Thanks for that video, i think that's medium loud.. but we wanted a lot quieter didn't we.
It does sound like motor whine more than mechanical whine..
Maybe it's improvable with a different controller, which is the route i want to experiment with..
Per my previous calculations:
For keeping the stock RPMs here is an option if you want to do 52v..
42T chainring @ 48v: 93.75 RPM <-- seems a little high
46T chainring: @ 52v: 92 RPM <-- about the same as stock, need hybrid or mid mount depending on your frame geometry
I need a 48T chainring minimum to hit 30mph, so..
48T chainring @ 48v: 82.0 RPM <-- probably my average pedal speed
48T chainring @ 52v: 88 RPM <-- within acceptable range & less than stock - great
I decided to try to install it on my MTB with the mid mount and also the hybrid mount and mid mount..
Pedals tighten down on the ~123mm bottom bracket without using any of the included spacers.
I'm thrilled that i could switch out the 127mm bottom bracket and have more of a roadbike-like Q factor, dream come true! that's why i bought this drive!
Mid mount: Maxes out at 46T, might take 47T
Hybrid mount: 48T on a 13T rear gear just barely works.
In this picture i am hand-tensioning a chain draped over a rear 13T sprocket at about 80% intensity. You still see a little droop. When engaged with two hands, there's even more clearance indicating i can run a 12T sprocket but this would make my estimated top speed 28.1mph which is disappointing.
If i had a 29er with the same 2.35" tire then i would be doing 30.5mph on this gearing, so this is def a 26er problem.
This orientation with the hybrid mount looks quite good, the motor gets blasted with more air with it sitting more upright than usual.
I'm quite sure a long mount would be adequate to get gearing good enough for my 26er, but it is way too long.
A mid mount that's 1 inch longer would give me another 1/2 inch clearance and give me enough room to get 30mph capable gearing without needing to resort to a weaker 11T in the rear.
Chain wrap should be good when i replace the torque sensor arm with the one included in the bag for the hybrid mount, should have 33-40% of the gear wrapped which i imagine is adequate for such a large chainring. The torque sensor arm should have more travel, so i think the torque sensing might work better than nervagon's and be less pulse-y, we'll see.
A top speed around 28mph should be enough to torture this motor and find it's true power rating. I have plenty of roads here with a slight long grade and i'd like to see if i can load this motor right @ 1000w.
If the motor can take this for an extended period of time without melting, i call this a promising motor & i will work on some mods that increase the power and speed.
If not, it goes on the recumbent where i can get away with a less powerful motor & i'll do the dual chainring mod or some goofy looking business with the 'inframe mount'
Off to buy a 52v 20ah battery!