So that I can do some testing, I’ve placed some obstacles in the garden which I can leave in place and see how the modifications I’m making affect the performance.
I was finding that on certain obstacles the wheels were just spinning and no progress was being made. To try and overcome this I printed a knobbly tyre but this made things worse. However, taking inspiration from the rock crawler world, I printed off the existing tyres but with much thinner tyre walls. This has resulted in softer tyres and made a huge difference to the grip:
It has been suggested that the final wheelchair have a pump which can deflate/inflate the tyres as required. This would be extremely useful but it would require consideration of the benefits, weight, and power requirements.