Barchettaman

Is it necessary to service the Bosch CX mid motor, or is it just a nice little earner for the dealers?

What if anything do they do to the motor in the service?

I do all the basic drivetrain stuff for my 2017 Cube Reaction e-bike, that‘s easy, but was wondering what if anything the motor needed.

unterhausen

I imagine they eventually need clean and lube

MarcusT

Do it, especially if under warranty.
Bearings, and seals may wear out, cleaning any gunk that may have snuck in there as well.
Spending a few now, may avoid spending hundreds further on.
Just make sure they are doing a physical service. Some shops are lazy and just hook up the computer. If they see no errors, then they don't touch it.

Buglady

I'm a Bosch certified tech. The main thing we do with the drive systems is update the software - there are continual improvements in things like battery management and torque sensing, so updating the software gives you better performance. The onboard software can also (like any computerised system) accumulate errors and random glitches, which is also corrected by a software update. You do have to have this done at a certified shop because the software is proprietary; part of the service is that if there IS a deeply rooted problem, we can call Bosch technical support and they can remote into the system to run really detailed diagnostics. This is part of their warranty protection.

Physically the main thing is that the seals around the drive unit may need to be replaced if they have degraded over time; this will depend heavily on the weather conditions in your area, and the way the drive unit is mounted in the frame. Some have full flange seals and some do not.

Drive train components like the chain and cassette are the same as any other bicycle, so of course you can do those on your own. The chainring on a lot of Bosch drive units is different than standard, and requires a specific tool to remove and replace, but the newer Active Line drive unit uses a lockring that is the same 8-spline pattern as some bottom brackets.

If the drive unit develops a major fault, the fix is often to replace the unit as a whole. People often find this strange, because they think "well, I would not replace my car's engine if that failed!" - but pedal-assist electric motors are not like car engines. They are much more like a component such as an alternator, or power steering unit, that would be replaced as a whole if they failed in your car.

Hopefully this makes sense and helps you understand where your shop is coming from! Enjoy your ride!

Barchettaman

Many thanks for such a detailed reply!

Buglady

You are most welcome! You kind of hit the "autistic special interest info dump" jackpot there