Does the EP8 have a cadence cutoff?

[Bad Mechanic]

I was riding my EP8 equipped bike today and was spinning a pretty low gear very fast, and I started noticing the power assist cut off at about 13.5mph. However, if I upshifted lowered my cadence, my cutoff seemed to go back to the normal speed.

Does the EP8 automatically cutoff above a certain cadence?

 

[DaveW2]

I think I can feel that effect. I have recorded a couple of rides on the STRide app and put the data in a spreadsheet. I'm still working on analysing it. There are 500,000 data points from a 2 hour ride! I suspect that there is a power cutoff. Power = torque x cadence, so a high cadence would reach the power limit at a lower torque.

 

[Bad Mechanic]

I didn't think of it in terms of power before, but that makes a lot of sense.

 

[Bigtuna00]

More likely it's protection to prevent the motor from overheating. I've ridden Shimano, Bosch, and Brose extensively and all three limit the power significantly if cadence is too low.

 

[Bad Mechanic]

More likely it's protection to prevent the motor from overheating. I've ridden Shimano, Bosch, and Brose extensively and all three limit the power significantly if cadence is too low.

I'm this case, my cadence was too high.

 

[Bigtuna00]

I'm this case, my cadence was too high.

Ah sorry I misunderstood your post. I've never felt the power cutoff with high cadence, that doesn't sound normal.

 

[aarfeldt]

According to this thread, there can be some high-cadance cut off.
EP8 is not included, but it would propably follow the trend.

 

[Mteam]

I've noticed the assist drop noticeably at high cadence on a bosch gen4, not cut off completely but reduce a lot, it seems to be noticeable from around 105rpm

 

[eMullet]

Its perfectly normal that the assist reduces above 100rpm. The optimal cadence is between 75-95rpm.

 

[B1rdie]

I use this as a battery saving strategy, keep the cadence above 80 rpm. By doing this I can do the same 30km 1.0000 m on trail mode that I used to do on eco mode, working more on the aerobic zone.
this with the old E8000.
Riding on flat terrain I will keep 110-120 rpm to maintain 32km/h speed and at this situation I can feel no drop of assistance in the 80 to 110 rpm range.

 

[iXi]

Can't speak for the ep8 but the e8000 definitely cuts out at a higher cadence 120+.

 

[sendler2112]

Motors naturally have a range of operating rpm depending on the number of turns in the winding. The designer has to choose trade offs between low and high rpm ranges and move the power band to suit. Back EMF eventually impedes the output of all electric motors to zero at some rpm depending on the design choices of power band.
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"The term back electromotive force is also commonly used to refer to the voltage that occurs in electric motors where there is relative motion between the armature and the magnetic field produced by the motor's field coils or permanent magnet field, thus also acting as a generator while running as a motor. "
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Counter-electromotive force - Wikipedia

en.wikipedia.org

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