs that will replace the 7.5", & with the same 15x10 tire on the new rim, I should have 1/2" left, after narrowing the rear 3" each side. I can always switch rims if need be, to a 4" bs.
BTW, Bilingsley sells LCA that retain the stock mounting points, but have offset bushings that move them inwards, it looks like maybe 3/4". http://www.billingsleyracing.biz/Cha...pension_GM.htm
I have already taken out the spring hump, & I believe it measured out to 3 1/2" from bulge of tire to the new plate replacing the hump. This is with the Convos 15x7.5 5" bs. I have 15x10 5" bs that will replace the 7.5", & with the same 15x10 tire on the new rim, I should have 1/2" left, after narrowing the rear 3" each side. I can always switch rims if need be, to a 4" bs.
On The Tree
Joined: Feb 2003
Posts: 179
Likes: 0
From: Grand Rapids, MI
Originally Posted by DERTY
It's what I'm changing to. I currently run a 15x10 Weld AlumaStar with a 7" backspacing and it fits perfectly with no spacers. 3" off the axle will be 3" off the backspacing on my rim shell. I just need to order up two new rim shells from Weld and I'm all set. Kind of the nice thing with two piece rims! I just wish they made it with a bead locker, then it would look kick ***!
If your looking for a bead lock wheel 15x10 or what ever size let me know becuase I can get ya taken care off.
I can hardly wait to get out this summer and beat up on some of these car's.
Take Care
Originally Posted by Gofast
Hey Derty,
If your looking for a bead lock wheel 15x10 or what ever size let me know becuase I can get ya taken care off.
I can hardly wait to get out this summer and beat up on some of these car's.
Take Care
If your looking for a bead lock wheel 15x10 or what ever size let me know becuase I can get ya taken care off.
I can hardly wait to get out this summer and beat up on some of these car's.
Take Care
On The Tree
Joined: Feb 2003
Posts: 179
Likes: 0
From: Grand Rapids, MI
Originally Posted by DERTY
Jim wants to whip on a few cars around here. We can add you to the list though.
On second thought Steve will probably want some of that action first seeing he found all that extra new power this winter. He can be the first to take ya down.
