When I originally designed the project, I had the first stage reduction at 4 to 1 resulting in a 60 to 1
reduction at the crank. The motor I was using at the time was 6,000 rpm, so I could pedal along with it.
The result was too much torque causing the rear cassette to skip and break chains. So I changed the initial
drive ratio to 2.25 to 1 which transmitted less torque and more rpm and made the rear cassette and
chain happy and also resulted in using the larger sprockets for the same speed engaging more teeth.
I haven't had skipping or chain problems since.
For the speed run I changed the initial ratio to 1.75 to 1 because I wanted to be using the larger rear sprockets
at high speed and power. The crank was approaching 500 rpm, so the drive train was spinning 5 times faster
than what is normal.
I would say the power was approaching 10 hp. If you watch the display panel on the run it shows the Kw in
the bottom left hand corner.
The short chain to the crank is a BMX chain and the derailleur chain is standard.
Just to let you know, I am not posting stuff just to draw attention to myself.
I would like to add that I post because I hope I am contributing something of value to others like
Matt S has done. I hope to think we are all trying to push the envelope and take each other to new
heights. I think I have helped explore the derailleur gear change set up possibilities.