Wheel design

---

17mm load-bearing axle

We take a stock bicycle wheel,

and remove the ball-bearing and inner ball-bearing holder attachments from the wheel-hub.

We add 1mm threads to both outer-extensions of the hub.

The OD of these extensions is about 35mm.

We use a 48.3mm OD seamless pipe (schedule 160) with a wall-thickness of 7.14mm (ID 34.02mm) to create sleeves.

We create a sleeve with an inner diameter of 35mm on one side.

We add 1mm threads to the inside of the sleeve on this side for 8mm.

This side of the sleeve is screwed into the outer-extension of the hub.

On the other side, it is bored to a 40mm diameter with a 12mm depth.

A 6203 bearing (40mm x 17mm x 12mm) slots into this bore.

The 17mm axle fits inside this bearing.

The total width of this sleeve is (8+12) 20mm.

We also use a bearing between wheels for the wheel-pair.

Since this bearing fits between wheels and we want to minimize spacing between the wheels in the pair,

we only bore the sleeve to a 6mm depth on the bearing side (instead of 12mm).

The bearing slots halfway into one wheel's sleeve and halfway into the other wheel's sleeve.

These sleeves are therefore (8+6) 14mm wide. 

We remove 2mm of material from the outside of both these sleeves, for an OD of 44.3 mm.

We create an addition sleeve (28mm wide) that is bored to 44.3mm. This sleeve serves to align the 2 wheel-hub sleeves and hence the wheel-pair.

20mm lateral-balance axle

The bearing used in this case is 6004 (20mm x 42mm x 12mm).

A pair of single sided sleeves is created for each wheel in this case.