Wheel Backsacing

[wantcrewaturbo6]

I am new to the board. I have just picked up a 87 T and will be looking to put aftermarket wheels and tires on it. I need help with the backspacing on the wheels. I will be using 15 X 7 on the front with a 225/60/15 and 15 X 8 with a 275/50/15 on the rear what backspacing should I use 3.5, 4.0 ??? Thanks for the help.

 

[.38 special]

Some people may disagree, but mine measured so that about 5 inches would be the absolute max. but stay at 4.5 or under just to be sure, so what you are questioning should be fine just pick out what suits your taste.

 

[slamming 6]

I run 275-60-15s on a 8in rim with 4in back space and have 3/4in clearence on the inside and about the same outside and thay dont rub 4.5 might be too close.

 

[TheSwede]

What is the stock backspacing in the -87 GN?

 

[turbosam6]

4.5 will be too close. 4 or 3.5 will work, with 3.5 getting you pretty close to the lip. Every one of these cars is different. Most of them don't have even axle spacing. I like the 4 inch. I have 3 sets of rims, and one set is 4.5. I have 255 60's on those rims and still have to run spacers to keep them off the frame.

 

[b4black]

Originally posted by TheSwede
What is the stock backspacing in the -87 GN?

4"

 

[TheSwede]

b4black>> Thanks!

front and rear? (i forgot to mention that)

i'm looking for some aftermarket rims, 7x15 inch in front and 10x15 inch rear.

going to put as large as possible slick tyre in the rear

Gotta have some grip. not quite fun to spin up to about 50 mph (90kph) when the boost comes

And not so fun to start with no boost at all.
and about a couple of feet out, all boost comes, and the rear 255's will spin.

 

[van460]

i have a 28-12.5 et street on stock rims and run about 3/8 spacers to get off frame still rubs when turn though so i know you can fit this tire it is as big as a 28-10.5 slick if you are thinking about slicks. i run et street so i can drive on street and they hook just as good.

 

[van460]

also i have did the resaerch on rims and your best bet is a 8.5 with 3-3/8 back spacing a ten will stick out to the lip to much, we have run well into the 6.00 and 5's in the eight on 8-8.5 rims so dont worry about the width. van

 

[Buicksx2]

FWIW I run a Weld prostar 15x10 rim with a 4.5 BS on both my wifes TR and slicks on my car and they do not rub at all.

HTH

 

[PhilM]

i have autodrags 8.5" by 15"s on back with 4 7/8 B.S. and they are CLOSE! to the fender lips. I still have to roll mine. 255 60's rub on stock lip over bumps whereas 245 60's are better (dont rub). Also, i have more space between tire and frame than i like, so id say 4.5 for 8.5 wheel is good but it sux that centerline doesnt have this BS option. oh well.

 

[.38 special]

I think that every answer is different for two reasons:
1. Every car is just a little different and hardly any of the rear ends are perfectly centered.
2. Also, wheel manufacturers don't include the lip of the wheel when measuring the backspacing. They measure from the mounting pad to the bead seal. So when we sit down and measure our own backspacing with a straight edge, it is different than what the manufacturer stated. So I think some people post what the actual backspacing is and some what the manufacturer said. Just my $.02 though.

 

[b4black]

Originally posted by TheSwede
b4black>> Thanks!

front and rear? (i forgot to mention that)

i'm looking for some aftermarket rims, 7x15 inch in front and 10x15 inch rear.

All four steel 86/87 GN rims are the same;15x7 with 4" BS. Up front I have 235/60R15's (on the steel GN rims) and they rub the frame just a little at full lock. I have no clue about 10" wheels.

HTH

 

[tazgn]

Every car is different as others have said. Mine takes 4" on one side and 4.5" on the other side because I have one of those "special" cars that don't have the body centered on the frame.

I would do like I did. You know the stock GN wheels have 4" of backspacing. So measure from the inside of your wheels now and find out how much room you have to the frame. Then you know the max backspacing you can go with. You can also do this for the outside with the fender lip.

Also just want to mention that you really need to know the total tire width too... I had BFG radial T/A's (275-50-15's) on the stock rims and they would rub a little because the sidewalls ballooned out so much. So my backspacing for the wheels I have now was determined a lot by the tire width, NOT the wheel width.

Derrick