My coaster brake wheel (swap meet bargain) was getting a bit wobbly with its banged up rim and the rag joint sprocket was making it more noticeable. Also, my coaster brake wheel is 26 X1 3/8”, so I can only run that one narrow tire size (Mountain bike tires like 26 X 2 don’t fit). (see 1st pic). Too bad because it had a strong Shimano coaster brake.
I pulled a rear disk wheel (another swap meet bargain) from my inventory.
A disk mount sprocket from Kings soon arrived in my mail box. During the first install attempt, it became quite obvious that there were clearance issues with my circa 1976 beach cruiser frame and the disk mounted sprocket. (I doubt there would have been clearance issues with a contemporary mountain bike frame). The sprocket rubbed the seat stay of my old US made cruiser.
By the following weekend, I decided to trim about 3/16” from the face of the disk mounts to allow proper clearance. I brought the disk hub into my personal machine shop (consists of a hack saw, rasp and a Dremel) for mods. I was able to trim the disk mount without reducing the depth of the bearing cup.
Fresh from my personal machine shop, I mounted the wheel, connected the motor chain, single speed cog and spacers in place of the gear cluster, and pedal chain. The first test ride showed that the skewer axle wasn’t adequate. I pulled a solid axle & associated parts from one of my old rear derailleur wheels (it had four busted spokes) and installed it on the new disk wheel.
I am very happy with the results. The chain and rear wheel are very smooth. I am able to run a larger 26 x 1.75” tire on the rear. The expense and effort was worth it.