Bosch ebike motor reliability

[Energizer Bunny]

Image of gears as removed from drive unit, still attached to plate. These gears lift off, slight tap required.

 

[Dave_the_B]

Thanks for the instructions...looks like i'm going to be doing this in the not too distance future.
One little question: what grease should I use on the metal gears?
many thanks

 

[Energizer Bunny]

Thanks for the instructions...looks like i'm going to be doing this in the not too distance future.
One little question: what grease should I use on the metal gears?
many thanks

On mine i did not add extra grease to the metal gears, the gears left in the motor seemed very clean. Where there was a dob of grease on one of the nylon gears and it was very tacky when rotating by hand. I did use silicone grease on the bearing, and when re-assembling the bearing seal.

My motor rotates ok now, it is still stiff compared to a standard bike bb, but much better than before. It seems quieter with a longer range to boot.

btw I did this because I had no other choice, I did not ask a bike shop. Although from what I have seen, Bosch are only interested in warranting motors as complete drive units and are not really supporting secondary market.

Knowing what I know now I would not buy another Bosch either new or second hand. My experience of buying bits of manual bikes on ebay and building them up doesn't fit with ebikes. Despite the massive costs they seem to be disposable if they go wrong, hardly environmentally friendly.

 

[Dave_the_B]

On mine i did not add extra grease to the metal gears, the gears left in the motor seemed very clean. Where there was a dob of grease on one of the nylon gears and it was very tacky when rotating by hand. I did use silicone grease on the bearing, and when re-assembling the bearing seal.

My motor rotates ok now, it is still stiff compared to a standard bike bb, but much better than before. It seems quieter with a longer range to boot.

btw I did this because I had no other choice, I did not ask a bike shop. Although from what I have seen, Bosch are only interested in warranting motors as complete drive units and are not really supporting secondary market.

Knowing what I know now I would not buy another Bosch either new or second hand. My experience of buying bits of manual bikes on ebay and building them up doesn't fit with ebikes. Despite the massive costs they seem to be disposal if the go wrong, hardly environmentally friendly.

Thanks for the reply.
My motor is now disassembled on the bench, thanks to your instructions, and waiting delivery of a bearing.

 

[Trevormonty]

Let us know how get on.

 

[Trevormonty]

Knowing what I know now I would not buy another Bosch either new or second hand. My experience of buying bits of manual bikes on ebay and building them up doesn't fit with ebikes. Despite the massive costs they seem to be disposable if they go wrong, hardly environmentally friendly.

I don't think any of other middrive motors ie Shimano Yamaha Brose are any different for out of warranty support. Exchange faulty motor for refurbished motor for big $$. None of their bearings especially on MTBs will last for ever. Being able to replace bearing yourself is big plus.

 

[Energizer Bunny]

I don't think any of other middrive motors ie Shimano Yamaha Brose are any different for out of warranty support. Exchange faulty motor for refurbished motor for big $$. None of their bearings especially on MTBs will last for ever. Being able to replace bearing yourself is big plus.

I guess you right, but the salesman isn't going to highlight these issues which could mean that your £6000 purchase cannot be ridden or repaired in 2 years time, once the warranty period ends. You may be able to sell off the components to recoup some of the money, or if you are lucky you can buy a second hand e-bike and swap over the drive unit. Which might not work as it could have unmatched software coding.

This thread and my experience have been quite sobering.

However I am not sure which will win, my ebike etched Joker grin, or my nervous about reliability frown.

 

[soundwave]

you can buy new motors for about 700 quid but bosch wants the old motor back first b4 they will sell you one.

so finding parts other than bearings is next to impossible.

 

[Dave_the_B]

Energizer Bunny: thanks for the instructions
Bearing fitted and motor nice a quiet now.
Painless from start to finish..

 

[wheeliepete]

Glad to hear you are back on the road Dave.

 

[Ballynoes]

Nice to hear its possible and not too difficult..

 

[Energizer Bunny]

Energizer Bunny: thanks for the instructions
Bearing fitted and motor nice a quiet now.
Painless from start to finish..

Great to hear that.

It is a leap of faith, but ok if you take your time.

Was there much dirt inside your motor?

 

[Dave_the_B]

Completely clean and dry inside..it's my wifes bike so hasn't seen too much mud, my MTB on the other hand sounded like a chainsaw it was so noisy, might have something to do with 12" deep puddles and Dorset clay
I got that motor replaced under warrant but would of liked to have seen inside just for interest.
Next time I have to do a drive bearing I will strip the whole motor out just to see what's what

 

[Andy Elliott]

This has all been really interesting to read. I've had my haibike with Bosch motor for 3.5yrs now and use it for commuting 20miles a day in all weather's. I also spend 4miles of that on the seafront which means sand....a bikes worst nightmare. I'm pretty good at keeping it clean / lubed (no pressure hose) but I'm certainly not perfect.
My BB had a bit of play so my local bike shop contacted Bosch who said replace the motor. However, I then contacted e-bike in Farnham where I had bought it and they were happy to replace the bearing. When he had finished, he showed me the remnants of the old bearing...totally shredded. He said it was the worst he'd ever seen!
The replacement has the plastic protector so hopefully this will give it a bit more protection in the future.
However, after seeing these posts, particularly energiserbunny, if I need to replace the bearing again, I might have a go myself.
Overall, I still love the Bosch drive and it makes my commute effortless. However, I have been suprised by the maintenance costs of the bike, chains, sprokets and cassettes that get eaten by the extra torque. I'm still trying to find the prefect option....cheaper parts that I replace more often or expensive parts that last a bit longer. Latest attempt is the connex ebike chain and the 20tooth sproket to hopefully save the 11tooth on the cassette getting trashed after 3months..let's see how that gets on...

 

[RobF]

I still don't get how crank drives are supposed to wear transmissions.

For most of us - certainly for me - the total load of me and motor on the transmission is less than a fit road cyclist.

Bosch ebikes with hub gears don't eat chains or hubs, so are a better prospect for commuting.

A lot of people buy a mountain bike as commuter then set about changing it to the trekking bike they should have bought by putting on road tyres, mudguards, carriers, lights, etc.

 

[zakventis]

A lot of people buy a mountain bike as commuter then set about changing it to the trekking bike they should have bought by putting on road tyres, mudguards, carriers, lights, etc.[Unquote]

I must confess to doing exactly that! Powerfly7 (which HAS got the plastic protector seal - hence the 4,000 miles and no bearing play at all) - mudguards, carrier, panniers and lights. But the tyres I opted for are Marathon GT365s I got from RoseBikes, Germany, because you can't get the 2" version in the UK. Brilliant on tarmac, they are also great off-road in all but squitty mud!

On the subject of wearing things out, I have just replaced the miniscule rotor-side bearing on the back wheel - a Formula hub! I'm also on my second 16T Connex and 3rd chain but the original Shimano 11-42 cassette looks good for a lot more miles.

 

[Andy Elliott]

I still don't get how crank drives are supposed to wear transmissions.

For most of us - certainly for me - the total load of me and motor on the transmission is less than a fit road cyclist.

Bosch ebikes with hub gears don't eat chains or hubs, so are a better prospect for commuting.

A lot of people buy a mountain bike as commuter then set about changing it to the trekking bike they should have bought by putting on road tyres, mudguards, carriers, lights, etc.

I have to disagree. The logic in my head says that for a road cyclist, pulling away from stationary will put the same load into the pedal as I do. However, the road cyclist is doing that on a 50ish tooth sproket and I'm doing it on 18. Surely this puts more strain on my chain = faster stretching of chain = faster degradation on cassette and sproket.
When I got my bike, I went for the hard nine so that it was good for commuting but also good off-road. The other option was the trekking version....similar price but ultimately I chose the hardnine. Since getting the bike, I have slimmed down the tyres a little but would buying the trekking version meant my components lasted longer? I can't see how it would.
Genuinely interested in others views. It's been a big learning curve over the last 3yrs and I'm still learning!


Sent from my Pixel using Tapatalk

 

[flecc]

I still don't get how crank drives are supposed to wear transmissions.

For most of us - certainly for me - the total load of me and motor on the transmission is less than a fit road cyclist.

Two observations. First up to 500 watts of motor plus 300 watts of average fit rider through acceleration from a standstill is very much more than most averagely fit cyclists will put in then.

Second the very light bikes that the fittest riders use take much less effort to accelerate than a heavy e-bike, so are easier on the transmission.
.

 

[Trevormonty]

When road riding I spend a lot of time between 2 gears around 20-26km/h. This greatly increases wear rate of these gears, their low teeth count doesn 't help. With normal bike my riding would be spread across lot more gears as there is no motor to help with hills.

IGH is probably best option for road riding as it doesn't mind spending most of its time in 1 or 2 gears. Chains and sprockets last longer plus they are cheap.

With MTB motors only IGH options are Nuvinci and Rolhoff. Lower 50nm midrives can use shimano nexus or alfine 8spd. Heard mix stories about alfine 11spd reliability, especially with ebike.

 

[Deleted member 4366]

I still don't get how crank drives are supposed to wear transmissions.

For most of us - certainly for me - the total load of me and motor on the transmission is less than a fit road cyclist.

Bosch ebikes with hub gears don't eat chains or hubs, so are a better prospect for commuting.

A lot of people buy a mountain bike as commuter then set about changing it to the trekking bike they should have bought by putting on road tyres, mudguards, carriers, lights, etc.

The maximum torque multiplication from your average crank drive bike is four times what the rider inputs. That's added to what the ride does, so the end result is 500% of what the drive components would normally get. Wear isn't linear with force, it's exponential, so 500% more force could make 1000% more wear.

Yes, if you turn the power right down, so that the motor is giving hardly any assistance, the wear will be much less; however, it can never be as low as an unassisted bike because an electric bike is heavier, so even if you turned the power down to zero, you'd have to pedal harder than an unassisted bike and the forces would therefore be higher.

None of this can compare with a hub-motored bike, where the torque from the motor reduces the forces on the drive train, which is why it tends to last longer than they would on an unassisted bike.