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Wheels, axle shortening, spring relocation questions

TT from NH

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I am now starting to add parts and pieces back to my 68 Coronet 500. I wanted to start with the rear wheels since I had lots of questions about my plan to begin with.

First off, I LOVE the slotted aluminum wheels since I had them on my 68 Coronet 500 in high school. I appreciate that you may not have this same love as I do, but please understand that this is a non-negotiable in this discussion :) And I want MEATS! The wider the better.

I had I picked up some 14” x 10" wheels in Carlisle a couple years and quickly decided those weren’t tall enough and all the cool kids were going with 15”. So I picked up a number (six total) 15” x 10” for the rear. One of the sets was a local purchase and had rubber on them.
1763898925732.gif


The thing is, all these old slotted wheels had only 3.5” backspacing … which means 6.5” is sticking out from the hub. Which means that all my mini-tubbing is for naught:
1763898811804.png
1763899107833.gif


I have three choices and want your opinion.

Option #1: Run what you brung. I could just leave things alone and mount what I have (I’d probably opt for taller tires which isn’t a big deal). Positives: easy, doesn’t suck too much. Negatives: sucks a little to have the tires sticking out a bit … especially with all that available real estate inboard.
1763899121733.gif


Option #2: I could try to find modern 10” wide slotted wheels with 4.5-6.5” backspacing (instead of the 3.5” on my current wheels). Problem is, I don’t think I’ll find any slotted wheels. I could try 16” or even 17” (lord knows there’s room), but I WANT THE SLOTS!
1763899144944.gif


Option #3: Narrow the rear end. This is a little like shrinking your head because you LOVE that bit-too-small baseball cap. In addition to purchasing a leaf spring relocation kit for $399, there’s some cutting of the frame to weld the kit pieces in place … which I’ve done before so that doesn’t worry me too much. However, I would also then need to cut a 3” (or so) section out of each side of the axle housing AND the axle itself. And that scares me a bit (at least the axle part since I assume I cut the three inches off the spline end that connects to the differential and I don’t think you can simply hack it off…)

1763899177061.gif


Thoughts?
 
MANY years ago I took an 8-3/4 in to Mosers. They narrowed the housing and shortened and resplined the axles for $100.. While the price has no doubt risen, this would be your best alternative.

Having mini tubbed my car to what appears the same width as yours I had Strange Dana 60 built. I could have got away with not narrowing it but since it was a custom build anyway there was no addidional cost to having it built the width I wanted. I only narrowed it by 1/2" per side - just to make sure my tires clear the wheel lips. I use 15x10 Welds with 5-/12 backspace. Tires are 28x12.5-15. Springs are moved inboard.
 
For just those 15x10's if you are set on what you have with that 3-1/2" back spacing. You will only need to narrow the axle to accommodate those wheels and depending on your tire size you may not have to relocate the springs inboard. I made some pucks that bolt onto the bolt pattern of the end of the axle housing with an 1-1/4" hole drilled in the center. I slide a solid 1-1/4" round bar stock I have through the center holes of each puck to keep everything aligned and true to keep the housing from warping from the heat and move all around while welding also to minimize the warping.
I did all 3 on one of my cars. Mini-tubbed, relocated the springs inboard and narrowed the Dana 60 to accommodate my 15x12 wheels and 315 Drag Radials.
 
I am now starting to add parts and pieces back to my 68 Coronet 500. I wanted to start with the rear wheels since I had lots of questions about my plan to begin with.

First off, I LOVE the slotted aluminum wheels since I had them on my 68 Coronet 500 in high school. I appreciate that you may not have this same love as I do, but please understand that this is a non-negotiable in this discussion :) And I want MEATS! The wider the better.

I had I picked up some 14” x 10" wheels in Carlisle a couple years and quickly decided those weren’t tall enough and all the cool kids were going with 15”. So I picked up a number (six total) 15” x 10” for the rear. One of the sets was a local purchase and had rubber on them.
View attachment 1952288

The thing is, all these old slotted wheels had only 3.5” backspacing … which means 6.5” is sticking out from the hub. Which means that all my mini-tubbing is for naught:
View attachment 1952287 View attachment 1952291

I have three choices and want your opinion.

Option #1: Run what you brung. I could just leave things alone and mount what I have (I’d probably opt for taller tires which isn’t a big deal). Positives: easy, doesn’t suck too much. Negatives: sucks a little to have the tires sticking out a bit … especially with all that available real estate inboard.
View attachment 1952292

Option #2: I could try to find modern 10” wide slotted wheels with 4.5-6.5” backspacing (instead of the 3.5” on my current wheels). Problem is, I don’t think I’ll find any slotted wheels. I could try 16” or even 17” (lord knows there’s room), but I WANT THE SLOTS!
View attachment 1952293

Option #3: Narrow the rear end. This is a little like shrinking your head because you LOVE that bit-too-small baseball cap. In addition to purchasing a leaf spring relocation kit for $399, there’s some cutting of the frame to weld the kit pieces in place … which I’ve done before so that doesn’t worry me too much. However, I would also then need to cut a 3” (or so) section out of each side of the axle housing AND the axle itself. And that scares me a bit (at least the axle part since I assume I cut the three inches off the spline end that connects to the differential and I don’t think you can simply hack it off…)

View attachment 1952294

Thoughts?
Yukon makes 8 3/4 axles with an extra-long spline on the end and after you narrow the housing you simply use an abrasive cut off saw and cut them to fit. Yukon axle kit for Chrysler 8.75 | YA C8.75-32.0-KIT | Yukon Gear & Axle
 
Thanks for your replies. I think I'll move forward with the spring relocation and housing shortening. I've watched a few videos and read a couple of articles and feel confident that I can do this. @Rebelrouser , I'll check out the axles.

Question: I'm considering AMD's leaf spring relocation kit for $399 (Leaf Spring Relocation Kit - 66-70 Dodge B-Body) Any thoughts/alternative suggestions?
 
I think it is a great look once done. Mine is an E Body but a medium tire on B Bodies look great also.

20240717_172121.jpg


20240914_095411.jpg
 
Update: I used the AMD spring relocation brackets to move the leaf springs inward 4". The instructions are a bit confusing for the novice so I made a video which I'll post someday. I then chopped 4" from each side of my axle housing inside the perches which effectively allowed me to keep the perches and the angle. I just ordered shortened axles from Dutchman. Here are some pics:

IMG_6575.jpeg
IMG_6785.jpeg
IMG_6796.jpeg

(I used the excess tubing to support my butt weld. Not pretty, but strong.)

Here is a before pic and after pic that shows the old and new wheel placement:
IMG_6352.jpg
IMG_6790.jpeg

I'm hoping to put Hoosiers that push my 10" rim; they seem to be the tallest tire I've seem to fill this tub. If anyone has any other suggestions, let me know.
 
If you went 4" in,board. You should be able to go with a 12" wide wheel. That is what I have. Depending on if you moved your inner wheel wells all the way to the frame rails or not. In your pictures above it looks like they may not be moved in as far as your springs have been moved.
 
Thanks @6PKRTSE. I was thinking of going with the Hoosier 31X12.50R15LT PRO STREET:
  • Tire Size: 31x12.50R-15LT
  • Appr. Rim Widths: 8.5-11"(10")
  • Overall Dia.: 30.5"
  • Section Width: 13.5"
  • Tread Width: 10.3"
The Hoosier 29X15.5RLT PRO STREET tires may be just too wide for my 10" rims (plus, I lose 1.5" diameter):
  • Tire Size: 29x15.50R-15LT
  • Appr. Rim Widths: 11-13"(12")
  • Overall Dia.: 29.0"
  • Section Width: 15.2"
  • Tread Width: 12.1"
 
Last edited:
First question. Do you have enough room to run a 30 1/2 tall tire?
I can run a 30, but only cause I moved the rearend back an inch.
Second. Do you want the extra height for gear ratio purposes, traction purposes, or just to fill the wheel well?
Third. Would you feel bad about the fat tire on only a ten inch rim?
Your answers to these will help you decide on the tire you want.
Personally, I would opt for the wider shorter tires if they'll fit in the space you have, and the gear ratio you have will work. That much work calls for a BIG tire, at least to me.......



For what its worth, I have 18x31 Hoosier quick time pro's on one of my cars. (On slightly too narrow rims)
 
Thanks @6PKRTSE. I was thinking of going with the Hoosier 31X12.50R15LT PRO STREET:
  • Tire Size: 31x12.50R-15LT
  • Appr. Rim Widths: 8.5-11"(10")
  • Overall Dia.: 30.5"
  • Section Width: 13.5"
  • Tread Width: 10.3"
The Hoosier 29X15.5RLT PRO STREET tires may be just too wide for my 10" rims (plus, I lose 1.5" diameter):
  • Tire Size: 29x15.50R-15LT
  • Appr. Rim Widths: 11-13"(12")
  • Overall Dia.: 29.0"
  • Section Width: 15.2"
  • Tread Width: 12.1"
Thanks @6PKRTSE. I was thinking of going with the Hoosier 31X12.50R15LT PRO STREET:
  • Tire Size: 31x12.50R-15LT
  • Appr. Rim Widths: 8.5-11"(10")
  • Overall Dia.: 30.5"
  • Section Width: 13.5"
  • Tread Width: 10.3"
The Hoosier 29X15.5RLT PRO STREET tires may be just too wide for my 10" rims (plus, I lose 1.5" diameter):
  • Tire Size: 29x15.50R-15LT
  • Appr. Rim Widths: 11-13"(12")
  • Overall Dia.: 29.0"
  • Section Width: 15.2"
  • Tread Width: 12.1"
A 31" tire you may have to space or move the axle back some or radius/stretch the wheel well openings.

I used to run 32x14 slicks and 31x16.5 Hoosier street tires on my 69 Charger with a mini tub and I had to metal work the front of the wheel well lip openings to clear the tires.
 
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