2021 Trek Allant+ 7S: Slight Vibration Emitting from Bosch Performance Speed motor

MrLibraryMan

Member
Region
USA
About a month ago, I became the proud new owner of a Trek Allant+ 7S bike that I really enjoy riding just about every day on smooth surfaced streets in neighborhoods that are sometimes particularly hilly with some steep inclines. This e-bike is a pleasure riding especially since my new Trek bike is a Class 3, which is a vast improvement over my "old" Trek Lift, Class 1 e-bike. To add to the enjoyment of my new bike, I asked my LBS before leaving the store to update the firmware on the motor so that I could take advantage of the new 85Nm feature which I thought would help on the streets' hilly terrain. Well, so I thought...

From time to time I feel a slight, intermittent vibration coming from the Bosch Performance Speed Motor as I travel around 10-15mph (or faster) on level surface streets and on uphill surface streets. At first I thought it was the OEM tires, but discovered that they were not creating/contributing to the problem. It's not from the pedals either. The slightly annoying and irksome vibration is definitely coming from the Bosch motor.

Whenever I feel the subtle vibration from the motor, it tends to lessen or even disappear when I increase the mode from tour to sport or even turbo and while I'm in 3rd, 4th, or 5th gear. So my question is, is this slight and intermittent vibration an unintended indicator or warning that the motor is laboring or that it cannot adequately handle the demands I'm placing on it? Of course, if I am going up a hill, I'll drop to 3rd or 2nd or 1st gear to lessen the demands on the bike (and on me). (By the way, I weigh 215 lbs., and I don't have any heaving loads on the bike other than my Kryptonite New York U-Lock and a small frame bag for bits and pieces.)

I did some research before posting this conversation and discovered a potential reason for the slight vibration: There may be a damping foil omission that supposed to be between the frame and motor and that it may not be installed. Could that be causing the slight vibration or do I have defective Bosch motor? Or is there an adjustment I need to have my LBS tech make? I cleaned the chain, sprockets, and cassette and then oiled those components which gave some improvement, but it did not eliminate the problem (and just made me feel better about doing the maintenance LOL).

On a slightly different topic, since I always travel on smooth streets and often hilly ones, I never treat the bike as a mountain bike and I never pop any wheelies. That said, would there be an advantage to ask my LBS tech to have the eMTB mode turned on my bike?

Thank you all in advance for any suggestions you can offer.

David
 

MrLibraryMan

Member
Region
USA

MrLibraryMan

Member
Region
USA
Any update on your motor?
Thanks for asking, Akrotiri!

With a little more than 1200 miles on my current bike, I have gotten used to what I was finding to be somewhat of an annoyance in the early days of ownership. Before I bought my Trek Allant+ 7S, my first ebike was a Trek Lift+ that had a very smooth, quiet Shimano STEPS motor. No vibrations and no whining like the Bosch Performance Speed Motor on the Allant+ 7S. Even the Allant's derailleur is somewhat clunky in relation to the Lift+'s derailleur. Every tech at my LBS has told me that the Bosch system is louder and will quiet down as time goes on. That might have been so, or what I really think is that the noise and vibration are something I got used to over a period of time. But I sometimes long for the days of having the quiet performance the Shimano motor on my old bike had when I owned it.

(BTW, a tech at Bosch told me that they know that the Performance Speed Motor is noisy but that the Bosch people wanted to keep the motor light in weight which could have been weighed down with more sound silencers.) Anyway, I still really enjoy my Allant+ 7S, but would I ever buy an ebike with a Bosch motor again? Nope.
 

Dallant

Well-Known Member
Region
USA
I’m not sure if my 2020 Allant+7 Bosch CX motor is getting quieter but it’s not getting any louder or having any other noises develop. I’ve since bought 2 other Treks with CX motors. The other (2021) Allant+7 makes a bit less noise and the (2021) Rail 5 is definitely quieter.