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I don't believe that any make of current crank drive electric motor (DU) as fitted to eMTB's is not going to be susceptible to outer bearing failure, especially if the bike is used in Europen off road conditions.
Excellent Reply Eddie with well-considered and interesting information.
Whether I am a fitter rider or not I tend to only use the lowest eco level of assistance for the majority of the time on my PU Yamaha engine bike and had wondered myself whether the power I add to the pedals is more likely to cause wear to the main bearing than a rider that uses more motor power and less pedal power.
As you say at some point with any DU motor which replaces the bottom bracket of a normal bike the bearing that deals with the forces delivered by the motor and pedals will eventually wear out.
In my case as a high milage commuter this happened at 6000 miles and just after the two-year warranty expired. As with any bearing that wears it had probably been getting worse for some time before my blunt mechanical sympathy was finally made to accept that something was wrong.
I was lucky that the Bike shop I bought from (Ebike shop Farnham) were good enough to replace the motor free of charge in double quick time. Well done to them.
I believe that Yamaha rather than repairing a motor take the view that replacing a motor is easier within the guarantee period. However, the motor still worked properly and it was the bearing that was worn out.
When I reach that point again with the new motor it will be interesting to see whether the shop will advise me that they can replace this bearing or again suggest a new motor.
Maybe manufacturers take a slightly cynical view that the majority of owners will not ride far enough for this bearing to fail within the warranty period.
In this time of unit construction and a throw away attitude to many products etc it may be seen as simply easier to take a motor with a worn bearing out and shove a new motor in.
You would think that a good motor design should have a quality well protected bearing with a good life expectancy and that the design allows for the bearing to be replaced relatively straight forwardly in due course.
Your point about cleaning products potentially effecting the life expectancy of bearings is interesting.
I have known for some time not to use a high-pressure hose as this can force water beyond seals into bearings and cause premature failure of either wheel, bottom bracket, motor or anywhere else
I have used products like muc off and you have made me wonder whether I should stick to just an ordinary hose and chain lube. What products do you recommend for basic washing down a dirty muddy bike?
My own experience of my original Yamaha battery has so far been good.My battery still continues to show little sign of degradation after 2 years and 7 months and 7470 miles.
However, a regular commute to work may be a kinder application for a battery than leisure use as I am never exploring the full extent of the range. I leave my battery indoors after returning from work with usually about a 65% charge and then only charge it back up to 100% just before I set off for work. Again, I have about 65% left when I get to work and can charge it back up before my trip home.
However using the link provided by lzzyekerslike to the Yamaha service manual allowed me to check the health of my battery and perhaps not surprisingly I found that I had charged my battery more than 700 times the maximum measurement available.
However the same service manual allowed me to check in a rather crude way the absolute battery capacity of my battery and it is still showing the highest battery capacity that can be indicated by this test ie 75% to a %100. As a commuter doing a similar milage each day I never find out how the maximum distance my bike can achieve now has been affected by its age and continual use. It does however broadly use the same amount of capacity on my journey too and from work as it always has.
Again perhaps a little cynically you could argue that the above tests allow a shop to refuse to replace a battery within its warranty period as the shop can demonstrate that the battery capacity has not fallen beneath 75% hense that parameter!
Bottom line is that I could not commute to work and back carrying two loaded panniers on an ordinary bike let alone cross country using a selection of xc routes that now include some quite demanding ones.
As I said in the conclusion of my review of my bike after the first 1600 miles of use, “ I am still very impressed with this bike. I think that the combination of the Haibike frame and Japanese motor are a great combination and hard to beat. I have ended up with a highly capable mountain bike and fast road bike that can also lug me and two full panniers around with consummate ease. More importantly than all this is that riding this bike is amazing fun and it has enabled me to commute to work by bicycle and leave the car at home which I could not have done on an ordinary bike. You obviously also get a lot of exercise in a way that you hardly notice.
If anything I am even more impressed now that I have covered over 7500 miles. The basic cost of my bike was £1750, and I am getting a lot of fun out of it.
Perhaps the shops that sell them need to raise their game and be able to much more quickly reliably sort out any problems you get. These bike cost a lot and should have the best quality after sales support. I am not sure that for the majority of people that is the case. Hopefully as more and more are sold competition for business will force shops to become better in this respect. I am grateful that the shop where I bought mine is local to me and has turned out to be exceptionally good at after sales support when I have required it.