Simple "V" belt motor drive does work

professor

professor

New Member
The idea was to get away from chains, idlers and a jackshaft because there was a lot of drag just spinning this stuff.
Went to a 20 inch bike rim attached to the spokes as a wheel pulley and a 2 inch one on the motor. This was too fast and slow to pick-up. went to a 1 1/2 inch drive pulley and was better- still fast and had some belt slip on take off. Ideally, I think a 2 inch drive pulley with the same size rim attached to another rim of the same size, would gear better.
I used a 3L belt and a 4L drive pulley ( these are sized in 1/8 increments, so a 3L is- 3 eights and a 4 is 4 eights (a half inch). Motor is 450 watt.
 

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very cool information .. How did you attach the rim to the wheel.... that is something that would be good to know.
 
I set the rim on the wheel and centered it to the rim ( I should have trued the rim FIRST, since the factory truing was not perfect- ran out about a 1/16"), with a caliper (a simple caliper - not a dial job is all that is necessary), getting the same distance all around. You need to set the wheel on something solid.
Then I used clothespins and carefully clipped them all around to hold the "Pulley" to the spokes.
I made small metal tabs to go between pairs of spokes- they fit between the spokes and capture each spoke pair. I braised a spot on each one to the "Pulley" . These tabs keep the pulley from beng able to move from position, rotationally wise, on the wheel, but the rim can be pulled off. So I drilled a small hole on each side of each spoke for a wire to wind around the spoke and retain the pulley from being pulled off.
NOW, after using the bike, I hear a little click sound, and that is the rim moving a tiny bit somehow.
Next I plan on using some kind of hard setting glue to glue onto the little wires/spokes and tabs. I am thinking of a product called SealAll, that is a gas-proof sealer ( I love the stuff)- or JBweld- that would probably be better.

as I mentioned, I think the ideal would be a rim riveted to the side of another rim- no spoke mounting involved and better gearing. But this would probably mean frame mods to accomidate the wider set-up.
 
I saw a few times belt drives on e bikes (only one in person - other on internet) and all of them were using car pulleys (car alternator stuff - belts and pulleys with "ribs"). The one I saw personally was mounted on the axle - outside of the rear fork. The others widened forks or (one case) replaced sprocket with said pulley.
 
I did look into a car type belt but could not find a pulley small enough for the motor, I was going to cut the belt down (after I found one to fit) to 3 ribs and use it on the bike "Pulley", so I went to the V belt where belt and pulleys are readily avalible. The belt does not slip at all on the big "Pulley". There are different ribbed belts and it may be that the car applications are not the same as industrial ones.
 
My belt sander is driven by the ribbed pulleys and belt (1.2 KW , 2920 rpm). Motor pulley on that thing is like a 1 1/4" and the belt is at least 10 years old. Don't know if we understand each other - ribs are positioned across the belt , not along it. Belt is about 1/2" wide (maybe less - it's metric), so I believe that with 3/4" belt you'll be fine (if you can stuck pulleys between fork and rim/laces ). However , if V belt works , don't fix it until it's broke.
 
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