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

MrLibraryMan

New 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, 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

P.S. I hope I'm permitted to have this post on both the Trek Forum and on this Bosch Forum.
 

William - Bosch Team

Active Member
Hi David,

Congrats on the new bike! 🥳

Noises, vibration, etc., are quite difficult to diagnose remotely, as you might imagine.

The best advice I can give is to take your bike back to the place of purchase, and get it looked at by their trained mechanic. Whether it's an issue with the eBike system, or some other part of the drive train, you will need the shop for a resolution. Most shops include some period of free service as part of a new bike purchase. The damping foil omission you referenced relates more to creaking under load, rather than transmission of vibrations from drive unit to frame.

Without riding your bike myself, it's difficult for me to gauge the severity and/or source of the vibration, hence the importance of having your shop take a look. That being said, I'll throw a few thoughts out there...

- It could be vibration in the chain that only happens at certain cadences, and with specific amounts of torque applied. I noticed this on my own Bosch-equipped eBike yesterday while riding around 15 mph (different drive unit than yours), and I've noticed it numerous times throughout the years while riding my own non-eBikes, and working on customer's non-eBikes as a shop mechanic. Lubrication tends to lessen this, as it dampens the action of the chain (my single-speed, non-E mountain bike gets a brutal vibration in the chain when I don't lube it often enough. It feels especially awful when spinning at high-cadence and lower torque. I can feel it in my legs, etc.) In any case, this theory is supported by the lessening/disappearance you experience when changing to a higher assistance mode as the increased torque pulls the chain harder and lessens potential for vibration. (without riding your bike myself, I'd say my money is on this)

- It could be an issue with your Bosch drive unit. If so, the shop should be able to diagnose this, and get you a warranty replacement from Bosch.

- Your cadence may be too low. I'm not 100% clear on what gear you are riding in, but you did mention dropping all the way to 1st. So that we are on the same page, is 1st gear for you the largest diameter cog in the back, closest to your spokes? If that is correct, then probably not this, but FYI: Bosch recommends at least 50 RPM for your pedaling.

- It could be a slightly out-of-adjustment drive train. All new bikes will experience a drive train break-in period and require adjustment in the first month or so.

- Maybe your drive unit mounting bolts need to be re-torqued. Your shop should call Bosch Service first if they've never done this before, as there are several different things to consider and check.

- It could be something completely different, as noises/vibrations are notorious for "showing themselves" far from their source.

Let us know what you find out!
 

Akrotiri

Well-Known Member
Region
Europe
Inth
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, 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

P.S. I hope I'm permitted to have this post on both the Trek Forum and on this Bosch Forum.
I think William hit it spot on and it’s likely coming from somewhere else and most likely a vibrating chain.

I doubt it’s coming from the motor because if the motor were failing it would invariably be accompanied by an unusual and ominous soul crushing noise. You didn’t mention hearing any unusual noises (except for the standard Bosch whirring) coming from the motor; just vibrations at certain cadences, correct?

I should add that I too get the vibration that I feel in my feet while pedaling from time to time. Always at the very beginning or very end of my rides. Initially, like you I thought it was coming from the motor but noises and vibrations notoriously travel on bicycles and e-bikes. I self-diagnosed it as coming from my chain many moons ago.
 
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MrLibraryMan

New Member
Region
USA
Hi David,

Congrats on the new bike! 🥳

Noises, vibration, etc., are quite difficult to diagnose remotely, as you might imagine.

The best advice I can give is to take your bike back to the place of purchase, and get it looked at by their trained mechanic. Whether it's an issue with the eBike system, or some other part of the drive train, you will need the shop for a resolution. Most shops include some period of free service as part of a new bike purchase. The damping foil omission you referenced relates more to creaking under load, rather than transmission of vibrations from drive unit to frame.

Without riding your bike myself, it's difficult for me to gauge the severity and/or source of the vibration, hence the importance of having your shop take a look. That being said, I'll throw a few thoughts out there...

- It could be vibration in the chain that only happens at certain cadences, and with specific amounts of torque applied. I noticed this on my own Bosch-equipped eBike yesterday while riding around 15 mph (different drive unit than yours), and I've noticed it numerous times throughout the years while riding my own non-eBikes, and working on customer's non-eBikes as a shop mechanic. Lubrication tends to lessen this, as it dampens the action of the chain (my single-speed, non-E mountain bike gets a brutal vibration in the chain when I don't lube it often enough. It feels especially awful when spinning at high-cadence and lower torque. I can feel it in my legs, etc.) In any case, this theory is supported by the lessening/disappearance you experience when changing to a higher assistance mode as the increased torque pulls the chain harder and lessens potential for vibration. (without riding your bike myself, I'd say my money is on this)

- It could be an issue with your Bosch drive unit. If so, the shop should be able to diagnose this, and get you a warranty replacement from Bosch.

- Your cadence may be too low. I'm not 100% clear on what gear you are riding in, but you did mention dropping all the way to 1st. So that we are on the same page, is 1st gear for you the largest diameter cog in the back, closest to your spokes? If that is correct, then probably not this, but FYI: Bosch recommends at least 50 RPM for your pedaling.

- It could be a slightly out-of-adjustment drive train. All new bikes will experience a drive train break-in period and require adjustment in the first month or so.

- Maybe your drive unit mounting bolts need to be re-torqued. Your shop should call Bosch Service first if they've never done this before, as there are several different things to consider and check.

- It could be something completely different, as noises/vibrations are notorious for "showing themselves" far from their source.

Let us know what you find out!
William, thank you very much for replying and with in-depth possibilities! I really appreciate your time to diagnose the problem from afar!

After riding my Trek Allant more since my posting, I became hyper-sensitive to what the symptoms are and where they may be coming from. After reading your reply, I have a sneaking suspicion that it is chain vibration-- everything you suspected in your first point. It happens only during certain cadences and at various amounts of torque I apply to the chain. After cleaning the chain last week with WD-40 Bike Chain Cleaner & Degreaser and then lubricating it with Dumonde Tech Lite Formula Bicycle Chain Lubricant, I found that some of the vibration was reduced during my rides. I guess I should add more of this lubricant, or maybe look for another lube such as Silca Super Secret Chain Lube. The special polymers seem to be needed to quiet the mild vibrations during some cadences.

I also wonder if the eMTB mode would help eliminate or at least quell the chain vibration. What are your thoughts?

Yesterday I brought my bike back to my Trek LBS to have three employees (a Bosch tech and two other employees there) to try to figure out what the vibrations are. They felt that it was a normal vibration and nothing out of the ordinary. Now I've owned a number of bikes and two electric Trek bikes in my 60+ years, and I've never experienced this mildly annoying vibration in the chain. So when they told me that the vibration was nothing out of the ordinary, I was puzzled and a bit frustrated. They also suggested the Silca Super Secret Lube that they're experiementing with with their own bikes. Hmmm. Maybe this could be the magic solution? Have you ever tried this stuff?

Anyway, thank you again, William for your tele-diagnoses! I really do appreciate them!

David
 

MrLibraryMan

New Member
Region
USA
Inth

I think William hit it spot on and it’s likely coming from somewhere else and most likely a vibrating chain.

I doubt it’s coming from the motor because if the motor were failing it would invariably be accompanied by an unusual and ominous soul crushing noise. You didn’t mention hearing any unusual noises (except for the standard Bosch whirring) coming from the motor; just vibrations at certain cadences, correct?

I should add that I too get the vibration that I feel in my feet while pedaling from time to time. Always at the very beginning or very end of my rides. Initially, like you I thought it was coming from the motor but noises and vibrations notoriously travel on bicycles and e-bikes. I self-diagnosed it as coming from my chain many moons ago.
Thank you, Akrotiri, for your posting. Please read what I wrote to William above. Maybe I'm too sensitive to the vibration of the chain, but darn it, with a big chunk of money invested in this bike, it should ride like butter. Anyway, thanks for your input!

David
 

Dallant

Well-Known Member
So why is it you don’t insist your Trek dealer do a diagnostic reading if you are worried it’s the motor?
BTW, these aren’t Cadillacs and vibrations are pretty normal.
 

William - Bosch Team

Active Member
William, thank you very much for replying and with in-depth possibilities! I really appreciate your time to diagnose the problem from afar!

After riding my Trek Allant more since my posting, I became hyper-sensitive to what the symptoms are and where they may be coming from. After reading your reply, I have a sneaking suspicion that it is chain vibration-- everything you suspected in your first point. It happens only during certain cadences and at various amounts of torque I apply to the chain. After cleaning the chain last week with WD-40 Bike Chain Cleaner & Degreaser and then lubricating it with Dumonde Tech Lite Formula Bicycle Chain Lubricant, I found that some of the vibration was reduced during my rides. I guess I should add more of this lubricant, or maybe look for another lube such as Silca Super Secret Chain Lube. The special polymers seem to be needed to quiet the mild vibrations during some cadences.

I also wonder if the eMTB mode would help eliminate or at least quell the chain vibration. What are your thoughts?

Yesterday I brought my bike back to my Trek LBS to have three employees (a Bosch tech and two other employees there) to try to figure out what the vibrations are. They felt that it was a normal vibration and nothing out of the ordinary. Now I've owned a number of bikes and two electric Trek bikes in my 60+ years, and I've never experienced this mildly annoying vibration in the chain. So when they told me that the vibration was nothing out of the ordinary, I was puzzled and a bit frustrated. They also suggested the Silca Super Secret Lube that they're experiementing with with their own bikes. Hmmm. Maybe this could be the magic solution? Have you ever tried this stuff?

Anyway, thank you again, William for your tele-diagnoses! I really do appreciate them!

David
Happy to help!

I hadn't really thought about eMTB reducing chain vibration, but I suppose that makes sense as it tends to require more rider torque input. That being said, I'm not sure how much it will affect it in practice. I'm also not positive that eMTB mode is an option on the Allant+ models, unless someone can confirm it. Only way to know for sure is have shop perform software update, and see if it pops-up as an option.

In terms of the lube you mentioned, I've not tried it. I've been on T-9 Boeshield for many years now. 75% of my personal criteria for lube selection is that I can't even tell it's there. In other words it lubes chain, but is very minimal and picks up no visible dust or dirt. It does not seem to keep things extra quiet though. This is just my personal preference for where/how I ride.

I have some of my own personal demons involving rogue noises. I'll say that every car dealer I've ever purchased from probably does not like me due to my insistence on diagnosis of random noises. That being said, once I know what it is my view changes some- ie: as-designed is generally OK, but defect is not OK.

For bikes... chain vibration never really bothered me because I knew what was happening, BUT suspension linkage creaks, suspension fork bushing clicks, headset creak, seat post creak, derailleur clicks, bb creak, and occasional disc/pad contact all drive me nuts!

You may find some differences among various chain manufacturers. I have some friends that prefer the smooth, quiet characteristics of brand-X vs. brand-Y, while others prefer the longer service life/durability/reliability of brand-A vs. brand-B. The chains I've been using for 6-7 years now are regarded as being some of the noisiest on the market, but I've never had a durability issue. All personal preference.
 

Akrotiri

Well-Known Member
Region
Europe
Thank you, Akrotiri, for your posting. Please read what I wrote to William above. Maybe I'm too sensitive to the vibration of the chain, but darn it, with a big chunk of money invested in this bike, it should ride like butter. Anyway, thanks for your input!

David
You’re welcome.

If you go back in my post history about 9-10 months ago I complained about the exact same issue/observation that you have in this thread. I got the same answers that it was chain vibration. 2000 miles later my only complaint is that my headlight gets too warm lol.

So no worries, just don’t inadvertently submerge the motor in water or jet wash it and avoid pedal strikes at all costs. Your motor will last at-least 10k miles.

Keep calm and Ride on!
 

Dallant

Well-Known Member
Happy to help!

I hadn't really thought about eMTB reducing chain vibration, but I suppose that makes sense as it tends to require more rider torque input. That being said, I'm not sure how much it will affect it in practice. I'm also not positive that eMTB mode is an option on the Allant+ models, unless someone can confirm it. Only way to know for sure is have shop perform software update, and see if it pops-up as an option.
EMTB mode is indeed an option and was installed on my Allant+7 last summer. Supposedly, its an option on any CX. I love it and use it often when going uphill on paved or ground.
 

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William - Bosch Team

Active Member
EMTB mode is indeed an option and was installed on my Allant+7 last summer. Supposedly, its an option on any CX. I love it and use it often when going uphill on paved or ground.
Ah yes! I forget that the Allant has the CX DU option. I was thinking only of the Performance Speed. Thank you!


You are correct, should be an option on any CX unless the OEM specifically decides not to allow it.
 

Dallant

Well-Known Member
Ah yes! I forget that the Allant has the CX DU option. I was thinking only of the Performance Speed. Thank you!


You are correct, should be an option on any CX unless the OEM specifically decides not to allow it.
The Trek shop that did the Bosch update said it was the first they had done and they were surprised that EMTB was an option for the Allant. It was not my local shop and I asked them to do it while they were repairing a flat for me.
 

MrLibraryMan

New Member
Region
USA
EMTB mode is indeed an option and was installed on my Allant+7 last summer. Supposedly, its an option on any CX. I love it and use it often when going uphill on paved or ground.
When I inquired about that feature, my LBS tech felt that it’s not going to be a benefit to me since I wouldn’t be using it on hilly trails, even though we have lots hills in many neighborhoods. Nevertheless, I’m still intrigued about the EMTB mode. Does it take the place of the sport mode? Does it perform differently than the sport mode or any other mode on hills? How does the EMTB mode help you on paved hills?
 

William - Bosch Team

Active Member
When I inquired about that feature, my LBS tech felt that it’s not going to be a benefit to me since I wouldn’t be using it on hilly trails, even though we have lots hills in many neighborhoods. Nevertheless, I’m still intrigued about the EMTB mode. Does it take the place of the sport mode? Does it perform differently than the sport mode or any other mode on hills? How does the EMTB mode help you on paved hills?
Yes, it replaces Sport mode.

eMTB mode is less about hills specifically, and more about adapting to varied terrain. I sometimes use it when cruising around my neighborhood. When soft-pedaling... it gives me minimal support. When I really need to move, or get clear of a car, etc... I can get on the pedals hard and have up to Turbo level of support.

Remember... it replaces Sport, but gives you anywhere from Tour to Turbo levels of assistance.
 
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Dallant

Well-Known Member
When I inquired about that feature, my LBS tech felt that it’s not going to be a benefit to me since I wouldn’t be using it on hilly trails, even though we have lots hills in many neighborhoods. Nevertheless, I’m still intrigued about the EMTB mode. Does it take the place of the sport mode? Does it perform differently than the sport mode or any other mode on hills? How does the EMTB mode help you on paved hills?
Very different from Sport mode as noted by William above. And if you should want to climb a hilly trail/grassy field, it’s awesome. And it doesn’t appear to negatively affect battery life. I am curious if one could return to Sport if desired.
 

Alaskan

Well-Known Member
How many miles on your chain and your cassette? How often have you cleaned and lubricated your chain? What kind of riding have you been doing?

My experience with the kind of vibration you are describing that you can feel through your feet and occurs in the higher gears at higher speeds is that this is a problem with a chain that needs replacing or a cassette and most likely both. If the chain has been left on beyond .5% stretch it wears and opens up the arcs between the teeth on the smallest cogs on your rear cassette. Riding in dirt and sand a lot, even with rigorous cleaning and lubrication will shorten chain and cog life due to particulate abrasion.

I find I can double the life of my cassette by replacing the two smallest cogs rather than the whole thing. The smallest cogs are your fastest gears that have the fewest teeth engaging the chain and are therefor subject to greater wear. The combination of worn chain and worn cogs allows some miniscule slippage in the the way the cogs engage. Eventually the next step will be chain skipping cogs.

If your chain has more than 1,000 miles and/or your cassette has more than 1500 miles, and if your chain measures more than .5% wear that replacing them could well eliminate your vibration.
 

Alaskan

Well-Known Member
Very different from Sport mode as noted by William above. And if you should want to climb a hilly trail/grassy field, it’s awesome. And it doesn’t appear to negatively affect battery life. I am curious if one could return to Sport if desired.
I don't do technical trails or downhill mountain biking. Thus, I really prefer Sport to EMTB mode as it allows me to select the a narrowly defined assist mode and better control my electron expenditure, giving me a few more miles of range.
 

William - Bosch Team

Active Member
Very different from Sport mode as noted by William above. And if you should want to climb a hilly trail/grassy field, it’s awesome. And it doesn’t appear to negatively affect battery life. I am curious if one could return to Sport if desired.
You can definitely return to Sport mode... shop would perform another software update, and select the "Sport Mode" container file, rather than the "eMTB Mode" container file. I may or may not do this on my pavement bike... can't decide if I like eMTB or Sport better for paved cruising.

You are spot-on with battery life as well. For the Gen4 CX drive unit, Sport mode is 240% on top of what you are doing. eMTB mode is 140-340%, so it's likely that you spend a fair amount of time getting support below that 240% mark, resulting in better-than-Sport mode efficiency. If someone were to ride eMTB very aggressively up steeper terrain, it's likely they might be above that 240% support mark more often, resulting in less-than-Sport mode range numbers.
 

Dallant

Well-Known Member
I don't do technical trails or downhill mountain biking. Thus, I really prefer Sport to EMTB mode as it allows me to select the a narrowly defined assist mode and better control my electron expenditure, giving me a few more miles of range.
I don’t do them either. Not sure why anyone doing downhill would need EMTB mode but for my hilly area, I prefer it over Sport. I haven’t noticed any battery issues but I’ve never had to eek the last little electron out of my battery.😉
 

Stefan Mikes

Well-Known Member
Region
Europe
City
Brwinów (PL)
Tried to read all comments, but have you taken the chain off and spun the crank with just the motor under power?
True scientific approach!
Many newbies claim mid-drive motor creates big resistance unpowered. I recommend to them to remove the chain and just spin the cranks....