Electric wheel chair converted to fast trike

hellspcangel911

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Hi all,
I just picked up a 1996 Fortress 1700 Personal Mobility scooter (aka electric wheel chair). it has a 24v motor with brake, controller, chain differential... all mounted on a nice compact steel frame that detaches from the forward section by one screw- making it a great trike build. the only problem is that the stock speed is about 5.5mph.

Originally the unit is designed for people up to 350 pounds, the weight of the unit without batteries is over 120 pounds. Calculating the driver will be either 100 pounds (wife) or occasionally 200 pounds (me, :mad: ) i'm thinking the easiest way to make it go faster is to put some bigger wheels on it. I could make it 36 volts or even 48 but that would require a new controller... in which case I might as well rip out the DC motor and strap on the two stroke sitting in the shed.
im thinking old bike tires would work? i have a set of 26" mtb wheels i should be able to lock to the axle.
thoughts? advice? brutal honesty please.

(this will only be used for the fun of it. if anyone can think of a better use for this set up, let me know)
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If it was me, I would retain the motor and portion of the frame it and the rear axle sits in, and controls. Devise a way to mount it in the frame of the 3 wheeler driving the bike wheels off sprockets attached to the axles.
 
I feel like adding sprockets to the system would be cumbersome as each of the rear wheels would require their own chain/sprocket drive to utilize the differential.
do you think the motor would need to be geared in order to properly function with 26" or 24" wheels? I think it has enough torque that bolting the wheels on directly should be fine.
the issue later will be freewheeling, it looks like the motor has a electric brake leading off the controller, I would just put in a switch to turn the brake off as needed (down hill) and fit in a mechanical brake for safety.
 
How to mount the wheels onto those axles (and widen them), is the big issue to me. Tires on the chair look to be about 8", if they were 3 times bigger, you could go 16.5 mph, right?
This looks like a big time fabrication idea. Might be easier to just use the electronics and motor into a normal 3 wheel bike. motor looks to have internal gear reduction.
 
7 or 8" wheels, correct.
Its hard to tell from the photo, but the chain drive is actually 1:1.
I wasnt planning on widening the rear axle (though I agree it would be better from a stability stand point).
the unit disconnects right infront of the seat post, i might even cut it up a bit before that, right after the motor support bar so the 26" wheels, though narrow, will clear the frame.
16mph does still seem slow considering the hassle of the project. I guess I have to start somewhere and then play with the sprocket sizing later.
 
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