67 Dart Rear tires

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HemiD@rt

HemiD@rt

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Ok guys I need to know if I can stuff a 275/40/18 in the rear well? I know I will have to get the leaf relocation brackets, but will the wheel well hold that wide of a tire? It is going on a 9.5" wheel with 5" BS.

Thanks!
 
a 255/40/18 fits in stock wheel well ,rim size is 8 inch wide 4.5 back spacing.no wheel lip rolling done yet and there is clearance.So I would say with that back spacing and a lip roll it would be real close but possible.
 
Largest I've heard without tubbing or spring relocation was a 275/40/17... However, trimming and rolling lips were involved. So maybe bump the tire down to a 275/35/18 to make it work.
 
hemidart67 said:
Going to a 275/35/18 only changes the tire height not width
Click to expand...

Right, but with the proper backspacing and trimming you'd be able to fit it in. From what I know a 275/40/18 would be too tall and start hitting the tubs. That's almost a 27" tall and 11" wide vs being a little less than 26" tall.
 
I put a 275/40/17 on my '71 Dart with a 17x9 with 5" backspace. The tire made contact with the quarter lip and the springs, but sat in place. A 1/2" spring relocation and a rolled/trimmed quarter lip should make it possible, as long as your rear axle is actually centered in the car.

The only concern I have is the 9.5" wheel and 5" backspacing. With a 9.5" I'd want at least a 5.3" backspace, but really 5.5 or 5.6" would be better. You can always run small spacer if you get too close to the springs. An 18x9.5" with 5" backspace and a 275/35/18 will sit an extra 1/4" further out than mine were, and that will all have to come out of the quarter lip and then some for clearance.

Ideally, with a 9" rim and a 1/2" spring offset, I'd want 5.25" bs, which should be about 1/4" clearance on the springs and the quarter lip with a 275, with extra clearance to be had on the outside from trimming the quarter lip. With a 9.5" wide rim, that's 5.5" of backspace.
 
height will depend on stance. 26-27". But 10.50 is about max on the real estate with OFFSET springs.
 
What is offset vs backspace?

The wheels I'm looking at have -4 offset and 5.03 backspace
 
Backspace is the distance from the wheel mounting surface to the inside lip of the rim. Offset is the distance between the wheel mounting surface to center, and can be positive or negative. Just two different ways to reference the geometry of the rim.

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5.03" of backspace won't be enough on a 9.5" wide rim. With the offset springs and a 9.5" wide wheel I'd be looking for at least 5.5" of backspace. Remember, you can go with more backspacing and run a spacer, but if you go with less backspace and your tires hit the quarter the only thing you can do is shorten the axle. Or buy new rims with more backspace...
 
Ok I have 2 other options. 8" wheel with 14 offset and 4.99 BS

Or 8" wheel with 2 offset and 4.52 BS

Would one of these be better for my rear?
 
HemiD@rt said:
Ok I have 2 other options. 8" wheel with 14 offset and 4.99 BS

Or 8" wheel with 2 offset and 4.52 BS

Would one of these be better for my rear?
Click to expand...

With an 8" rim the widest you'll be able to run in an 18" wheel is a 255/40/18, and even that's pushing it, smallest recommended for a 255 is a 8.5" wide rim.

The good news is that a 8" rim and 4.99" backspace would fit fine, even without a spring relocation.
 
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