Is anyone out there running 15X8 (4.25backspace) Cragar SS on the back end of there Duster or Dart Sports, if so, any issues? I'm converting my a-body 8 3/4 from sbp to lbp and will be switching to 10X2 1/2 brakes. Looks like the change will push the wheels out by about 1/4" each side. I'm trying to determine if the 15X8 SS's with 4 1/4 backspacing will work with this combination. Besides the swap to lbp with brakes and axles the remainder of the housing is stock.
15X8 Cragar backspace ??
- Thread starter Duster_71
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Depends on your tire size.
With an A-body 8 3/4 that has BBP axles and brakes, and the stock spring locations, you typically want a 15x8 that has about 4.5" of backspace to max out your tire size. With a 4.25” backspace you’re losing a 1/4" to the quarter.
So, you probably won’t be able to run a 275/60/15 without getting into the quarter lip, unless your cars ride height is pretty high in the back. But a 255/60/15 would probably still work. Just depends on what tires you want to run.
With an A-body 8 3/4 that has BBP axles and brakes, and the stock spring locations, you typically want a 15x8 that has about 4.5" of backspace to max out your tire size. With a 4.25” backspace you’re losing a 1/4" to the quarter.
So, you probably won’t be able to run a 275/60/15 without getting into the quarter lip, unless your cars ride height is pretty high in the back. But a 255/60/15 would probably still work. Just depends on what tires you want to run.
RPMagoo
Just An Old Motorhead
-- Based on My calculations, on My 70 Duster, that will work. (8-3/4" rear - LBP) -- I'm in Florida, and heading back to Pa. the first week of March. -- I have a new set of 15" X 8" Cragars, with 4-1/4" BS, up there, and plan to install them with 255/60-15" tires, soon after I get home. Currently My rear wheels are 15" X 8" with 2" BS, and rub the lips. --
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Thanks 72bluNblu, I will be running 255/60/15's on the back. My car has a fairly high stance so that shouldn't be a factor. Plus I was running 15X8 sbp Cragar SS that have 4 1/8 -1/4 backspace, need to get a better measurement on them. Just don't want to go through the swap and end up with wheels that wouldn't work. Kinda like check, re-check and drive myself crazy, LOL.
Thanks Backally, Did you replace your brake lines when you made the switch to LBB, if so, did you get preformed or just bend your own?
Thanks, did you just order a-body 8 3/4 lines or was there a difference or special order for the brake backplate offset or did you go to disc?
It’s been a couple years but I think I got the standard 8 3/4 line. Seems there are two versions. They sent me a two piece line which was incorrect, I needed a single line from the proportion valve back. Other than that I don’t recall any issues. I got the 10x2.5 drums
Dusterguy21
New Member
Dusterguy21
New Member
RPMagoo what were the size and backspace of your front wheels and tire size the setup in the rear with the 15x8 2” backspace looks super good wondering if it’s worth the rub
On my 70 Duster with a stock 8 3/4 rear and BBP axles from Cass. I am running 255/60's on the back with steel wheels. I ordered a set of 15x8 with 5 inch backspace to get the wheels centered in the opening. 4.25" bs would have been really tight to the quarter lip. I am running stock height 6/6 340 leaf springs from ESPO as well.
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