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

Dallant

Well-Known Member
Region
USA
Tried to read all comments, but have you taken the chain off and spun the crank with just the motor under power?
Except that leaves any real torque/torque sensor out of the equation so it’s not a true test of the system.(?)
 

Dallant

Well-Known Member
Region
USA
BTW, just getting back on my Allant+7 for longer rides and did 29 miles today. For the first time I noticed the slight vibration the OP was describing. I noticed it come and go while doing a long uphill section in the middle of my ride in Touring and EMTB modes but it certainly wasn’t a troublesome feeling.
Interestingly, I just had the Allant in the local Trek shop yesterday having a new SCHWALBE G-One tire and tube put on for the season. I also had them check/measure my chain and they said it was at .75 so, in their opinion, it (and everything else) seemed fine for now.
 

Alaskan

Well-Known Member
I don't let my chain get more than. 5%. The cassette lasts much longer that way. Worn chain wears the valleys on your cogs. Especially the smaller ones that hold by fewer teeth.
 

Long timer

New Member
Thank you for your timely post. I tested the Allant 7S today. I thought it would be the perfect bike to fit my needs. I loved it....Except, for the same damn vibration you feel when you ride your bike. The bike was assembled this morning, so I have difficulty believing the problem is wear related. By the way, you are not hypersensitive. The vibration is pronounced. I have test ridden several speed pedelecs, some with the same motor and never felt anything like this. I'm passing on this bike because of this issue. I suspect TREK is aware of issue. Hopefully they are working on a fix for you.
 

Alaskan

Well-Known Member
My Trek Allant 9.9s never has had this issue. Perhaps the carbon frame absorbs the vibration.
 

Akrotiri

Well-Known Member
Region
Europe
Thank you for your timely post. I tested the Allant 7S today. I thought it would be the perfect bike to fit my needs. I loved it....Except, for the same damn vibration you feel when you ride your bike. The bike was assembled this morning, so I have difficulty believing the problem is wear related. By the way, you are not hypersensitive. The vibration is pronounced. I have test ridden several speed pedelecs, some with the same motor and never felt anything like this. I'm passing on this bike because of this issue. I suspect TREK is aware of issue. Hopefully they are working on a fix for you.
There is no issue with the motor. It’s a high torque motor and it maximizes the vibration of the chain. I get the same thing in my allant 8s for a year and have had no issues at all with 2300 miles on the odometer.

Furthermore when pedaling hard in high gears at high speed on my analog non-electric bikes I also feel the chain vibrating and traveling to my feet. That is how I am 100% sure of the Bosch motor not having an issue on my allant8s.

Our pedaling produces torque to propel our bikes forward which is energy and it has to travel somewhere and it happens to travel through the chain and we feel it at our feet.
 
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Dallant

Well-Known Member
Region
USA
There is no issue with the motor. It’s a high torque motor and it maximizes the vibration of the chain. I get the same thing in my allant 8s for a year and have had no issues at all with 2300 miles on the odometer.

Furthermore when pedaling hard in high gears at high speed on my analog non-electric bikes I also feel the chain vibrating and traveling to my feet. That is how I am 100% sure of the Bosch motor not having an issue on my allant8s.

Our pedaling produces torque to propel our bikes forward which is energy and it has to travel somewhere and it happens to travel through the chain and we feel it at our feet.
While I haven’t felt this vibration much it is there now and then. Or maybe I just notice it now and then. Either way, I’m over 1300 miles and a years worth of great, problem free performance on every surface and incline from Trek/Bosch PLCX!
 

Alaskan

Well-Known Member
The only times I have felt vibration in the pedals is when I am in one the smallest two cogs on the cassette, pedaling hard, going fast when those cogs have developed wear on them. Those smaller cogs have the chain holding on to them with the fewest teeth and are subject to the greatest wear. This can be triggered by replacement of the chain. Those small cogs typically wear out first. When the chain and the cog have been wearing together, the valleys between the teeth in the cogs get deeper. Replacing the chain can create a mismatch between the new chain and the worn cog. The next sign of even more wear is the chain skipping teeth, usually the time that most people replace their cassettes.

In many cases, especially with Shimano cassettes, you can find individual small cogs available as spare parts. Replacing the smallest individual cogs helps extend the life of the whole cassette making wholesale replacement of the cassette less frequently needed. Obviously the first defense against excessive cog and chain wear is regular cleaning and lubrication a messy but absolutely essential task for maximum smoothness, speed and part life. The other thing we can do that has no cost is to get in the habit of briefly easing up on the pedal pressure during shifts. It is easy to tell if your are doing that correctly as there is way less grinding, clunking and noise during shifts. All that noise is wear and tear on the chain and cogs. While not necessary on a derailleur type drive train it substantially reduces wear.
 

JonP

New Member
Region
New Zealand
i have the same issue with the Trek 2020 Allant7. A horrible vibration as describe, usually at speed and torque and on the downward stroke. Wouldn’t have bought it if I new. I’m waiting on a reply from Trek in NZ as to what is the issue and have linked this “thread” so they see it is a global issue.
Its all new and chain is new and lubed. It you feel it on your bike you will see it’s a vibration coming from the drive train somehow. I though at first it was a physical indication to change up power or gears, but somehow I think it is just plain bad programming. The rest of the travel is smooth as silk until the pedal vibration hits. Interestingly riding up a steep road in Sport at about 20km in a mid range gear it was smooth but as soon as the slope lessoned and the torque wasn’t as hard the vibration kicked in until it got steep again or I changed gears.
If I get any answers I’ll post them. If I can navigate back to this thread.
 
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Alaskan

Well-Known Member
i have the same issue with the Trek 2020 Allant7. A horrible vibration as describe, usually at speed and torque and on the downward stroke. Wouldn’t have bought it if I new. I’m waiting on a reply from Trek in NZ as to what is the issue and have linked this “thread” so they see it is a global issue.
Its all new and chain is new and lubed. It you feel it on your bike you will see it’s a vibration coming from the drive train somehow. I though at first it was a physical indication to change up power or gears, but somehow I think it is just plain bad programming. The rest of the travel is smooth as silk until the pedal vibration hits. Interestingly riding up a steep road in Sport at about 20km in a mid range gear it was smooth but as soon as the slope lessoned and the torque wasn’t as hard the vibration kicked in until it got steep again or I changed gears.
If I get any answers I’ll post them. If I can navigate back to this thread.
Does this only happen in Turbo mode at lower RPMs on relatively level ground? If not what are the specific circumstances under which it occurs?
 

JonP

New Member
Region
New Zealand
i have the same issue with the Trek 2020 Allant7. A horrible vibration as describe, usually at speed and torque and on the downward stroke. Wouldn’t have bought it if I new. I’m waiting on a reply from Trek in NZ as to what is the issue and have linked this “thread” so they see it is a global issue.
Its all new and chain is new and lubed. It you feel it on your bike you will see it’s a vibration coming from the drive train somehow. I though at first it was a physical indication to change up power or gears, but somehow I think it is just plain bad programming. The rest of the travel is smooth as silk until the pedal vibration hits. Interestingly riding up a steep road in Sport at about 20km in a mid range gear it was smooth but as soon as the slope lessoned and the torque wasn’t as hard the vibration kicked in until it got steep again or I changed gears.
If I get any answers I’ll post them. If I can navigate back to this thread.
The vibration occurs in any mode and any gear. It starts when a certain type of speed and torque is reached then will go when you change that by going up a mode/gear/or speed (except when it vibrates at your maximum pedalling speed) then it might go if terrain steepens or declines. It’s consistency is what, to me,indicates that it is programming issue. The regularity of perfectly smooth then vibration then smooth when the sensors feel a specific torque seems to back this theory. Unfortunately due to it to happening in any gear, speed, terrain (except downhill so far) makes it seem random as well as I couldn’t pinpoint that it starts at X gear going X kms on X road surface.
 

Akrotiri

Well-Known Member
Region
Europe
The vibration occurs in any mode and any gear. It starts when a certain type of speed and torque is reached then will go when you change that by going up a mode/gear/or speed (except when it vibrates at your maximum pedalling speed) then it might go if terrain steepens or declines. It’s consistency is what, to me,indicates that it is programming issue. The regularity of perfectly smooth then vibration then smooth when the sensors feel a specific torque seems to back this theory. Unfortunately due to it to happening in any gear, speed, terrain (except downhill so far) makes it seem random as well as I couldn’t pinpoint that it starts at X gear going X kms on X road surface.
From my experience with the Gen 4 Bosch speed and feeling the vibration at the pedals intermittently you have nothing to worry about.

2300 miles and no issues.
 

JonP

New Member
Region
New Zealand
From my experience with the Gen 4 Bosch speed and feeling the vibration at the pedals intermittently you have nothing to worry about.

2300 miles and no issues.
I’m not worried that it is going to stop working, I’m concerned that it has a horrible vibration coming from the pedals to my feet every time I ride it. There must be a specific cause that hopefully can be remedied.
I’d advise people to try one before buying and owners to ask Trek what they plan on doing to get rid of this.
 

Long timer

New Member
The vibration occurs in any mode and any gear. It starts when a certain type of speed and torque is reached then will go when you change that by going up a mode/gear/or speed (except when it vibrates at your maximum pedalling speed) then it might go if terrain steepens or declines. It’s consistency is what, to me,indicates that it is programming issue. The regularity of perfectly smooth then vibration then smooth when the sensors feel a specific torque seems to back this theory. Unfortunately due to it to happening in any gear, speed, terrain (except downhill so far) makes it seem random as well as I couldn’t pinpoint that it starts at X gear going X kms on X road surface.
I only test rode this bike for 30 minutes, but your description fits my experience exactly. While commenters to this post differ on what's causing the vibration, how often the vibration occurs or how much it annoys them, it appears the problem is widespread. Quite frankly, I don't care what the exact cause is, only that the problem is there (on a brand new bike) and it should not be. I hope TREK acknowledges this problem and addresses it soon.
 

JonP

New Member
Region
New Zealand
I only test rode this bike for 30 minutes, but your description fits my experience exactly. While commenters to this post differ on what's causing the vibration, how often the vibration occurs or how much it annoys them, it appears the problem is widespread. Quite frankly, I don't care what the exact cause is, only that the problem is there (on a brand new bike) and it should not be. I hope TREK acknowledges this problem and addresses it soon.
Well said!
Unfortunately due to low stock issues here the options for a different brand replacement with the same features are slim to non existent. Giant has one I’d try but it has a hard front and id miss the suspension.
I really hope Trek get back to me and offer hope for a fix or maybe that it is a wearing in issue. Failing that I’ll either return it, or get used to it, or just be bitter with the injustice of my 1st world problem 🤣.
 

Akrotiri

Well-Known Member
Region
Europe
I only test rode this bike for 30 minutes, but your description fits my experience exactly. While commenters to this post differ on what's causing the vibration, how often the vibration occurs or how much it annoys them, it appears the problem is widespread. Quite frankly, I don't care what the exact cause is, only that the problem is there (on a brand new bike) and it should not be. I hope TREK acknowledges this problem and addresses it soon.
It’s not a problem imo so there’s nothing for trek or Bosch to address.
 

Alaskan

Well-Known Member
I would try more frequent cleaning of the chain and cassette as well as adequate and regular lubrication. You might try a different lube that better suits your riding circumstances.
 

JonP

New Member
Region
New Zealand
I only test rode this bike for 30 minutes, but your description fits my experience exactly. While commenters to this post differ on what's causing the vibration, how often the vibration occurs or how much it annoys them, it appears the problem is widespread. Quite frankly, I don't care what the exact cause is, only that the problem is there (on a brand new bike) and it should not be. I hope TREK acknowledges this problem and addresses it soon.
More data- downhill in top gear & touring mode going full tit around 45-50 kms. Vibrations through pedalS bigtime.
Then on the flat in Sport going full tilt pedalling at around 45kms bad vibration, then head wind hit and slowEd me to 35. This increase of torque immediately stopped vibration. Spent rest of commute tested gears, modes & turning motor off while riding.
Summary, the increase of resistance seems to decrease or remove the vibration, but on a bike that is designed to go fast and you have good air & road conditions you will get major vibrations at speed.
So if you ride like an old nana then no problem, buy one. Unfortunately after 46 yrs motorcycling I feel the need for speed 🙃
 
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