This is an interesting page:
https://etrike.wordpress.com/2013/07/06/bafang-swxh-with-steel-planetary-gears-a-short-summary/
d8veh I still can't get my muddled, quickly ageing, old head around what motor RPM I would need for a 24" wheel with decent torque and 40+ km/h top speed WOT. In an ideal world I would like decent torque AND 45 km/h top speed on the flat WOT...
He's running at 35 amps. No wonder he shredded his nylon gears. They've done quite a lot of experimenting with oil cooled motors on ES. it's probably a good idea if light weight is important, but for the extra size and weight of a BPM motor over the SWXH, you get a lot more oomph for climbing. Even at 36v, a BPM would be able to hold 40km/h, but at 48v, it should be even better. I used to run my 36v one at 30 amps, mainly for climbing. It had a top speed on the road of about 22 mph, but it had real power.
I was out testing an Oxygen S-cross city today. It was easy to maintain 24 mph on the flat. It didn't have a throttle, but i'd be surprised if it would go much above 20mph without pedalling. I could still hear the motor assisting at 27 mph, but it was past it's peak power at that speed
What sort of bike are you going to put the motor in? There's a big difference between a road bike and a MTB when you get to that sort of speed.
In a 26" wheel a 328 rpm motor gives good power to about 27 mph before it starts to tail off, so that would be about 25 mph (40km/h) with a 24" wheel. You can change the rpm of any motor by using a higher voltage, so a 260 rpm 36v one will become a 346 rpm one at 48v or 312 rpm with 12S lipos.
