Bafang BBSHD minimum cadence RPM ?

myozone

10 mW
Joined
May 1, 2011
Messages
24
Location
West Cornwall - UK
I know the spec of the Bafang BBSHD mentions 130-160 RPM but this is way beyond most normal cyclists and people say the BBSHD likes high revs. But what would be the sensible lower/est limit without lugging ? I'm thinking on 52Volts. I guess I could limit the current (amps) but would that be counter productive?.
 
I ride an Ultra, but I think we're talking about the same thing.

I watch the watts/amps. That tells you exactly how you're loading the motor to my way of thinking. If you look at the charts, my interpretation of them anyway, says rpms are not nearly important as some say (within reason). We're talking electric motor here, an absolute torque monster at that, not a small displacement 2 stroke motor that needs to stay in a narrow power band to make power.

To put this into practical terms, say riding on level pavement, I very often leave a stop sign in 4th or 5th gear, finding it very easy to keep wattage under 200w or even 150 as I accelerate in no particular hurry. That's VERY low loading that can't possibley hurt a thing.

Try that from a stop while half way up a hill, maybe while in a hurry, and you're going to see wattage well over 1000w. THAT'S a significant load that could have been minimized by dropping down to 1st or 2nd gear.
 
Thinking about it that makes sense, I was thinking current(amps) would go through the roof at low RPM's <60 generating lots of torque and also heat, but going easy on the throttle accelerate slowly in turn keeping the current low. I don't have any ebike's so my thinking is was more from electrical/engineering experience. What concerns me most is having too high gearing on my donor bike 28T rear cog and the BBSHD standard 46T on 26inx2.10.
 
Gears, whatever you have, are generally about the speed (or range of speeds) you most often frequent, and your cadence level to maintain those speeds. For instance, if it seems like you're pedaling like crazy to do 15 mph, you're probably geared incorrectly. Just deal with it.

I would put the bike together and ride it. Then you know what's going on.
 
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