These wheels were 350 x 8 tubeless tyres on steel 8" x 2" rims with four mounting holes at 115mm PCD or 107.5mm radius if you prefer. After several days staring at all the bits a cunning construction plan filtered in to my brain...  I wanted Tank steering, with chain drive to the wheels, simple compact and elegant engineering construction. No yucky steel brackets, added on bits etc, much thinking, but little cutting!!! I chose these wheels because they are readily available, cheap, chunky, strong, tubeless (less puncture problems!) and I spotted them in a local car accessory shop...

Here the spacers and the cross bars that join the gearboxes together are being drilled and tapped to M8 in my old lathe in my bedroom. The furniture polish (Mr Sheen) makes really useless cutting lubricant... But we use what we have   The Girlfriend is DEAD pleased! She LOVES finding metal swarf in bed and stuck in her feet when she gets up...  Everything had to be machined alloys and stainless steel cap screws... No bodging here... Oh AND Cheapish! OK, enough threading and turning...

 I decided to check out these 3 year old "used" wheelchair motors and look inside!  They DIDN'T look like this!  First I stripped them and tipped about 2 cups full of black burned carbon brushes!  And rust... No wonder they were a bit hesitant, and noisy!   Surprised they worked at all... No room for anything to turn!  If you have a powerchair that sees daily use then you must blow the dust out of the motors and replace the brushes AT LEAST annually. If not you are going to be stuck sooner or later. If you do they may well last forever. A important lesson learned.  Oh, you can just see my home made Gas Turbine's tailpipe sticking out at the top right of the picture if you click it!

OK They were completely stripped cleaned in soapy water, re-greased bearings, new brushes, and the commutator was cleaned up with a bit of fine emery paper. Good as new!

Gearboxes were cleaned only externally, for now, but I will be getting new internals, and new cush drives soon because they are clunky with lots of backlash... These will hopefully come from Rebel Replicas. In the meantime it will have to be noisy! (excessive backlash from too many wheelies previously) It will not break.

Those old brushes...These are a comparison, between the old motor brush and a new one. Some were much worse than this one on the left but I threw them out before I remembered to get a picture...

This whole project started as "something to do with all the spare wheelchair bits" I had kicking around, and the fact that I have a lathe in my room... Oh, and because I can...

Its design had to be as "close coupled" as possible (wheels as close together as possible) so that the "tank style" steering does not cause problems and its' "smooth" and controllable. Too far apart and it will struggle to turn and tear up tyres and carpets with my weight on it.

Did I mention 4 wheel drive? Well for tank style steering to work you need 3 things:
 - 4 wheel drive
 - LOTS of torque
 - Wide overall track compared to the wheelbase

TaperLocks shown, allow Sprockets, Pulleys etc to be fitted to standard sized shafts like 20mm in this case. Extremely useful and solid fitting. They lock onto the shaft, not needing keys or splines although I fitted a key anyway for security.

A drive chain to connect the front two wheels to the rear ones achieves 4 wheel drive easily. These fit using TaperLock fittings as shown


OK too much brain work, my head hurts, time for some relaxation time So I am taking a rest.

This picture shows the NEXT larger taperlock fitting sat on the shaft as well as the sprocket one.. This one will allow me to also fit a modified V-Belt pulley. This pulley will have the "V" bit machined off, and four M10 holes tapped so that I can bolt the wheel on!  Sounds worse than it is of course!

This pulley is not shown here. This is how I intend to get power to the front wheels, with a 19 tooth sprocket on both the rear and the front wheel shafts. These shafts are "keyed" but this is a bad way to transfer a reversing torque load. The sprockets (and the wheels) will all use these "taperlock" fittings. These locate inside the sprocket, and clamp securely on to the shaft as a couple of Allen keys are tightened up.

Construction started! Finally  Bit basic to begin with. But the plan is in my head...!

The angle bits are already drilled, and the following pictures show how the spacers, cross pieces, and side rails all fit together using long 8MM bolts. The cross bits that go between the gearbox have been tapped to take the M8 bolts.

Another view so you can see what I am talking about... This time with the threaded bar joining both sides. View as above - but different angle.