A Jig To Increase Rim Backspacing: Recentering

I have 3/4 ton full width axles (69" wms front, 67" wms rear) and would like to narrow the track width a little. I would like to recenter my rims to increase backspacing. I've read somewhere that it might be less of a hassle to just buy new rims with custom backspacing. I've also read that getting the centers positioned in their new location must be done precisely with a shop set up otherwise I will end up with a wobbly wheel. I want to see if I can make this work with the rims I already have and parts I can piece together. If I ruin these, then that's when I'll buy new rims with the proper backspacing.

I'm thinking of making a simple jig for recentering.

Here's an exploded drawing:


The idea is to grind all the welds attaching the rim center to the rim. The nut on the left side of the drawing is against a washer that is against a thick steel plate. The diameter of the steel plate will match the wheel mounting surface. The steel plate will be the part applying pressure to the rim center. Bolts and lug nuts (lug nuts not shown) will be used to keep the steel plate and the rim center together. A long threaded rod will thread through the nut and pass through the washer and the round steel plate to another round steel plate (right side of the drawing). The bigger steel plate will fit snugly on the rims lip (the support)...a nut (not shown) will be welded at the center hole of the bigger steel plate. The end of the threaded rod will be ground to accept a socket. The idea is when the threaded rod is turned, the two plates will move toward each other...since the rim center will have the welds removed (and just pressed in) and the larger plate is pushing against and being held in place by the rim's lip, the rim center will move.

one problem I see is that the plate on the right side of the drawing, the one against the lip of the rim, might spin...

what do you guys think?

 

I had a 1962 F-500 truck some years ago that I removed the duals off of and re-centered two extra rims to track with the front so I could run a single, These older 20" rims had rivets but the concept is the same.........After I ground the rivets off I repositioned the center with a block of wood and a big hammer to the back-set I wanted then put the assembly back on the hub being careful not to rotate the rim from its original location on the center..........I then had a friend rotate the axle by turning the rear wheel on the other side while I was holding a tape measure against the frame and gently tapped here and there until the rim ran true..............Tack welded in three places and rechecked for true. Finished welding it with a series of evenly spaced 1 1/2 inch long beads ( bead - space - bead - space ).
They ran straight and true with no wobble or other problems.

 

p.s. you didn't think I can play with mspaint?

 

p.p.s.; a little Paint here, a little Paint there.

 

I was trying to avoid using the BFH and make something that evenly presses the center instead. I guess it's not that delicate.

 

Library books? Now I have to keep my librarian wife away from this site or she'll be after you. R)R)

And can't top the FBH, although out here we call them BFH. R)

 

this block of wood sounds very simple. I would just cut the block to the right height and stand it on a flat surface. then put the rim sideways over the block so that the center is resting on the top of the block. I can put a 2x or 4x across the top lip of the rim to spread the hammer's blow until the rim bottoms out...it's cheap too.

 

When I did this I was not to concerned about damaging the heavy 20 inch steel truck rims. I only had two of them to do so any time spent doing it caveman style with simple tools was not a concern.
All kidding aside I just laid the rim flat in the dirt and used the block of wood to soften the hammer blow as I worked my way around the center in a circle adjacent to the rim untill I had it close to where I wanted it.
Once it broke loose from its original position it moved quite easily and thats when I put it back on the hub and finished tapping it straight the last 1/4 inch while my helper turned the tire on other side.
The unglamorous truth be told I just laid it flat in the dirt and beat it into submission with a block of 2*4 and a 4 pound hammer :twisted:

 

So instead of the fancy 3D puller I was thinking about...I took everyone's advice and just BFH'd it...
one rim done...took about 3 hours

 

Looks good from here All kidding aside the weld beads look good nice job.

 

I just finished moving the center on the 2nd rim and I think i'm gonna switch the wire to flux core. I'm using a 110 machine so I might have to get those welds chased later...