315/60R15 vs 295/50R15 Rear End Length for Dart Sport

[Kevindc]

I'm currently working on the measurements for the rear end for my 73 Dart Sport and would like some opinions on the following. The car is mini tubbed with the springs moved to the rails. I already have MT 315/60R15's mounted on Cragar SS rims. The problem is that the wheel diameter is to great (30") to fit up into the fender wells without hitting the front and rear of the fender. I could run these but the back of the car will probably sit higher than I would like. Right now I have a inside rim to inside rim measurement of 52" (anyone know if this sounds reasonable?). If I want to get the wheels up into the fender wells it looks like I will need to go to a 295/50R15 tire. What I'm trying to figure out is if the 52" measurement will be good if I use either the 295 or the 315. I think it would be fine but I'm trying to make sure I don't miss something before I order the rear end. Thanks!

 

[fishy68]

Where the tires sit depends mostly on the back spacing of the wheels. The tires themselves have little to do where they sit other than their width. The 295/50/15 tires are only 10 mm narrower (3/8") but their height is only 26.6" so they should clear the front and rear openings of the fenders fine.

As for the axle flange to axle flange dimension, if it's a stock width A-body rear it should be 52-5/8" axle flange to axle flange

 

[Kevindc]

I'm learning as I go so this is where things are now. I began this by trying to go with the greatest diameter wheel I could find that was in the 315 range and would fit on a 15" rim. It just never occurred to me that the wheel wouldn't fit all the way up in the fender well. The distance between the front and back of the fender is about 30 1/4" and the tire is 30"+-. Then for some reason I got it in my head that there were no tires in the 315+ width that would fit in a 15" rim with an aspect ratio less than 60. Well I was laying in bed and thought wait a minute why did I think that. I ended up getting out of bed and pulled up some tire specs. This is what I found available:

BF Goodrich P295/50R15 Diameter 26.6"
Mickey Thompson P295/55R15 Diameter 27.8"
Mickey Thompson P325/50R15 Diameter 28"

It looks like any of these will work so I'm going to go with the MT P325/50R15. Concerning the rear end here is what I have figured out.

1973 Dodge Dart Sport
Mini-tubbed
Springs mounts moved to the rails (although I'm going with a 4-link)
Cragar SS Rims 15" x 10" with 4.5" Back Space

Inside Rim to Inside Rim 51-1/2"
Housing Width 46"
Spring Perches 36" On Center
Axle Flange to Axle Flange 51"
Disk Brake Width 1/4" Each

This rear end width should let me run any of the tires above. I ordered the rear end from Dr. Diff, a Strange S60, and if I remember I'll post when this is installed and let you know how it worked out.

 

[draginmopars]

this is on a 72 Dart Swinger

325x50-15
51" axle flange to axle flange
drum brakes
10" wheel
5" backspace

1" clearance at spring and outer wheel tub/lip