Will 15x8 steelies fit a 72 out back?

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djais1801

djais1801

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I'm finalizing a deal on a 72 A-body.
I have a set of steelies from my roadrunner.
15x6.5 (4 1/2 BS)
15x8 (4 1/2 BS)

The car is fitted with wilwood manual disc brakes. Will these rims fit and what's the widest I can go on rear? It has HD rear springs, looks like super stock. Can I go 275 60 or even 295 65?
Thanks...should have it in 1-2 wks if all goes well
 
Are the 72s any different than 70s? I mean, in the wheel wels? My 70 had a 255 60 15 on it, fenders were rolled and springs were moved over 1/2" with shackles. These were with a 4.25 BS, had about 2" clearance to springs, and 1/2" to quater panel. I just ordered 15X8 with 4.5 BS and 275 was the most I could fit comfortably.
 
72 What? 275/60 on a 15x8 is about the biggest you will get on a Duster with everything in Stock location.
 
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djais1801 said:
It's a 72 Demon w Wilwood manual discs
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275's are the biggest you're going to fit on a Demon with everything in the stock locations. The 15x8's are a piece of cake, no issues there. The ideal backspace depends on which rear axle you've got. If it's a 7.25 or 8.25 a 15x8 with a 4.5" backspace is good. If it's an 8 3/4 it's different, for a SBP set up 4.5" would be ok, 4.75" would work. If it's an 8 3/4 with BBP axles I'd go all the way to 5" of backspace. But unless you move the springs, cut the quarters, or jack it up like a 4x4 275's are as big as you're going to go. I have 295's on 18x10's on my Duster, but that took a 1/2" spring offset and another 1/2" worth of quarter lip trimming.

Also, not all A-bodies have the same clearance. Dart's, Valiant's and Scamp's have about an inch less room than Duster's, Demon's, and Dart Sport's. And the pre '70 cars tend to be a little tighter than the post '70 cars. The only exception is the pre '70 valiant's. They have the same wheel tub as the Dart's, but they have a higher wheel opening so you can "cheat" a little, if your car isn't lowered significantly you can get away with hanging the tires out a little further than on a Dart.
 
72bluNblu said:
275's are the biggest you're going to fit on a Demon with everything in the stock locations. The 15x8's are a piece of cake, no issues there. The ideal backspace depends on which rear axle you've got. If it's a 7.25 or 8.25 a 15x8 with a 4.5" backspace is good. If it's an 8 3/4 it's different, for a SBP set up 4.5" would be ok, 4.75" would work. If it's an 8 3/4 with BBP axles I'd go all the way to 5" of backspace. But unless you move the springs, cut the quarters, or jack it up like a 4x4 275's are as big as you're going to go. I have 295's on 18x10's on my Duster, but that took a 1/2" spring offset and another 1/2" worth of quarter lip trimming.

Also, not all A-bodies have the same clearance. Dart's, Valiant's and Scamp's have about an inch less room than Duster's, Demon's, and Dart Sport's. And the pre '70 cars tend to be a little tighter than the post '70 cars. The only exception is the pre '70 valiant's. They have the same wheel tub as the Dart's, but they have a higher wheel opening so you can "cheat" a little, if your car isn't lowered significantly you can get away with hanging the tires out a little further than on a Dart.
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it has 8.75 rear with LBP. so i'll be good with 4.5BS on a 275 60?
 
djais1801 said:
it has 8.75 rear with LBP. so i'll be good with 4.5BS on a 275 60?
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you really need to get out there and do some measurements on your own car. that way you know that wheel/tire combination is going to work on your specific car
 
djais1801 said:
it has 8.75 rear with LBP. so i'll be good with 4.5BS on a 275 60?
Click to expand...

Not really. You might get away with 275's on 15x8's with a 4.5" backspace because of the super stock springs, but it's because of the ride height not because the tires will fit in the wheel tubs. Doing the math compared to my Duster that wheel package will have .1" more clearance to the quarters than mine. But that's not enough if you have stock quarter lips, I cut over a 1/2" from the quarter lips on my car to keep my tires from rubbing and I only have about a 1/2" of clearance now.

***Edit***
I forgot about the disks, if you have disks in the back you lost another 1/4" or so of clearance because rear disk kits increase the track width. That number varies with the kit, but a 1/4" wider per side is common.
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So, unless you cut the quarter lips back you won't have enough clearance to actually fit the tires into the tubs. So they won't work on a car at stock or lower ride height. Now, if the car rides high in the back and the rear suspension is stiff (like you'd get with SS springs) then it will probably work, the quarter lips will probably be high enough above the section width and lots of people hang the tires out of the wheel openings on Dusters. Really though, with a BBP 8 3/4 A-body rear and 15x8's you should have more like 4.75" to 5" of backspace if you want 275's to actually fit into the wheel tubs.

UDUST81 said:
you really need to get out there and do some measurements on your own car. that way you know that wheel/tire combination is going to work on your specific car
Click to expand...

And this of course is always good advice, especially if you're trying to cram the biggest wheel possible in there. The body tolerances on these cars weren't that great from the factory, so, just because it fits on another car doesn't always mean it will fit on yours. Generally speaking 275's on a Duster are a fairly safe bet, but I'm sure there are still a few exceptions out there.
 
I just edited my post, I forgot you mentioned the wilwood disks. Does it have disks in the back?
 
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