Rear end width with full notch 15x10

[Tz44]

I’m getting a 9” built for my regal and need to figure out how much I can narrow it from stock (g body) width. Originally I wanted to see if I could fit 15x12 street lites on it with a full frame notch and tubs but I can’t seem to find anyone that has been able to without moving the frame rails in. It almost seems like it’s more of a hassle than what it’s worth so I’m thinking 15x10s now.
I’ve always used stock width rears in the past so this is kind of new to me. I was planning on just 1” shorter per side so the wheels would tuck under the fender nicely without too much backspacing.
Does anyone here have experience with narrowing theirs? How much did you narrow it and what kind of backspacing are you running?
thanks for any help

 

[scoti]

I’m getting a 9” built for my regal and need to figure out how much I can narrow it from stock (g body) width. Originally I wanted to see if I could fit 15x12 street lites on it with a full frame notch and tubs but I can’t seem to find anyone that has been able to without moving the frame rails in. It almost seems like it’s more of a hassle than what it’s worth so I’m thinking 15x10s now.
I’ve always used stock width rears in the past so this is kind of new to me. I was planning on just 1” shorter per side so the wheels would tuck under the fender nicely without too much backspacing.
Does anyone here have experience with narrowing theirs? How much did you narrow it and what kind of backspacing are you running?
thanks for any help

First.... Ride height plays a lot into decisions. I know 15x10's w/a frame notch (to the seam) would utilize approx. 6"bs to clear a slightly trimmed/rolled fender lip; a stock width rear end, & a lowered ride height. So w/that as a starting point strictly for the math:
2" narrower (1" per side) would put things @ 15x10 w/a 5" bs
4" narrower (2" per side) would be 15x10 w/a 4" bs

Adjust the math back/forth depending on wheel BS availability/price. For cars that aren't 'low', you definitely can get away w/different combos. For reference, this car has 20x10" wheels, 6"bs, 295/40/20 @ 29" tall, & is notched to the frame seam.

 

[Tz44]

First.... Ride height plays a lot into decisions. I know 15x10's w/a frame notch (to the seam) would utilize approx. 6"bs to clear a slightly trimmed/rolled fender lip; a stock width rear end, & a lowered ride height. So w/that as a starting point strictly for the math:
2" narrower (1" per side) would put things @ 15x10 w/a 5" bs
4" narrower (2" per side) would be 15x10 w/a 4" bs

Adjust the math back/forth depending on wheel BS availability/price. For cars that aren't 'low', you definitely can get away w/different combos. For reference, this car has 20x10" wheels, 6"bs, 295/40/20 @ 29" tall, & is notched to the frame seam.

Appreciate the info. After looking at it pretty close tonight I think 2” on each side is the most I could possibly take off and still have it fit even after notching. I want it to sit low and rotors hitting the frame would be a big concern at that width. I’m leaning towards 2-3” total now.
Does the car in the pictures have stock wheel tubs? Just curious.

 

[superbon54]

17x11 with 7” backspace and the wheels are out 1/2” from stock. The body should be going back on in the next couple days so I can get some more pics then.

I notched with 1/4” plate and reinforced with plate on the backside of the frame.

 

[Tz44]

Looks amazing. Can’t wait to see it with the body back on it.
Stock width rear end?

 

[scoti]

Appreciate the info. After looking at it pretty close tonight I think 2” on each side is the most I could possibly take off and still have it fit even after notching. I want it to sit low and rotors hitting the frame would be a big concern at that width. I’m leaning towards 2-3” total now.
Does the car in the pictures have stock wheel tubs? Just curious.

It did not. They were cut out to allow a taller tub height so the car could go lower. From memory, the tub width wasn't an issue as much as the corners (where they curved toward the body) that were the concern. It wound up w/some CA Chassis-Works style tubs in it.

I know the guy that has it now said if he had it to do over, he wouldn't have cut them out & would have just went as is.

 

[superbon54]

Looks amazing. Can’t wait to see it with the body back on it.
Stock width rear end?

It was build 1” wider to get the 315 tires in on the wheels I wanted without spacers.

 

[Tz44]

Makes sense. The wheels look perfect.

 

[superbon54]

Thanks! The whole car is being built as an 80s look with modern vibe, which limited my wheel choices.

 

[JAMCAR223]

Superbon54, could you take a closer picture of the rear frame brace”s attachment method?