In a previous post I’d demonstrated that wheels from a fatbike where the most aesthetically pleaseing on the wheelchair. Unfortunately, they’re too fat.

I tried to revisit some of the measurements I’d taken during a trip up Snowdon but all of my pencil notes had become eligible. Luckily however, part way up the mountain, I recorded myself saying that the wheelchair needed to fit through a 3′ gap. That’s 36 inches in total.

The fatbike wheels are 4″ wide, so 8″ for both sides. 8″ of the 36″ available space is too much. It would mean that 22% of the wheelchair width was just for the wheels. For that reason, I’ve had to revert to standard mountain bike wheels.

In addition to this, the seat was taking up too much room too, so I’ve had to redesign that also.

Here is the current mountain wheelchair concept drawing which will now fit through a 3-foot gap:

The only problem with this is that having a smaller wheelbase means it’s more likely to tip over on its side.

I plan to overcome this by moving all of the central parts of the frame lower down. it does mean that it will have a lower ground clearance, but that’s preferable to a wheelchair which falls over all the time.

On the plus side, this does mean that the wheels will be lighter.