At an impasse with rear wheel/tire fitment

[TylerW]

Hey guys:


I just finished installing new rear springs and shocks on my '73 Dart Sport with it's original 7.25 rear.

When I installed my wheels and tires, I found the front inside of the tire rubs the leaf springs. They are 255/60/15 tires on 15x8 rallyes with 4.5" backspacing.

So, what are the options here?

1. Same tires on 15x7 with 4.25 bs(that's the only other size 15" rallye that would look good on the rear that I'm aware of)

2. Less tire on the same rim.

3. Spacers( I installed 5/16 spacer and it clears the spring, but not enough stud length. I know everyone SAYS they had plenty left but there is NOT). Not crazy about spending time and effort installing longer studs on that temporary rear.

I can't spend the amount of money required for two new tires or two new wheels to make a guess, so SOLID recommendations are a big help. Not sure why there is so much variance between vehicles anyway..some people have my size combo and it fits, some like me have it and it doesn't come close.

Thank you.

 

[72bluNblu]

The 7.25 rear is likely to blame. They're actually narrower than an A-body 8 3/4", the 7.25 in my '74 Duster was narrower by about an inch. So yeah, a 15x8 with 4.5" backspace will fit an A body with an A-body 8 3/4" and the stock spring location. All of the axle charts/guides say that the A body 8 3/4 and 7.25 are the same width, but they're not.

I would install longer studs and use a spacer. I used Mr. Gasket #4311 studs on my stock 8 3/4" axles. http://www.summitracing.com/parts/mrg-4311

Maybe it's not an afternoon you want to spend pulling the axles and changing the studs, but its by far the least expensive way to go. And if you are planning on swapping an A-body 8 3/4" in later your rims and tires will be set up correctly for it.

 

[BigBlockMopar]

Installing longer studs would be a 10 minute job, especially if the axle is for temp use only.
Knock back the orig. studs with a hammer, either or not with a piece of wood in between to save them for later use and pull in the new studs with some spare wheelnuts.

You could also try loosening the rearaxle U-bolts slightly with the car supported and see if you can pry/move the axle on the leafsprings a bit to gain just the clearance you need.

 

[cdavis]

Installing longer studs would be a 10 minute job, especially if the axle is for temp use only.
Knock back the orig. studs with a hammer, either or not with a piece of wood in between to save them for later use and pull in the new studs with some spare wheelnuts.

^^This. There is no need to pull the axles to replace the studs.

 

[2 Darts]

Hi Tyler,

Used to live a few miles away, spent a lot of time skiing on the lake. One of the South's best kept secrets IMO.

I have two Darts, a 72 Demon and a 73 Dart Custom. Both have BBP disk brakes, front anti-roll bars, 7¼ BBP rear axles, and 15 x 7 (4¼" BS) (Cop car, Magnum 500s).

I tried 255/60-15 on the cop car wheels on the Demon. Rear tire was ¼" from spring. Front tire would not fit under fender. I called Stockton Wheel and asked for recommendations. They advised 235/60-15 which is snug but workable. It bottoms out in the fender up front on turns. The next time I get tires for this car, I'm going to go to 225/60-15.

The Dart Custom has 205/60-15. I set up the front end following the recommendations of AutoXCuda. Powered by a /6, the car is the epitome of a momentum machine. The tires do not rub anywhere. I had some concern that the smaller tire on the Dart might look a bit dorky. Form your own opinion.

 

[72bluNblu]

I tried 255/60-15 on the cop car wheels on the Demon. Rear tire was ¼" from spring. Front tire would not fit under fender. I called Stockton Wheel and asked for recommendations. They advised 235/60-15 which is snug but workable. It bottoms out in the fender up front on turns. The next time I get tires for this car, I'm going to go to 225/60-15.

The cop car rims are 15x7 with a 4.25" backspace if they're originals. That's what I had on my Duster, with 225/60/15's all the way around. Even with the 225's I didn't have a ton of room to the rear springs, the BBP 7.25's are only like 51.5" flange to flange compared to the 8 3/4's which are supposed to be 52 5/8".

The 225/60/15's fit just fine up front, I didn't have any interference issues with those, although they do still sit fairly close to the fender. On the Duster I used the front fender-to-bumper braces to move the lower outer corners of the fenders out, but that's not a problem on a Dart because the wheel opening angles forward. That tire combination was actually how I set up the backspacing on my 18x9's with 275/35/18's, the outer face of the 275's is in the same place as the 225's were.

 

[TylerW]

Thanks guys, you are all a wealth of info. I will go the spacer and stud route for now. The 8-3/4 is present and accounted for, but still in the building stage.

I might add that this car I am building has been off the road in a Texas field for 20 years, so I'm finding each and EVERY thing that doesn't fit just right or match or things like that

2 Darts, nice to meet you. Guntersville Lake is becoming more well-known now with the tournaments that go on as often. I like that car!

74blunblue, I've been following the build on the '74 Duster. Really has inspired me to keep going on my own car.

 

[TylerW]

^^This. There is no need to pull the axles to replace the studs.

Quick question:

Where would I be able to find a set (10) of longer studs that won't break the bank?

This is a 7-1/4 with 1/2" studs.

Thanks.

 

[moparlover]

1/2" spring relocation kit (dr diff has them pretty reasonalby priced) moves the springs in 1/2" or even 3/4"

 

[72bluNblu]

Quick question:

Where would I be able to find a set (10) of longer studs that won't break the bank?

This is a 7-1/4 with 1/2" studs.

Thanks.

Since you've got a BBP, 1/2 stud set up I bet the #4311 Mr. Gasket studs would work for you. I know its a 7 1/4, but since it uses the larger diameter studs I'd bet they used the same ones as the 8 3/4.

1/2" spring relocation kit (dr diff has them pretty reasonalby priced) moves the springs in 1/2" or even 3/4"

Both the Mopar and Dr. Diff kits only move the springs in 1/2". Mopar claims 3.4", but I measured them, they're only a 1/2" different from stock. That route also requires welding on new perches, and since the 7.25" in question is "temporary" it would be much easier just to replace the studs.