Converting Your Imperial's 14 inch Hubcaps to Fit on 15 inch Wheel Rims

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This article was copied from the 300 Club's website with permission from the club and the author.  There are many informative, technical articles on their site and we recommend that you visit them for additional information.


Also, read Dan and John's articles on how they converted their drum brakes to disc brakes.


Try as I might, I just could not figure out a way to position calipers and rotors to fit inside of the 14" wheels of my 300F without changing out the entire spindle system, which I did not want to do. Also, I wanted to maintain the same or approximate tire diameter so as not to change the speedometer and odometer readings any more than they are now.

Therefore, I decided on 15" wheels to accommodate the discs. Also, I did not want to give up the beautiful F wheel covers. Thus, the necessity to modify 15" wheels to take the 14" wheel covers. 

Here is how I did it:

I have learned that Stockton Wheel would convert my wheels for $175 each. They confirmed this to me at their vending spot at Spring Fling. They would supply the 15" wheels and the buyer would supply the 14" donor wheels. I would assume that all shipping costs would be borne by the buyer. I believed then that I could do it at less cost.
With the project complete, I know that my total cost for doing 5 wheels is $158.16. A breakdown is as follows. Of course someone else doing the same project may have higher or lower costs depending upon whether they had to buy wheels, had someone else do the cutting or did the welding by themselves, etc. I had no wheels and had to hire out the welding but I did do the cutting and shaping of the donor rims myself.

Wheels:  $85.56
Jig saw blades:  $22.60
Welding:  $50.00
Paint:  Free
Total Cost $158.16

It is a relatively easy project. If you do it yourself, it will require about 1 to 3 hours per wheel to cut and prepare the rims from the donor 14" wheels, depending upon the method you use to cut off the donor rims. You may innovate and find a quicker method such as a plasma arc cutter. I first armed myself with a very good quality hand jig saw (Skil) and a goodly supply of blades. As it turned out, I went through about 15 bi-metal blades. So here is how the project goes.

Step 1. Obtain five 15" wheels and three 14" donor wheels. Since there are two rims on each wheel, you only need three donor wheels. It also allows for an extra rim in case you screw one up.

Step 2. Mark the lines for cutting as shown in Figure 1. Using a jig saw or if someone has a plasma arc cutter, cut out the donor rims. I prefer the jig saw method, although it is more time consuming, as I wanted to take no chances of warping the donor rims.
Step 3. After removing the donor rims, grind the rough edges and cut and file smooth a V notch for the valve stem to protrude through. I suggest you insert a valve stem in one of the 15" wheels and place the donor rim in its place to make sure that you have enough clearance. Make sure you grind off any small curve remaining on the outer circumference of the rim as shown in Figure 2 as you want the surface of the donor rim to fit snugly against the wooden jig to be covered later. Since the outer edge of the rim will be welded to the 15" rim, I decided to cut drain holes in the outer circumference of each donor rim. Actually, I cut 16 of them, each about 1" wide using the grindstone to cut the holes at 22.5 degree intervals. Welding was to be done at the edges between the drains.

                        A view of a cut off rim from the outer side.                                                   

                                 An inner view of the same rim.
A view of the 14" rim in the 15" wheel prior to welding.                               
Step 4. I then made a wooden jig to hold the donor rims in place while welding. This is a must, otherwise, the donor rim may be welded in crooked and the wheel cover may wobble as the wheel rotates. I made the jig using a %" piece of pressed wood for the donor rim and 3/8" for the 15" rim. The circumference has to be exactly the inside diameter of the donor rim and fit very snugly. This I accomplished by drilling a center hole and using a router with a circle making attachment. I fine tuned the radius downward until I got a snug fit. The same was done with the piece for the 15" rim. After both pieces were finished, a center pin was placed through both pieces and they were screwed together. I then cut notches out of the 3/8" piece at various intervals for tack welding and a larger notch in both pieces where the valve stem protrudes.
I made the wooden jig after cutting and grinding the rims. However, in looking back, I believe it would have been better to make the jig before doing the grinding to fit the donor rim into the 15" wheel. This way, you can place the donor rim into the jig and see how it fits into the 15" wheel. You can grind to fit accordingly. 1 simply eyeballed my work and luckily the rims came out fine.
Step 5. As seen in Figure 3 the donor rim was placed on the jig and held in place by 4 "L" brackets. In order for the 3/8" piece to fit into the 15" wheel properly, you may have to bevel the edge around the circumference nearest the wheel to make it fit the curve and lay snugly against the rim.
Step 6. After placing the jig and donor rim into the 15" rim, welding can now take place. I used 4 "C" clamps to ensure positive contact between the jig and 15" wheel. Make sure the notch for the valve stem is lined up properly. Actually, I suggest having a valve stem installed in each wheel to make sure it is centered in the notch. I selected the Heli arc welding process as it produces less heat and there is less chance of warpage. The rims were tack welded together at several locations and the jig removed. Welding was then finished. You only need to weld between the drain holes if you so choose to have them. After welding is finished, take a grinder and grind the weld beads flat to make an even surface between the 14" donor rims and the 15" rims. (See Figure 4)   If after grinding, you do not have a smooth surface, you may want to even it up using JB Weld as I did.
Perhaps cutting a wider part from the donor wheel would allow the donor rim to be welded on both sides but I decided to make it narrow and weld on one side only. However, there is adequate surface for the tangs of the wheel cover to engage and I left a portion of the curve behind it to help with rigidity.


Reverse side of the wooden jig I made to hold the rim in place for welding. Note the "L" brackets for securely holding the rim.
Front side of wooden jig. Notches were cut to allow for tack welding before removing jig.
Jig and 14" rim in position in 15" wheel. Four "C" clamps were used to maintain position while tack welding.
The welds were ground smooth, JB Weld was used for finishing the surface and then painted. This photo shows a close-up of the finished product. There are 16 slots equally spaced around the circumference to permit drainage. Don't be fooled by the weights. The rims balanced out perfectly prior to mounting the tires.


Step 7. Since there remains a cavity between the rims, I cleaned off the surfaces in this cavity of both rims prior to welding. After the welding was done, I taped over the drain holes and poured black rust resistant primer paint into the cavity and turned the wheel until all of the surfaces of the cavity were coated. I then drained the excess.

Step 8.  Prepare and paint the wheels

Step 9. Mount the tires on the rims and onto the car. Install the wheel covers. Please note here that if you do not elongate the hole in the wheel covers, the valve stems may bend inward very slightly. I chose not to modify the holes as I want to leave my wheel covers in original condition. Also, I used the long valve stems.

Step 10. Stand back and admire your handiwork


                          A view of the complete assembly.
                  Another view of the complete assembly.                  


Figure 1

Figure 2

Figure 3

Figure 4


This page last updated November 17, 2003.  Send us your feedback, and come join the Imperial Mailing List - Online Car Club