Building an off-road all-terrain wheelchair

Cliffleach01

Finding my (electric) wheels
Feb 20, 2021
7
0
Hi, I'm Cliff Leach and I am building an off-road all terrain wheelchair (this will not be used on-road and will only be sued at walking pace) .

I am a paraplegic and this is version 3.0 of the project, version 1.0 was purchased but had rubbish build quality and was all about speed, v2.0 cannibalized this and is my 'test-bed' for the dynamics of the system.

The cheapness and power available now using standard electric bike components offers me a lot of potential and I wanted to share with people my experiences of the design and build.
There are several design constraints, for example I want V3.0 to be able to break down, simply and easily and fit into the boot of the car. |At minimum my RAV4, ideally into my Mini Cooper hatchback!

Fortunately I am a skilled and experienced engineer, that DOES NOT mean that I think I know much about e-bikes, hence my reason for joining this forum and hoping that other's out there can help with my questions.

I am using an off-the-shelf Chinese 500 watt 36 volt hub fitted to a 20x4.0 inch rim. This will both fit one of my space constraints and also allow lower ground pressure and shear force when applying power on lose ground. It also works with my two 36v batteries (one 7.5 |AH, the other 20 AH)
So the first problem; I live in England and I am finding it the devil of a job to get hold of any 20"x4.0" inner tubes or tyres in this country, does anyone know of anywhere that I should try? Supply times from Hong Kong and China are grim right now.
 

Raboa

Esteemed Pedelecer
Aug 12, 2014
715
273
52
Amazon and eBay might be a good source.

eBay for example:
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This company stocks inner tubes and tyres (,I have never used them)
 

vfr400

Esteemed Pedelecer
Jun 12, 2011
9,822
3,985
Basildon
Which 500w motor are you planning to use? Most would be too fast at 36v if you want walking pace. That would mean that they'd lack torque and overheat.