D
Doug Goncz
Guest
I have a motor on my bicycle, an electric motor. It's mounted in the center of the main frame
diamond, and it is currently connected to the rear wheel with a flip flop hub and a 48 tooth track
cog I made. The motor pinion is 8 teeth. It can also be connected to the pedals, without
repositioning, since the left crank is a tandem crank, and so, has a chain wheel.
I made the first 48 tooth track cog from a BMX spider and a chain wheel. It was eccentric and
wobbled. The second came out great. I soldered a bottom bracket lock ring to the spider to give it
the thickness of a track cog.
The chain forms a triangle from the motor to the track cog, and placing the motor in the center of
the frame diamond makes sure that this triangle doesn't hit the chain and seat stays, because it
positions the motor on the bisector of their included angle.
I added a turnbuckle in front, between the head tube and the motor mount disc, to tension the chain.
I found (post "Ghost Cog", here in rbt) that it requires a lot of tension to avoid chain skips. So I
added a jockey pulley.
I removed the inboard pulley and side plate and reversed the bolt to go in from the post side. I
capped the bolt with an M5 cap nut. I trimmed the remaining cage to look spiffy. I selected a point
along that bisector I made the bracket from the mating part, freed from the rest of the derailer by
drilling out the rivets, milling the stamping until it was symmetrical, grooving it, and bending the
two rivet hole areas out perpendicular to the post.
I selected a point on that bisector I mentioned, and drilled a hole to fit the outside of the
bushing that takes the post. I tried hard to get it square to the board. I should have taken the
board off and used the drill press. It comes off easily with three hose clamps and an electric
screwdriver fitted with a
5/16 socket.
I put the bushing in the far side, and marked, drilled, and screwed in one tab, then did the same to
the other. Then I removed the whole bracket and drilled out the hole to clear the tensioning spring.
I removed the board, finally realizing how helpful that would be, and put the jockey, spring, and
bracket with bushing together with the snap ring, and installed the screws. It dragged horribly. I
made a few careful bends here and there with a vise mounted bending brake I have, and pliers, and
got it almost working. To finish, I used my arbor press to cram the bushing down into the board,
since I had discovered my milled and bent ears were one thickness of sheet steel pround of the area
around the bushing.
I fitted the chain and tensioner, and it's ready to ride. Whee!
The goal of this project is to add virtual mass to the bicycle with the motor and an ultracapacitor.
It should add more than the mass of vehicle and rider, with a mass cost of, say, twenty pounds. By
charging up the cap approaching a hill, I should be able to stay in gear right to the top, without
bottom out on the lowest gear. Believe me, it doesn't matter what that lowest gear is, once I hit
it, I get very frustrated.
I have found that, in general, speeding up to approach a small hill is a great technique to get to
the top with less leg and lung strain. Long hills, you just have to tough 'em out....
The cap has enough storage to go down a couple hundred feet and have an assist on the other side. It
costs $3000.
I wonder if I can rent one somewhere....
Yours,
Doug Goncz, Replikon Research, Seven Corners, VA http://users.aol.com/DGoncz If a computer won't do
what needs to be done, lie to it. Don't try this trick on people.
diamond, and it is currently connected to the rear wheel with a flip flop hub and a 48 tooth track
cog I made. The motor pinion is 8 teeth. It can also be connected to the pedals, without
repositioning, since the left crank is a tandem crank, and so, has a chain wheel.
I made the first 48 tooth track cog from a BMX spider and a chain wheel. It was eccentric and
wobbled. The second came out great. I soldered a bottom bracket lock ring to the spider to give it
the thickness of a track cog.
The chain forms a triangle from the motor to the track cog, and placing the motor in the center of
the frame diamond makes sure that this triangle doesn't hit the chain and seat stays, because it
positions the motor on the bisector of their included angle.
I added a turnbuckle in front, between the head tube and the motor mount disc, to tension the chain.
I found (post "Ghost Cog", here in rbt) that it requires a lot of tension to avoid chain skips. So I
added a jockey pulley.
I removed the inboard pulley and side plate and reversed the bolt to go in from the post side. I
capped the bolt with an M5 cap nut. I trimmed the remaining cage to look spiffy. I selected a point
along that bisector I made the bracket from the mating part, freed from the rest of the derailer by
drilling out the rivets, milling the stamping until it was symmetrical, grooving it, and bending the
two rivet hole areas out perpendicular to the post.
I selected a point on that bisector I mentioned, and drilled a hole to fit the outside of the
bushing that takes the post. I tried hard to get it square to the board. I should have taken the
board off and used the drill press. It comes off easily with three hose clamps and an electric
screwdriver fitted with a
5/16 socket.
I put the bushing in the far side, and marked, drilled, and screwed in one tab, then did the same to
the other. Then I removed the whole bracket and drilled out the hole to clear the tensioning spring.
I removed the board, finally realizing how helpful that would be, and put the jockey, spring, and
bracket with bushing together with the snap ring, and installed the screws. It dragged horribly. I
made a few careful bends here and there with a vise mounted bending brake I have, and pliers, and
got it almost working. To finish, I used my arbor press to cram the bushing down into the board,
since I had discovered my milled and bent ears were one thickness of sheet steel pround of the area
around the bushing.
I fitted the chain and tensioner, and it's ready to ride. Whee!
The goal of this project is to add virtual mass to the bicycle with the motor and an ultracapacitor.
It should add more than the mass of vehicle and rider, with a mass cost of, say, twenty pounds. By
charging up the cap approaching a hill, I should be able to stay in gear right to the top, without
bottom out on the lowest gear. Believe me, it doesn't matter what that lowest gear is, once I hit
it, I get very frustrated.
I have found that, in general, speeding up to approach a small hill is a great technique to get to
the top with less leg and lung strain. Long hills, you just have to tough 'em out....
The cap has enough storage to go down a couple hundred feet and have an assist on the other side. It
costs $3000.
I wonder if I can rent one somewhere....
Yours,
Doug Goncz, Replikon Research, Seven Corners, VA http://users.aol.com/DGoncz If a computer won't do
what needs to be done, lie to it. Don't try this trick on people.
