Bosch CX Gen3 Repair

LimboJim

Well-Known Member
I recently sent my out-of-warranty Gen3 CX in to eBike Motor Repair in TN (EMR) and got a complete overhaul (and then some) for less than half the price of a replacement motor! Want more details? Please read on...

When replacing the chain a couple of years ago on my 2017 Haibike Xduro Allmtn 8.0 (~900 trail miles), I noticed a bit of a rough feel and low growl in the bike's Gen3 CX when I turned the crankarms with the chain off. The motor was just past its warranty period and showed no signs of performance issues, plus I assumed that a new motor would be well over $1k, so I kept riding it to see if any new noises or operational problems developed when in use.

It stayed the same for several hundred more miles (~1300 now), but when I checked another bike's Gen3 CX with its chain off, it was much smoother so I figured I'd been pushing my luck. Starting a few years ago, I'd heard good things about Performance Line Bearings' (PLB's) affordable ebike motor repair service on the eMTB Forums, but they're in the UK and the pandemic seemed to be causing all kinds of overseas shipping issues.

I'd been following PLB as they expanded their part and service offerings to other motor brands (Brose, Yamaha, Panasonic and Impulse). They also made some videos showing how to do it myself - they sell parts and complete overhaul kits, as well - but my DIY aptitude has been limited to bicycle-related stuff. I've also done some minor" plug-n-play" ebike-related stuff (including a gravel DIY build), but opening a motor is beyond my pay grade...

Last month I saw that a USA-based outfit (EMR) partnered with PLB at some point, so I reached out to them. The EMR website's service ticket process was straightforward and simple - fill out the info and follow instructions for sending in your motor. I recommend having a quality local bike shop help with motor removal, packing and shipping if you're uncomfortable with that stage - the job took my rudimentary skills about an hour, so the LBS labor cost should be reasonable.

Two days after I sent my CX motor to EMR, I got a detailed email saying that the cause of my motor's roughness was a damaged "deep gear cluster" (pic below). I lucked out because they'd never seen this before, but happened to have replacement part on-hand. It was also recommended that I have them do a complete overhaul while the motor was "open." A bit more expense for more peace of mind made total sense to me!

The motor came back to me a couple days later (about a week total, back & forth), and is smooth as silk in every way now. The seals EMR used are superior to the factory originals, so I'm confident I'll get at least several more years of eMTBing out of this motor.

@William - Bosch Team - have you seen this "deep gear cluster" armature break before? Again, EMR hadn't seen it before and it didn't cause motor failure, though it was probably just a matter of time because it was apparently flopping around inside the motor housing...
1626459917211.png
 
Last edited:

Edrummer

Active Member
I recently sent my out-of-warranty Gen3 CX in to eBike Motor Repair in TN (EMR) and got a complete overhaul (and then some) for less than half the price of a replacement motor! Want more details? Please read on...

When replacing the chain a couple of years ago on my 2017 Haibike Xduro Allmtn 8.0 (~900 trail miles), I noticed a bit of a rough feel and low growl in the bike's Gen3 CX when I turned the crankarms with the chain off. The motor was just past its warranty period and showed no signs of performance issues, plus I assumed that a new motor would be well over $1k, so I kept riding it to see if any new noises or operational problems developed when in use.

It stayed the same for several hundred more miles (~1300 now), but when I checked another bike's Gen3 CX with its chain off, it was much smoother so I figured I'd been pushing my luck. Starting a few years ago, I'd heard good things about Performance Line Bearings' (PLB's) affordable ebike motor repair service on the eMTB Forums, but they're in the UK and the pandemic seemed to be causing all kinds of overseas shipping issues.

I'd been following PLB as they expanded their part and service offerings to other motor brands (Brose, Yamaha, Panasonic and Impulse). They also made some videos showing how to do it myself - they sell parts and complete overhaul kits, as well - but my DIY aptitude has been limited to bicycle-related stuff. I've also done some minor" plug-n-play" ebike-related stuff (including a gravel DIY build), but opening a motor is beyond my pay grade...

Last month I saw that a USA-based outfit (EMR) partnered with PLB at some point, so I reached out to them. The EMR website's service ticket process was straightforward and simple - fill out the info and follow instructions for sending in your motor. I recommend having a quality local bike shop help with motor removal, packing and shipping if you're uncomfortable with that stage - the job took my rudimentary skills about an hour, so the LBS labor cost should be reasonable.

Two days after I sent my CX motor to EMR, I got a detailed email saying that the cause of my motor's roughness was a damaged "deep gear cluster" (pic below). I lucked out because they'd never seen this before, but happened to have replacement part on-hand. It was also recommended that I have them do a complete overhaul while the motor was "open." A bit more expense for more peace of mind made total sense to me!

The motor came back to me a couple days later (about a week total, back & forth), and is smooth as silk in every way now. The seals EMR used are superior to the factory originals, so I'm confident I'll get at least several more years of eMTBing out of this motor.

@William - Bosch Team - have you seen this "deep gear cluster" armature break before? Again, EMR hadn't seen it before and it didn't cause motor failure, though it was probably just a matter of time because it was apparently flopping around inside the motor housing...
View attachment 93486
I had my Brose motor fully overhauled by EMR. The motor actually performs better now than when it was new. Top notch service!
 

PedalUma

Well-Known Member
Region
USA
Nice. I made a mid-drive torque sensor bike in Feb. of 2018. It has been ridden by a guy, Chip, as a daily commuter. Yesterday I opened the motor and overhauled it. He picked it up an hour ago, test ridding it first and is supper happy. It also got a tune up and drivetrain replacement. I was able to put the derailleur in a ultra-sonic parts cleaner and rebuild it instead of replacing it.