Drive Roller: Noob Help

I just finished my motorized bike (electric) recently, and the drive roller I used was a polyurethane skateboard wheel with the steel nut epoxied in with 2 part epoxy, the nut came with the motor (reversed threads).

Anyway the bike worked outstanding (20.2 mph tops). But sadly the epoxy started to give away and the wheel was barely hanging on.

So, I am just asking if someone can direct me to a site with well made (cheap) drive rollers, preferably metal with deep grooves so it won’t slip in wet conditions.

Here are the specks of my motor axel,
Total shaft length - 1" (back 1/2" circular, and front 1/2" reversed threaded w/ flat side)
Shaft diameter- 1/4"
Skateboard wheel diameter - 2 1/8"

***I cannot go any larger or smaller with the roller diameter… the motor is not adjustable.***(presure of the roller on the tire is just perfect)

Thanks

Well I guess a polyurethane wheel will work best then.

Does anyone know of a place online where I can get one on the cheap?
(2 1/8")

I wouldn’t ride this bike for that many miles, a polyurethane wheel is fine.
Does any one know where I can get one?

I need this rollerASAP
Anyone? please...

As you can see, I am desperate for this roller!!!!!!!!!!!!!1

Update:

I was trying to make another roller by melting the steel nut to the skateboard wheel... didn’t work too well. Something happened when I was trying to get the nut off the motor and the threads on the motor are totally mangled. So now my only options are to epoxy a roller to the motor permanently, or try to find a purpose built roller that has little set screws in it that clamp down on the axel,
look at attached picture, (this one is 1.5")