Backspacing question

[tt455]

Is 4-7/8" too much BS on a 15 x 8.5 wheel? Tire would be 275/60 going on an 87 Turbo T car. Ty

 

[JC'sGN]

it will be close.... but you can always go back out with a thin spacer.

 

[Turbo6inKY]

Should be fine.

If you can, find somebody with an old tire they'll give you and get it mounted on your wheels and test fit it to be sure.

 

[tt455]

Thanks guys

 

[TurboTGuy]

Tight, Tight, Tight.........

 

[MNwe4]

I'll echo replies here. 275/60 on 15x8 w/ 4" BS is 1/2" from frame rail on each side on my car. Going with 7/8" more BS but only a 1/2" wider wheel I bet would rub when cornering. Small spacer and extended lugs might get you there.

For other reference I looked at a few other club cars last weekend with 275/60 on 15x10's with 4.5" BS and they had around 3/4" clearance to the frame.

 

[SCOOBY DOO]

It won't fit. Ran a 4.5 inch backspace with a 7/32 spacer with the 275/60/15 DR on my car.

 

[Scarab]

It won't fit. Ran a 4.5 inch backspace with a 7/32 spacer with the 275/60/15 DR on my car.

how much room did you have ? did you have to use a spacer? where your fender lips rolled?

 

[SCOOBY DOO]

how much room did you have ? did you have to use a spacer? where your fender lips rolled?

I listed the spacer...lips were not rolled. Enough space it cleared the frame.

 

[SCOOBY DOO]

Keep in mind I used aluminum rear drums which are thicker than the cast iron.

 

[SCOOBY DOO]

 

[Scarab]

So I am going to go with a 15x9 with 4.75 with a drag radial 275/60/15, no rolled lips and no notch. Will it fit? Billet specialties said it would.

 

[turbocamino1]

If you look at the section width's of drag radials you will see a variance between hoosier and M/T..and between their tires models...the hoosier lists the slimest,fwiw.

 

[turbocamino1]

... betting a 9" with the 275/60 with 4.75 back ,will rub the frame. Fwiw,, 8" rim 4" back fits very nice and will give an honest 10" of rubber to the road.

 

[SCOOBY DOO]

So I am going to go with a 15x9 with 4.75 with a drag radial 275/60/15, no rolled lips and no notch. Will it fit? Billet specialties said it would.

Aluminum or cast iron drums?

 

[Scarab]

Aluminum or cast iron drums?

We are now going with a 15x9 with a 4.50 back space.

 

[Scarab]

Iron drums

 

[SCOOBY DOO]

Iron drums

I'm betting dollars to donuts you'll need a spacer like I did. All you can do now is bolt it on and see where you're at. As I said previously, I knew mine would fit with a spacer as Grumpy ran the same wheel width/tire/backspace.

 

[1986 Buick GX1]

I'm betting dollars to donuts you'll need a spacer like I did. All you can do now is bolt it on and see where you're at. As I said previously, I knew mine would fit with a spacer as Grumpy ran the same wheel width/tire/backspace.

This thread has changed direction a couple times, but with a 9” (4.5” B.S.) wheel it will move the tire centerline out 1/2” compared to an 8” (4.5” B.S.) wheel and should pull the sidewall off the frame about the same.
I’ll add this here as it’s posted on his other thread as well.
This would be compared to his existing tire and wheel setup and based on having 1/2” clearance to the frame.
You’re right, if he needs more room he can go to aluminum drums or add a small spacer.

 

[SCOOBY DOO]

... betting a 9" with the 275/60 with 4.75 back ,will rub the frame. Fwiw,, 8" rim 4" back fits very nice and will give an honest 10" of rubber to the road.

You're correct. An 8 inch rim with a 4 inch backspace in optimum for these cars.