New trike with friction front drive

mlcorson

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I found this trike at the junk yard for a ridiculous $20! Single speed back pedal braking and broken front caliper brake. The back tires and tubes were shot. I picked up a used set of 24" tires and tubes from Craigslist. I removed the front caliper brake and I installed the friction drive from BMP on the front wheel. The whole bike was very wobbly even without the motor. The frame is nothing but a square tube...I was surprised how it sort of twisted when i rode it. I cut up an old bike frame...from where else? The junk yard, and strengthened the frame by welding a top tube and several side supports. Its better but the weight on the front fork still is bit wobbly. The grandkids are going to help me decorate it and pull them in a parade in our town in May. I've enclosed pictures of the frame and a picture of the drive train. It seems with BMP's new jack shaft set up I could easily mount a sprocket on the left axle and convert this to rear mount chain drive. I'm thinking I could put a slot/keyway in the axle shaft and mount a sprocket. HAs anyone done this? Any problems with that plan? Would the bike pull over to the left when applying power to the motor? Since you'd only be driving the left wheel.
 

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mlcorson, I like what you've done there so far, in stiffening the frame.

What you are describing is basically a split power application - pedal power driving only the right side half-axle at the rear, and gas power driving the left side half-axle when in use. Which is a workable, and actually fairly common, solution to the issue of applying gas-assist power to a delta trike. As I said, it is workable, and the control issues engendered by powering only one side are fairly easy to develop response habits to.

My question is, since you want to make the transition to a lower engine mounting site and apply power to the rear, why not go to a small additional effort, and bring the pedal and the power sides together at a mid-drive, and drive BOTH rear wheels either by pedal or by gas power? It is remarkably simple to do, and if you do it correctly you can add multiple gear capabilities in a most straight-forward fashion.
 
Simple, yes I like the idea. So how's it done? Install a new axle shaft or couple the 2 axles and apply the sprocket to the coupler. Make sense? I'd like to see it...any pictures.
-mlc
 
Mine is wobbley to, I learned that trikes aren't supposed to go 25,on 1 of my next 1's is guna b a bigger trike that I already have and a pit bike 50cc w/tranny motor setup.
guna try to mount the engine behind the seat post.
 

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Thanks for the article post mlcorson. I have a good condition old Columbia trike sitting in the garage and thought about going the bmp way as well with friction on the front tire. It is a two-speed model though the shifter often derails when pedaling.
 
Trikes

I also had a pretty good wobble problem on my trike. I cured 90% of it by using a strut (brace) on either side of the bike from the seat down tube to the rear end. The thing wanted to flex and that was OK as just a bike. It makes it real unstable as a motorized. You can see the chrome strut I used in the pic. Before I regained my sanity and regeared it, I had it up to around 55mph. Of course, tall trikes are still unstable(Wants to flip) on corners. But it can be made stable enough for easy riding. Just slow way down for the turns.
Big Red.
 

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At one point I wanted to motorize a Sun EZ-3 SX recumbent trike. I could have gotten a good deal on a used one, and at the time Staton made a kit for it. Now they only make a kit for the 3 times more expensive EZ-3 AX aluminum frame high end trike. Oh well.
 
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