Yokomo mr4Bc wheels
 

What is the difference between the Yokomo mr4bc wheels and the Yokomo mx4 wheels. Is it the hexagon drive? The original mr4 BC had the hexagon drive they had a 10 km offset, and a 6.5 km offset. I have the special 3 eared drive. I had thought about buying the original drives. Has any one converted to the bmax drives on the BC or mx4

The wheels are the same, the hubs are different in that the MX 4 hubs support up to six mounting screws the MR4BC has three. The centre hole diameter is larger in the MR4BC as it used a larger diameter axle than the MX4.

The wheels of the mr4-bc special were different from the mr4-bc (which were the same as the MX-4: big hex-shaped fit).
As far as I know you can not fit the special wheels on the standard bc or mx4. They are easy to recognize from the front too: mx4 and bc are spoked, bc4 sp is a plain disc.