Smart Grinder- Belt Grinder Small Wheel Holder Set Include Holder- Knife Making 

The distance between the mounting holes is 55 mm. And the hole diameter is 11 mm

Important:

Small wheels are "small" :) and hence will rotate at much higher RPM than the Drive wheel RPM.

The smaller the wheel you use, the higher the speed.

For example: If your drive wheel is 100 mm running at 3000 rpm motor, then the speed of the 12 mm wheel will be 25000 rpm. 

Therefore bearings will not last long if you don't have a way to reduce the drive wheel speed. It's a must that small wheels operate a much lower belt speed. 

The bearings can be replaced when they get worn-out. They are type 6200. You can easily source them on eBay. 

Set Includes the following wheels dimensions:

12 mm diameter

15 mm diameter

20 mm diameter

25 mm diameter

30 mm diameter

All wheels are 65 mm wide made from Steel.

Thank you