flyinmonkie
10 kW
Well, I have begun my chopper build. It is off to a slow start, but I am tackling the hardest problem first. The bike has a 4.5 inch wide rear tire, which is really cool, but makes it a bit hard to sort the drive. It is a single speed with a BMX freewheel and chain and a huge hub. I've relaced a standard cassette hub in and swapped out the axle for the factory one to get the length. Unfortunately that doesn't leave me with as much room for extra sprockets as I want on the cassette. I have used an old school uniglide hub as it is threaded on the outside for the final sprockets that held them all one. A standard right side BMX freewheel fits the threads on the cassette. And that is what you see in the hub picture.
My drive idea, which will work in a standard wheel no problem, is to fit maybe 3 sprockets on the cassette for the motor to drive through a derailleur. There will be one chain from the gear reduction on the motor to the cassette hub. I will hold those sprockets on the cassette with a freewheel threaded on the outside of the cassette (in place of the outer threaded uniglide sprockets). A separate chain will run from that freewheel to the cranks.
This configuration will give me 3 gears for the motor, and the pedals will be a single speed. I can gear the pedals to actually be some help while under epower. With the freewheel on the cassette I will not need a freewheel crank. This is because the freewheel on the cassette will keep the motor from driving the chain connected to the pedals. It does mean 2 chains running to the rear wheel, but they will both be on the right side and only one will turn under motor power.
As I said, easy to do with a standard wheel, but with my 4.5 inch rear wheel, a bit more of a challenge. I am trying to find a 170mm rear cassette hub with a uniglide body, or uniglide compatible body. Not an easy task. My least favorite option is to cut the hub and weld in an extension. I am leaning towards an internal geared hub, but I am not sure if I can get a seperate freewheel on the hub with the standard drive gear.
Well, as for the rest of the bike. The motor and probably a single stage reduction will go between the rear wheel and seat tube. The batteries, controller, and charger will go in front of the seat tube and over the chain guard. The bottom bracket is huge, so SLA's fit nicely either way.
Thanks for reading the book I just wrote, it should answer most questions, but feel free to ask any more, or provide your thoughts. Enough already, on to the pics.
My drive idea, which will work in a standard wheel no problem, is to fit maybe 3 sprockets on the cassette for the motor to drive through a derailleur. There will be one chain from the gear reduction on the motor to the cassette hub. I will hold those sprockets on the cassette with a freewheel threaded on the outside of the cassette (in place of the outer threaded uniglide sprockets). A separate chain will run from that freewheel to the cranks.
This configuration will give me 3 gears for the motor, and the pedals will be a single speed. I can gear the pedals to actually be some help while under epower. With the freewheel on the cassette I will not need a freewheel crank. This is because the freewheel on the cassette will keep the motor from driving the chain connected to the pedals. It does mean 2 chains running to the rear wheel, but they will both be on the right side and only one will turn under motor power.
As I said, easy to do with a standard wheel, but with my 4.5 inch rear wheel, a bit more of a challenge. I am trying to find a 170mm rear cassette hub with a uniglide body, or uniglide compatible body. Not an easy task. My least favorite option is to cut the hub and weld in an extension. I am leaning towards an internal geared hub, but I am not sure if I can get a seperate freewheel on the hub with the standard drive gear.
Well, as for the rest of the bike. The motor and probably a single stage reduction will go between the rear wheel and seat tube. The batteries, controller, and charger will go in front of the seat tube and over the chain guard. The bottom bracket is huge, so SLA's fit nicely either way.
Thanks for reading the book I just wrote, it should answer most questions, but feel free to ask any more, or provide your thoughts. Enough already, on to the pics.