but to my mind this is relevant to a post about 2kw motored e-bikes: I have a DIY 3KW job (BPM, S12SH, hobbyking lipos) and a friend with an oxydrive 250w. There is a VERY steep hill we both use - his 250w hub motor hauls my 100kg ass up there without a problem (admittedly without the pupil dilating wheelies of the 3kw bike), and there is a distinct digging in around 6mph that correlates with this calculation. the more I use e-bikes the more I wonder why anyone needs more than 250W.why not?
power (in Watts) = torque (in NM) * angular speed (radians/s)
a 250W motor at 60NM will rotate your 700C wheel at 250W/(60NM * 2 radians *PI()) = 0.66rev/s, equals to 0.66 * 4.4m/s equals to 10.5km/h or 6.5mph.