Chrome olds rally wheels

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L92 OLDS

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Mar 30, 2012
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How wide is the rim? I have a feeling on my cutlass that extra 1/2 inch of bs would really make things rub under full lock

It would be nice if they offered an 8" or 10" width rim for the rear with 3" backspacing. The factory super stock III's were reported to have 3.5" and I have frame rub with drag radials. I'll have to measure one of my NOS spares.

wheel_guide.jpg
 

UNGN

Comic Book Super Hero
Sep 6, 2016
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Southlake, TX
It would be nice if they offered an 8" or 10" width rim for the rear with 3" backspacing. The factory super stock III's were reported to have 3.5" and I have frame rub with drag radials. I'll have to measure one of my NOS spares.

wheel_guide.jpg

Something is wrong if you are rubbing the frame with 3.5" BS and a 8" or 10" wheel. Even 275's shouldn't rub in a straight line with 3.5" BS on a 7" wheel and 8"/10" would move the tire further from the frame. A 10" wheel with 3.5" BS would put the tire into the outer fender on most G-bodies unless the car is jacked way up in back. 4.5-4.75" should be close to ideal with a 10" wheel.

Most GM factory 15X7's are closer to 3.9/4" BS than 3.5" and that .4" on such a narrow makes a huge difference. T-type Wheels are 3.75" BS and don't rub the frame with 275mm tires. GN wheels are 3.9" BS and do rub the frame with 275mm tires. As the Wheel size gets wider the tire overhang is less so the BS can be increased.
 
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84dragcutlass

Royal Smart Person
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Aug 20, 2009
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Something is wrong if you are rubbing the frame with 3.5" BS and a 8" or 10" wheel. Even 275's shouldn't rub in a straight line with 3.5" BS on a 7" wheel and 8"/10" would move the tire further from the frame. A 10" wheel with 3.5" BS would put the tire into the outer fender on most G-bodies unless the car is jacked way up in back. 4.5-4.75" should be close to ideal with a 10" wheel.

Most GM factory 15X7's are closer to 3.9/4" BS than 3.5" and that .4" on such a narrow makes a huge difference. T-type Wheels are 3.75" BS and don't rub the frame with 275mm tires. GN wheels are 3.9" BS and do rub the frame with 275mm tires. As the Wheel size gets wider the tire overhang is less so the BS can be increased.
So youre saying that if I got the 15 x 8 with the 41/2 bs on all 4 corners I should be ok? or even go with a 10 in wide rim in the back?
 

L92 OLDS

Comic Book Super Hero
Mar 30, 2012
2,872
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113
West Michigan
Most GM factory 15X7's are closer to 3.9/4" BS than 3.5" and that .4" on such a narrow makes a huge difference. As the Wheel size gets wider the tire overhang is less so the BS can be increased.
That's just BS ;)......Your numbers actually make more sense. I've measured them before and thought the actual number was closer to 4" but wasn't sure after reading 3.5" on 442.com I didn't think that a wider rim would bring the side wall in that much. Hmmm, maybe I should try an 8" rim with 4" BS...
 

UNGN

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Sep 6, 2016
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Southlake, TX
Out back, 4" BS is very close to perfect for a 8" wheel for all the different G-bodies. Some models have rounded, open fenders and can go with a little less BS (before a 275 hits the fender). It shouldn't rub the frame in a straight line with a 4" BS 8" wheel, with some slight contact during cornering. If anything, just a very small spacer is needed.

On the front, 8" wide 15" diameter wheels are tricky because at the perfect location between the fender and frame, they can hit the ball joints, control arms or Tie rod ends, BS more than 4" may make contact with the suspension bits on 15's. 8" wide wheels with LESS that 4" BS will hit the inner fenders with more than a 235mm tire on most G-bodies without work, so you can see why 15X8's are tricky in front. Larger diameter wheels are less of a problem as everything fits inside the wheel and 9" wide with near 5" BS will work.
 

UNGN

Comic Book Super Hero
Sep 6, 2016
3,048
3,264
113
Southlake, TX
So youre saying that if I got the 15 x 8 with the 41/2 bs on all 4 corners I should be ok? or even go with a 10 in wide rim in the back?

On back with up to 255's you should be OK. A 1/4" spacer might be needed at most. For 275's, you should use 4" BS to keep them off the frame. See above for the issues with the front with 15's. 4.5" is close to the "perfect" offset for 8" wide wheels in front, just not for 15" diameter wheels. 17X8's with 4.5" BS would fit with no issues, other than a slight, benign tire rub on the swaybar and frame at full lock.
 
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