Brushless eBay!!! Bought.

[Burgerman]

Thank you! Let me know how much.

We should get 3 drawing done for total width fully machined, bolt on 3.00J inch and 3.75J and 4.25J inch external rims.

For 3.0J for 3.50 tubeless tyres.
The 3.75J rim for 110/80.
And the wider 4.25 one for 120/70 tyre.

Total widths with tyres of 3.5, 4.2, and 4.75. All about 14.5 to 15 inch overall diameter.

Or 3 stepped spacer rings made up.

[shirley_hkg]

How many poles are there ?

[Burgerman]

20 Magnetic / electrical pole pairs.

[Burgerman]

But its more in reality because they overlap, and each set of poles is used to both pull, and push in reverse as the current is reversed. So behaves like 40 with overlap. More coils than magnets...

[Burgerman]

So 40 magnets in N/S pairs. And its not adjustable here! Even with factory, so all must be the same.

[shirley_hkg]

[Burgerman]

The brake on my new chair is really quiet.

[Burgerman]

In order to fit the 120/70 or 110/80 x8 tyres, you need to add 5 spacers to the wheel.

Either 50mm for 110 tyre or 60mm for 120 tyre long, 8mm bore. Those can be bought on ebay.
Then add 1mm thick alloy sheet bent into a ring. You need 2 per wheel.
One goes inside the external rim.
One around the outside of the rotor drum, on the reduced diameter part. One slides inside the other as a tight fit. Then use those alloy solder/braze rods to join ends and fit together as a 'stepped ring'. Now you have a rim, that was 1.75 wide, at 3.75 (or 4.20 inch).

These are for the Duro tubeless tyres, and can be used with a 4.00 x 8 heavy duty (90 degree valve) tube as fitted to trailer wheels. Those are heavy and good solid quality compared to what we are used to. As soon as I get off this bed I will do pictures as I do it!

With 110 tyre (4.33 inch) instead of 3 inch, the chair will go from 24.85 wide, to +2.66 wider or 27.51 inches. Not bad as the arms are the same. Overall diameter 8mm (or 1/3rd inch more).

110/80 - 8 tyre:

[shirley_hkg]

Then use those alloy solder/braze rods to join ends and fit together as a 'stepped ring'.

You put them together by welding ?

These are cast aluminum . Not good for welding .

Damage to the rare magnets too ..

[Burgerman]

No. Assemble with bolts, as before, but with 50mm spacers. And with a 50mm deep 'stepped' ring made from 1mm aluminium sheet, to locate the rim and to take the load and to fill the gap. THAT ring will be brazed at low temperature. On its own. Not to the wheel or motor.

[shirley_hkg]

Alternatively , the complete outer rim can be machined .

Still don't get how you seal the motor half air tight .

[Burgerman]

Tube... I could machine a rim from your image, but would need to end p with a 3.75 or 4.25 width. And not sure that the bolts alone offer enough strength. So must use the same spigot as the original rim.

Also I think that you can use tubeless on the original rim if you seal it with O ring. Its tapered and will seal the feather edge on a tubeless tyre..