Would field collapse come into play?



Using wheel size, cadence and some nifty formulas the rear wheel of a bike can be logged. Using the specs of a 350w Geared hub motor @ 270 RPM, 500w geared hub motor @ 325 RPM Both Weighing 3.5kg. a 250w unit is lighter -.5kg but has a higher gear reduction. Side Note could you imagine fitting a 32” rear wheel on a road bike. Interesting.

What type of problems would I run into pedaling past this RPM threshold, that happens to be quite low. [< 52/11 700c 80ish cads.]? DD Hub Motor’s rolling resistance does change incrementally past the Hand Spin test where higher RPMs are at play. Overvolting a Geared Hub motor could help. The planetary would no doubt pass this safe overvolted limit. Would field collapse come into play? Obviously, Temp. would have to be monitored. Would the electro field come into play at all with a geared hub motor at say >425 RPM that someone knows about? Is their maybe some source? “Web source, Documentation, Formula”. about or can point me in the right direction. There was something on the web that I didn’t bookmark and cannot find discussing RPM limits on geared hub motors other than Manf Specs and Wear. Any Help would be appreciated. Sorry for the heavy content but that is why I’m here. Thanks.


After reading the internet on this question. Surly more info is out there. The only thing remotely problematic is a wash boarding effect from the coils and magnetic field unless you cut power to the motor. SS relay & speed sensor maybe, not in the plans. Purchasing a rear geared hub motor and experimenting is the only path to this Quest. Unless?


Active member
Local time
1:44 AM
May 7, 2022
This forum may be more helpful to you.