Jack shaft shift Idea for DIY Bents

Vari drives are fascinating. So basicly it is just one half of a CVT. In a cvt the centrifugal force on the drive pulley controls the belt tension, but in a vari drive you manually control the belt tension. These would make a neat little manually transmission. I bet you could make one half the size of a scooter CVT by hacking one in half and making two vari drives from the pulleys inside. Rig the tensioner to your shifter cable and it would be a sweet shift kit. Or get a larger one and put it through the bottom crank bracket like my original idea and run a belt w/ tensioner off your motor to the left side, and have your chain ring off the right side, a nice compact wide range transmission, youcould milk every last drop out of a china girl.
 
It has to pivet in order to work. I was thinking mount it like a Wizzer under the seat.I will post a picture of a compleat one today or tomorow..........Curt
 
mmmmm..... suicide shift cruiser? i saw neet times' superbikes (engines were easily concealable being rackmounts..with cvts added neet times has bikes that dreams are made of) . and i found a picture of a double-jackshaft cvt mountain bike, straight piped with a blue gas tank on the backrack...the double jackshaft cured the wideness issues...besides maybe skimming your ankle on the secondary driven clutch....but you dont ever need to peddle masterpieces like those. and in all the tractor forum skimming....i found how many different brands used the vari drive in place of the more expensive hydrostatic option, and still couldn't believe i've never saw one.thanks for taking the time to post it/ explain it, because this is a horse of a different color
 
Here is a compleat verydrive with the pivit on the bottom. One belt down is about1 1/2"or 2" pully size and one belt up about 53/4" size. Makes for a good range of speed when they switch side to the opaset. If it were made smaller so you could use a 1/2" belt insted of 5/8" and about 3" size pullys it would be perfict for motor bike?
This on is stamped steel and a lot lighter. My son is a machinest and he talks about useing aluminum with hard steel insert. Might have to use a second jack shaft to get the right reduction, something like the 4G-T belt setup on the new 4 stroke kits. use a belt insted of chain then put this between it and the wheel...............Curt

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veridrive 001.jpg
 
NOW someone told me that ther is a smaller industrial on. And that you need a spring loaded tensioner on one belt to maintain the tension while moving through the ark.
 
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I've drilled out the rivets on the front crank and bolted a #25 sprocket with some spacers for the jack shaft I made and I was able to change gears on the crank and the rear wheel. The speeds I reached were crazy fast way to fast for a bike though
 
Southpark247 said:
I've drilled out the rivets on the front crank and bolted a #25 sprocket with some spacers for the jack shaft I made and I was able to change gears on the crank and the rear wheel. The speeds I reached were crazy fast way to fast for a bike though
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Freewheel?
 
Clausing drill presses and J head Bridgeport milling machines have a long successful run utilizing variable speed transmissions. In fact every manual variable speed transmission in a machine tool uses one. Simplicity and high torque transfer are the hallmarks'.

Tom
 
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