by rlnguy » 04 Dec 2023, 01:25
Assuming OP was talking about the rear wheels, I offer this information.
Street used the larger tire because it gave higher speed, Using the 3.00-8 would slow it down, and affect the seat and caster angle.
Most Street chairs sold in the US had “no flat” tires-(required by most funding agencies).
At that time, Permobil used a one piece tire rim/hub, so changing a flat free tire required a whole wheel and tire.
Permobil later changed to a 2 piece rim, and a separate hub, to attach it to the motor. It is possible to change to the newer design.
Changing tires is much easier with the split rim. There are a couple things to be aware of.
Originally, the hub for the motor shaft had 4 M8 threaded holes, to attach the wheelrim.
The later (and current version) only has 3 M8 bolts to attach the wheelrim. Also, the newer hub is “permanently” attached to the motor shaft with adhesive. I doubt you will find any of the 3 bolt hubs available.
If buying wheels and hubs from an online source, you want to make sure you get matching hubs and wheels.
I don’t know of any source for grey, non-marking tires, or for any flat free tire, in that size, but 3.50-8 tires are common on garden tractors and other outdoor power equipment.
You might be able to cut the old, worn out, tire off, with a sharp knife and install tires and tubes.
I’ve done it, but it wasn’t easy.