Chris Nolte
Well-Known Member
Chris, first of all thank you for these videos.
My question is do you know what exactly peak and nominal values mean for Bosch motors? Since you communicate with them regularly I am hoping that you have some detailed information. A technical document would be good too if they have any.
Peak can mean many different things, maximum input power that can be drawn from the battery or maximum power output for the motor and in both cases this value is usually only sustainable for very brief periods of time so not very important.
Likewise torque rating makes little sense unless we know what cadence range it is supplied.
I believe nominal powers (250 for CX and 350 for Speed) are outputs that can be sustained "indefinitely"(not really indefinitely but for long periods of time steadily) but in that case did you feel a significant difference when you are riding CX and Speed motors under load? The test may not be straightforward since CX is speed limited. One way to test is to ride both uphill (steep and long enough to keep them at their nominal output).
Bosch doesn’t publish all of these details, but one way you can think of it is based on the percentage of assistance. The peak power on the new CX is 340% so based on the nominal 250W the peak power is actually 850W. The torque is more specific where the max torque is 75Nm and available at the peak power in turbo mode. The torque isn’t based solely on cadence though, you can have full torque at a low cadence.
They do list some of these details under the specifications section of their motors on their website.
Performance Line CX: the highest performance Bosch motor for eMTBs
Best eMTB experience: A powerful drive with unique dynamics and best possible traction on trails, thanks to the Performance Line CX with 85 Nm.
www.bosch-ebike.com