18x9.5 Rear and 17x7 front
- Thread starter Josh Byrd
- Start date
-
- Tags
- wheels. rims
1986 Buick GX1
GX1 #001 [The One and Only]
- Joined
- Apr 24, 2015
I won't comment on the front as I'm not sure.
As to the rear however, I have 17x9 4.5 backspace (4 5/8 b.s. w/ SSBC rear disc brakes 1/8" thicker rotor hat) w/ 285/40's and very slight rubbing on hard turns using stock upper control arms and stock bushings.
The Riddler 9.5 wide wheel 0 offset calculates like this:
The wheel is 9.5 wide on the inside of the bead, the wheel has an unknown rim lip thickness, but we'll figure 1/4".
0 offset is center of the width or 1/2 the 9.5 = 4.75 + .25 lip thinkness = 5"? backspace.
Knowing the overall width of the wheel would be most useful, 1/2 the overall width = backspace.
The wider wheel will pull the tire away from the frame .25 (as comaired to mine) and a narrower tire will make more room as well.
On my car it looks like an 1/8" or 1/4" spacer maybe needed to fit the riddlers on the rear.
Turbo6inKY says he has seen guys run 18x9.5 5" backspace wheels w/ 275/35's front and rear (stock brakes), but I think that depends on the car. It depends on how the body sits on the frame and if you're willing to reposition it and how stable the rear axle is.
Hopefully he will provide his insight.
As to the rear however, I have 17x9 4.5 backspace (4 5/8 b.s. w/ SSBC rear disc brakes 1/8" thicker rotor hat) w/ 285/40's and very slight rubbing on hard turns using stock upper control arms and stock bushings.
The Riddler 9.5 wide wheel 0 offset calculates like this:
The wheel is 9.5 wide on the inside of the bead, the wheel has an unknown rim lip thickness, but we'll figure 1/4".
0 offset is center of the width or 1/2 the 9.5 = 4.75 + .25 lip thinkness = 5"? backspace.
Knowing the overall width of the wheel would be most useful, 1/2 the overall width = backspace.
The wider wheel will pull the tire away from the frame .25 (as comaired to mine) and a narrower tire will make more room as well.
On my car it looks like an 1/8" or 1/4" spacer maybe needed to fit the riddlers on the rear.
Turbo6inKY says he has seen guys run 18x9.5 5" backspace wheels w/ 275/35's front and rear (stock brakes), but I think that depends on the car. It depends on how the body sits on the frame and if you're willing to reposition it and how stable the rear axle is.
Hopefully he will provide his insight.
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