To oil this wheel bearing, it is not necessary to remove the wheel.......just drop a couple of drops of a good light weight oil on the screw holding it on and rotate the wheel so the oil will get down to the bearing.
It uses 10mm x 330mm belts available at Campbell-Hausfeld dealers. I buy either 80 grit or 120 grit. I have 4 bench grinders, several air disc grinders, and sanders. I use this one very often and I highly recommend it.
Changing the belts can damage the arm supporting the front wheel if you push it hard sideways while loosening the setscrew to replace the belt. I use these steps:
1) grasp the arm with one hand and loosen the screw with the correct size of screwdriver. Do not hold it by the aluminum handle/housing.
2) push down on the wheel towards the handle, collapsing the tension spring, then tighten the screw.
3) replace the belt. The arrow on top of belt should point forward
4) loosen the setscrew, allowing spring to tighten the belt, then tighten set screw securely but do not over tighten
5) if belt rides to the side of front wheel, you can tweak the arm by bending it very slightly one way or the other until the belt rides in the middle of the wheel.
I hope this helps someone. I could have used this information this morning when doing a little final sanding on my iPhone case at https://www.instructables.com/id/Stainless-Steel-IPhone-Case-wBelt-Loop/