275/60/15 sidewall clearance to leaf spring clamps- suggestions?

[madhatta360]

Sup dudes-

slapped on a set of AR 15” wheels 4.5” BS I believe w/ 275/60/15. Running a 3/8” wheel spacer and still feel like it’s to close to comfort with the leaf spring clamps, removed them for now but need some solutions as I know they serve purpose with traction. My initial plan was to move them closer to axel by an inch or so not ideal but this will not be a drag car.

Springs are Mopar SS P4120863/64 looking to see if anyone ran into this running these tires on 73 Duster, 8 1/4” rear

Attached photos, maybe they are just this close for guys running them but to me seems dicey idk- looking for tips/suggestions etc.

 

[72bluNblu]

That’s without the spacer in the pictures?

Unfortunately you’ve discovered that the 8 1/4 is actually narrower than an A-body 8 3/4. The 4.5” of backspace on a 15x8” works well on an 8 3/4 with BBP axles, but with an 8 1/4 or 7 1/4 you need more like 4” of backspace.

You can move the clamps, but I think you’re stuck with the 3/8” spacers. Upgrade your wheels studs, run an high quality billet spacer and make sure you keep everything torqued.

 

[33IMP]

First, if you have the room to the fender, more spacer. Good quality long studs and a billet spacer. (No cast garbage).
Next, you could move the clamp closer to the axle, (your first thought)
You could also try to drill the leaves and use a bolt and nut in place of the clanp.

 

[madhatta360]

That’s without the spacer in the pictures?

Unfortunately you’ve discovered that the 8 1/4 is actually narrower than an A-body 8 3/4. The 4.5” of backspace on a 15x8” works well on an 8 3/4 with BBP axles, but with an 8 1/4 or 7 1/4 you need more like 4” of backspace.

You can move the clamps, but I think you’re stuck with the 3/8” spacers. Upgrade your wheels studs, run an high quality billet spacer and make sure you keep everything torqued.

Ahh yeah I think that’s why I ran into problems, should have just went with 255 but no needed an extra .8” haha

That pic is with the 3/8 billet spacers got good ones and found stud that are longer off of a jeep liberty they worked great actually so took care of alll that.

Might just have the spring shop down the road dial me in I don’t have anything to drill spring steel

 

[72bluNblu]

Ahh yeah I think that’s why I ran into problems, should have just went with 255 but no needed an extra .8” haha

That pic is with the 3/8 billet spacers got good ones and found stud that are longer off of a jeep liberty they worked great actually so took care of alll that.

Might just have the spring shop down the road dial me in I don’t have anything to drill spring steel

Those pictures are with the spacers?

Yikes. That’s still not enough space, especially with the clamps moved. You run the risk of one of the leaves shifting and cutting the tire.

Honestly I’d get a 1/2” spring offset kit from DoctorDiff and just have the spring perches moved. I personally wouldn’t want much more spacer than you already have, but you still need more clearance.

 

[toolmanmike]

Oops, That's why pretty much everyone on the planet runs 255's. I doubt very much if very many of us could tell you are running 275's. Not up close and damn sure not while you are driving by at 25. Sorry, No quick fix.

 

[madhatta360]

Oops, That's why pretty much everyone on the planet runs 255's. I doubt very much if very many of us could tell you are running 275's. Not up close and damn sure not while you are driving by at 25. Sorry, No quick fix.

Yeah I might just do the simpler fix and buy 2- 255’s and call it day vs all the other hoopla and extra work. My current tires still have sticker marks on tread and never cleaned white letters so basically new

 

[madhatta360]

Those pictures are with the spacers?

Yikes. That’s still not enough space, especially with the clamps moved. You run the risk of one of the leaves shifting and cutting the tire.

Honestly I’d get a 1/2” spring offset kit from DoctorDiff and just have the spring perches moved. I personally wouldn’t want much more spacer than you already have, but you still need more clearance.

I just looked up the dr diff not bad for the price seems easy to do- thought maybe you had to reweld to kick them in but the kit seems like straight bolt in

 

[72bluNblu]

Oops, That's why pretty much everyone on the planet runs 255's. I doubt very much if very many of us could tell you are running 275's. Not up close and damn sure not while you are driving by at 25. Sorry, No quick fix.

Actually a lot of people run 275’s on Dusters/Demons/Dart Sports. With the right backspacing they work fine on most cars in those bodystyles.

Problem here is the 4.5” backspace is what you need for an A-body 8 3/4 with BBP axles, which is too much backspace for the narrower 8.25”

I just looked up the dr diff not bad for the price seems easy to do- thought maybe you had to reweld to kick them in but the kit seems like straight bolt in

The hangers and shackles bolt on. The leaf spring perches have to be cut off and new ones welded onto the axle housing at 42” c-c (stock is 43”).

 

[toolmanmike]

Actually a lot of people run 275’s on Dusters/Demons/Dart Sports. With the right backspacing they work fine on most cars in those bodystyles.

Problem here is the 4.5” backspace is what you need for an A-body 8 3/4 with BBP axles, which is too much backspace for the narrower 8.25”

Correct you are. I wasn't paying close enough attention to what the op was driving. I'm always in Dart mode.

 

[madhatta360]

Those pictures are with the spacers?

Yikes. That’s still not enough space, especially with the clamps moved. You run the risk of one of the leaves shifting and cutting the tire.

Honestly I’d get a 1/2” spring offset kit from DoctorDiff and just have the spring perches moved. I personally wouldn’t want much more spacer than you already have, but you still need more clearance.

Those pictures are with the spacers?

Yikes. That’s still not enough space, especially with the clamps moved. You run the risk of one of the leaves shifting and cutting the tire.

Honestly I’d get a 1/2” spring offset kit from DoctorDiff and just have the spring perches moved. I personally wouldn’t want much more spacer than you already have, but you still need more clearance.

question for you- did doctor Diff make your kit to order? Went on website but was not available out of stock, sent email to them just curious

 

[madhatta360]

Doctor Diff the only option for bolt on spring relocation kits with exception to moving in the spring perches? Website out of stock looking for other recommendations that don’t require welding to frame etc got enough going on with this project already thanks

 

[72bluNblu]

Mopar performance used to make a kit too, they advertise it as a 3/4” offset but the front hangers are only offset a 1/2”. They’re a little harder to install because the hanger isn’t as nicely designed as the DoctorDiff ones

DoctorDiff usually gets his in stock a couple times a year, you might ask when he’s due for his next batch

 

[go-fish]

I run a 255 on my 8.25” equipped Duster. I still have to run a small spacer.
I would advise you to get 255’s now but save your 275’s. It sounds like you will be driving on these a lot so your new 275’s should keep.
Get on the waitlist in the meantime.

Click here:

Fill out your info and have them installed before you need tires again.

 

[madhatta360]

I run a 255 on my 8.25” equipped Duster. I still have to run a small spacer.
I would advise you to get 255’s now but save your 275’s. It sounds like you will be driving on these a lot so your new 275’s should keep.
Get on the waitlist in the meantime.

Click here:
View attachment 1716199451

Fill out your info and have them installed before you need tires again.


View attachment 1716199452

That’s my game plan sounds like I’ll be waiting for a bit for the set so I’ll just go with some new BFGoodrich 255’s until I can get the parts to do swap

 

[340six]

Looks like you have it figured out. But wanted to point out.
When you take the 275-60r15 off that are on 15x8 with 4.5 inch back space. And put the 275-60r15 on 15x8 with 4.25 back space you moved them to the quarter panel not sure how that plays in, my cars tight, real tight
I removed my 1973 Dart Sport 340 8 1/4 321:1 suregrip.
And installed a 8 3/4 Moser BB axle with green bearings, 11" drum brakes ( Sea Body, Van, Truck ones)
I am at max at wheel lips and close to springs.

 

[65 Cuda 340]

How much clearance now with the rear wheel opening lip? Seems to me like it would be easier just to buy a set of wheels with less backspace, and cheaper in the long run than buying a pair of 255's and also buying and installing an offset rear spring kit.

Edit, just checked my file because I couldn't remember what my backspace was, but I'm running 275/60-15s on the rear of my 67 Barracuda, 15x8 Cragars SS wheels, backspacing is 4.25. 8 3/4 rear, instead of your 8 1/4, so not directly applicable, but it clears OEM springs and fender lip nicely.

 

[33IMP]

For what little it's worth....
I ran 1/2" thick billet spacers I made on my 9 second racecar with no problems whatever. With a spool and 14x32 slicks, and 1/2x3" Axle studs.

 

[RustyRatRod]

Don't forget there are other options. lol

 

[dvw]

I've run 3/8" spacers on my racecar. Been 1.24 60ft. Good studs properly torqued is no issue. The stud doesn't drive the wheel. Clamp load between the rotor/drum and the wheel takes the load.
Doug

 

[madhatta360]

Got the doctor diff kit, dropped rear out welded up the perches and decided to paint the rear while it’s out.

Def will have plenty of side wall/leaf spring cleareance now for the 275/60/15 on 15x8 4.5” BS on 8 1/4”. Rear is going in this weekend and frame ties going on. Now will be ready for the road finally

 

[RustyRatRod]

Just my personal opinion. I don't like spacers, adapters, or anything that fits between the wheel and hub. Nothing but wheel. If you're having fitment issues, I urge you to get the correct backspacing.

 

[ajarofclay]

I just happened to be searching spacers and came across this thread. I have a similar situation but I'm running an 8.75 that was originally a B body rearend. I had it narrowed but in my haste didn't account for the 11 inch breaks. I made the adjustment with my aftermarket Rallye's using a 4" backspace. I have 1/8" clearance on my springs using 275's but for some reason the clearance on the right side at the front of the spring is only a sliver so I'm looking for a minimal spacer. The issue there is (as someone already mentioned) the outside gets closer to the wheel well lip. It should be fine but could be an issue if you hit a good dip in the road. This brings me to another point, primarily for you, #RustyRatRod... Is that your Duster (PRETTY)? If so, How did you attain that ride height in the Rear. I dumped my air shocks and even though these cars tend to set a little low in the rear, mine seems to sag more than it should, especially considering the rear tires are over an inch taller than the fronts. Looking for options besides air shocks again. Have new Monroes on there now.

 

[QuickDart360]

I just happened to be searching spacers and came across this thread. I have a similar situation but I'm running an 8.75 that was originally a B body rearend. I had it narrowed but in my haste didn't account for the 11 inch breaks. I made the adjustment with my aftermarket Rallye's using a 4" backspace. I have 1/8" clearance on my springs using 275's but for some reason the clearance on the right side at the front of the spring is only a sliver so I'm looking for a minimal spacer. The issue there is (as someone already mentioned) the outside gets closer to the wheel well lip. It should be fine but could be an issue if you hit a good dip in the road. This brings me to another point, primarily for you, #RustyRatRod... Is that your Duster (PRETTY)? If so, How did you attain that ride height in the Rear. I dumped my air shocks and even though these cars tend to set a little low in the rear, mine seems to sag more than it should, especially considering the rear tires are over an inch taller than the fronts. Looking for options besides air shocks again. Have new Monroes on there now.

View attachment 1716237524

The back rally are 8"? If I may ask who's wheel brand? From which company did u buy? I'm interested in getting some. Thank you.

 

[ajarofclay]

The back rally are 8"? If I may ask who's wheel brand? From which company did u buy? I'm interested in getting some. Thank you.

Hey Quick... I went with US Wheel and was very impressed and happy with them. I had read about issues with Wheel Vintiques (though, I had no personal bad experience) so I leaned toward US Wheel. I literally had gone back and force with them in emails for a couple of years, then eventually bought them from Jegs. After my mistake of forgetting the 11" inch brakes, the base wheels would have brought the tires against the wheel well lip so I went back to US Wheel with my query and was told that they do custom offsets. When I told them what I needed, he said that's another size they carry so he had me just contact Jegs and we did an even exchange. Great service and communication.