Aside from top speed cut-out, are there any other nanny behaviors in the Bosch software?

[Lazy Clydesdale]

(Canyon Strive on cfr)

Sometimes when I am going all out, it seems like the motor backs off temporarily.

Sub-20mph, pedaling through a corner or switchback, it's almost as if the bike assumes I have spun out or laid it down and is maybe trying not to worsen the situation.

It doesn't make sense that it would notice lean angle, maybe a small amount of momentary wheelspin making speed appear higher? That doesnt make a lot of sense either, I thought we are gps-monitored for overspeed?

Happens very rarely, but it is disruptive for a race rig.

Hypotheses?

 

[Shark58]

I thought we are gps-monitored for overspeed

Speed on Bosch motors is monitored by reading the rear wheel revolutions through a magnet/sensor pair and calculating speed from that input. If you are near cut off speed and the rear wheel spins into overspeed this could lead to a drop in support.

 

[Mrj35]

(Canyon Strive on cfr)

Sometimes when I am going all out, it seems like the motor backs off temporarily.

Sub-20mph, pedaling through a corner or switchback, it's almost as if the bike assumes I have spun out or laid it down and is maybe trying not to worsen the situation.

It doesn't make sense that it would notice lean angle, maybe a small amount of momentary wheelspin making speed appear higher? That doesnt make a lot of sense either, I thought we are gps-monitored for overspeed?

Happens very rarely, but it is disruptive for a race rig.

Hypotheses?

pretty similar to shimano as well. sometimes it misinterprets the speed so i stop pedalling for a second then resume and the power is back all the way.

 

[Lazy Clydesdale]

Speed on Bosch motors is monitored by reading the rear wheel revolutions through a magnet/sensor pair and calculating speed from that input. If you are near cut off speed and the rear wheel spins into overspeed this could lead to a drop in support.

Wouldn't that mean we could lower the claimed wheel size in the Flow App to raise the top assist speed? I thought Bosch negated that possibility

 

[Mrj35]

Wouldn't that mean we could lower the claimed wheel size in the Flow App to raise the top assist speed? I thought Bosch negated that possibility

you could but it could also throw a code. I know people that have done that on shimano and it threw an error code eventually. Then your warranty is voided probably not worth it until after the warranty period has passed.

 

[Anders]

Wouldn't that mean we could lower the claimed wheel size in the Flow App to raise the top assist speed? I thought Bosch negated that possibility

I think I once read somewhere that there are two (possibly different) wheel sizes in the Bosch smart system. One is factory set and can't be changed by the user, but possibly by the LBS. The second one we see (and can change) in the app. The first one is used for speed maeasurements. I think the second is just used for the distance travelled in the app.

 

[Shark58]

I think I once read somewhere that there are two (possibly different) wheel sizes in the Bosch smart system.

This is correct and not different to the pre smart motors from Bosch.

In both there are two separate wheel sizes. One is nearly hard coded and can only be changed by the bike manufacturer (with some help from Bosch and a LBS). This value is responsible for the cut off speed.

The second value, identical to the first on delivery, is the one surfaced in the Flow app. A user can change that value, normally within +/- 5% of the original, to adjust the displayed speed to variations in tire size. Any change will also affect the measured ride distance for individual rides in the Flow app statistics.

The overall sum of total distance ridden is calculated by the non changeable value from above and stored in the motor. So after some time these two distance figures will drift apart.