I came across the following excerpt about how to mount wheels:

The most robust system is the dual bearing system. In this, the wheel axle is mounted on two bearings and chain driven. This takes all of the load off of the motor and puts it on the chassis/motor mount. It also allows for easy adjustment of speed (or power) by changing gearing ratios of the sprockets

Does anyone have a picture of what that might look like?

What I picture when I read that is the following:

  1. Motor shaft has a sprocket on it
  2. A chain connect this sprocket to another sprocket on the wheel shaft
  3. The wheel shaft has a bearing similar to this one mounted to the chassis

How does this make for a dual bearing system?

  • 3
    $\begingroup$ you just need to have two such bearings, one on each side of the wheel- wheel would be in between two chassis rails rather than sticking out of the chassis. something like andymark.com/products/am14u4-kit-of-parts-chassis. That said, there are implicit constraints on this "most robust" business. One could build a more robust system with a custom motor with integrated bearings of appropriate spec and no need for a chain-sprocket adding more points of potential failure. $\endgroup$
    – Abel
    Jan 3 at 13:11
  • $\begingroup$ Thanks @Abel makes sense. What described above makes sense to me in many ways, including economically. If I don't make the chain too long, I could position the motor closer to the wheel and then with the equipment I have, I wold be able to house the entire thing in a metal box to further protect from snow, dirt, etc. $\endgroup$ Jan 3 at 13:37
  • $\begingroup$ I think two bearings would help take bending or moment loads on the axle (eg from side forces on the wheel where it contacts the terrain) ... the chain can take up variations in alignment between power output (eg motor) shaft and axle. A pair of flexible couplings or spline-plus-double-U-joint half-axle-assembly like on a car suspension could also be used, in principle ... but probably more complicated $\endgroup$
    – Pete W
    Jan 3 at 15:44

1 Answer 1


This is just a very simple axel/drive configuration

If you consider the example to be for a two-wheel axel, it make perfect sense. The live axel is supported by 2 bearings & is connected to the sprocket, and it makes sense.

Even motorcycles have a two bearings per wheel, though the sprocket mounts to the wheel directly. The method given is just a simple example.

  • 1
    $\begingroup$ Don't most motorcycle wheels have a sealed bearing each side of the hub? Similar to bicycle wheels, but they just have simple roller bearings. $\endgroup$
    – Solar Mike
    Jan 4 at 13:28
  • $\begingroup$ @solar, yes, 2 bearings stuck together. I will edit. $\endgroup$
    – Tiger Guy
    Jan 4 at 13:43
  • $\begingroup$ I dont think I was clear enough in my question, but the system is a differential drive robot with one motor per wheel $\endgroup$ Jan 6 at 2:06
  • $\begingroup$ you'll need more bearings, then, most likely, since the axel is split $\endgroup$
    – Tiger Guy
    Jan 6 at 4:39

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