back spacing and sizes

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72dustervs

72dustervs

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I am looking to run something like this setup 215/65 front and 255/60 rear , Will the rear size fit ? Would 3 3/4 or 4.5 back spacing work ? 72 Duster with a large 11" rotors front , 8 3/4 rear installed ,,looking at Torq thrust polished or the Torq thrust D Black or maybe good ole Cragar's but open to any suggestions on which wheel some like better than others ?
 
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Depends on the rim width and diameter. I'm assuming 14-15"? 17" would be better for tire selection and fitment.
 
Well based on the rim choices I’m gonna say big bolt pattern, 15” wheels right?

For reference, both BBP and SBP rotors were 10.98” so people will call them 11”. There’s also a larger BBP rotor that also works that’s 11.75”, so saying “large 11” rotors” is misleading. You could make an argument for 3 different rotors with 2 different bolt patterns based on that statement.

Is the 8 3/4 rear from an A-body? Is it running redrilled axles and brakes or has it been swapped to BBP axles with the appropriate BBP brakes? Because that changes the track width.

In the front a 215/65/15 is 26” tall, which is pretty tall and may cause clearance issues on the corners of the fender openings. That will depend a lot on the backspace used in the front, and also on the ride height of the car
 
Should have been more detailed , its 15 or 16 inch rims , 11.75 front rotors and bb rear end , was built for an a-body , new axles bb pattern an brake set up and ESPO springs an shackles an bushings

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15x7 with a 4.25” backspace up front with up to a 225/60/15 for the tire. If you use less backspace then that you’ll have to knock it off the tire width.

15x7 4.25” or 15x8” with a 4.5” backspace in the back. 255/60/15 can go on either one and should have room. With the 15x8” a 275/60/15 will fit most Dusters/Demons/Dart Sports but some cars are tighter than others and ride height, rear sway bar, and spring choice can make a difference for the 275’s.

And as a final disclaimer the body tolerances on these cars are pretty loose, so, it’s always best to measure your own car to confirm.
 
72bluNblu said:
15x7 with a 4.25” backspace up front with up to a 225/60/15 for the tire. If you use less backspace then that you’ll have to knock it off the tire width.

15x7 4.25” or 15x8” with a 4.5” backspace in the back. 255/60/15 can go on either one and should have room. With the 15x8” a 275/60/15 will fit most Dusters/Demons/Dart Sports but some cars are tighter than others and ride height, rear sway bar, and spring choice can make a difference for the 275’s.

And as a final disclaimer the body tolerances on these cars are pretty loose, so, it’s always best to measure your own car to confirm.
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what do you think about a 15x10 rim on rear ?
 
72dustervs said:
what do you think about a 15x10 rim on rear ?
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I mean, it’ll probably fit. But with the springs in the stock location it doesn’t get you anything, a 275/60/15’s “measuring rim” is a 15x8”. So really it just makes the backspacing more difficult, you’d need a 15x10” with a 5.5” backspace, which really doesn’t give you enough spring clearance. Meanwhile a 5” backspace might not give you enough quarter clearance. The 275/60/15 will be a bit on the stretched side. Not crazy or anything but there’s no real reason for it.
 
72bluNblu said:
I mean, it’ll probably fit. But with the springs in the stock location it doesn’t get you anything, a 275/60/15’s “measuring rim” is a 15x8”. So really it just makes the backspacing more difficult, you’d need a 15x10” with a 5.5” backspace, which really doesn’t give you enough spring clearance. Meanwhile a 5” backspace might not give you enough quarter clearance. The 275/60/15 will be a bit on the stretched side. Not crazy or anything but there’s no real reason for it.
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I remember the guys that ran 15x10's on the back of their Dusters. Not a good look unless you mini tub and stuff them up inside. Back then a pair of air shocks would get you there. Not a good plan.

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toolmanmike said:
I remember the guys that ran 15x10's on the back of their Dusters. Not a good look unless you mini tub and stuff them up inside. Back then a pair of air shocks would get you there. Not a good plan.

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I may have a set close that I may be able test fit , if they look like that then no not good idea,,thanks
 
If I can find 15x 9 wheels what would a could back space be for the rear setup ? And would they be to much for the front ? probably would be but might be good option for rear , seeing some places that will produce these sizes
 
toolmanmike said:
I remember the guys that ran 15x10's on the back of their Dusters. Not a good look unless you mini tub and stuff them up inside. Back then a pair of air shocks would get you there. Not a good plan.

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Yup, that’s about how you have to do 15x10’s if you’re going to run enough tire to actually use the 10” rim.

With a 275 you might be able to stuff it into the quarter, but you don’t need 15x10’s for 275’s either. Just easier to run the 15x8” they’re supposed to be mounted on.
72dustervs said:
If I can find 15x 9 wheels what would a could back space be for the rear setup ? And would they be too much for the front ? probably would be but might be good option for rear , seeing some places that will produce these sizes
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They’d work in the rear, you’d need a 5” backspace to make it work. Again, it really doesn’t buy you anything. A 275 is the widest tire you can run with the stock spring locations unless you hang them out of the quarters. And a 275 is perfectly happy on a 15x8”.

Not happening in the front. Even 15x8’s don’t work in the front. You can’t run more than 4.5” backspace because the rim hits the brakes/suspension. Even 4.5” is pretty marginal for brake/suspension clearance. And with a 15x8” that’s not enough backspace to get the wheel under the fender with any width tire that’s worth running the 8” rim. With 4.25 to 4.5” of backspace on a 15” rim the most you’re going to fit on most of these cars is a 225, which fits easily on a 15x7”.
 
72bluNblu said:
Yup, that’s about how you have to do 15x10’s if you’re going to run enough tire to actually use the 10” rim.

With a 275 you might be able to stuff it into the quarter, but you don’t need 15x10’s for 275’s either. Just easier to run the 15x8” they’re supposed to be mounted on.


They’d work in the rear, you’d need a 5” backspace to make it work. Again, it really doesn’t buy you anything. A 275 is the widest tire you can run with the stock spring locations unless you hang them out of the quarters. And a 275 is perfectly happy on a 15x8”.

Not happening in the front. Even 15x8’s don’t work in the front. You can’t run more than 4.5” backspace because the rim hits the brakes/suspension. Even 4.5” is pretty marginal for brake/suspension clearance. And with a 15x8” that’s not enough backspace to get the wheel under the fender with any width tire that’s worth running the 8” rim. With 4.25 to 4.5” of backspace on a 15” rim the most you’re going to fit on most of these cars is a 225, which fits easily on a 15x7”.
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I like a old school look deep dish , only reason I would go 15x9 ,,I have had a 14x10 on a dart back in the day was on a mag style looked great even if it was past the fender well , thanks for your help
 
QuickDart360 said:
Your dart have a 8 3/4 or 8 1/4? 8 1/4 is narrower.
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I removed the factory 8 1/4 BBP 321:1 sure grip. Gave it away since I have lots of 3rd member's.
Installed an A Body 8 3/4, with Moser axles with BBP and 11" drums from a Truck, Van, Sea Body.
 
I do have a spare A Body 8 3/4 I picked up at You Pull It. Was 80 bucks with a power lock 3rd member.
And a Doctor Diff kit. So going to move spring's But they did fit but are tight.
think I need the room since these are 15x8 Ram Charger 4.25 back space and would like to use them with 275-60-15
My other wheels are 4.5 back space


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I run a 10 inch/5 back on my dusters and Demon 9 x 30 Slicks.
Spring not moved as it is illegal in Stock,
 
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