My bottom bracket torque sensors keep on failing at around 2500-3000km

[Renzo]

I have a lankeleisi mg600 plus 2024 model eFat and I have been having issues with its torque sensor. For whatever reason the torque sensor seems to break within 2500-3000km of cycling and it does not seem to matter if I ride during winter or summer, as the first torque sensor broke during winter and I replaced it with another one that broke during a dry and hot summer, or more precisely, this week.

This is how the thing looks like:


When the sensor breaks, it starts behaving completely random, the assist level fluctuates or it might even drop assist power to something like 5-10% from maximum. I was taking a video for "buybestgear" and "lankeleisi-eu" and I had already sent the video, when I noticed something that happened during the video. There is black dust-like particles falling from the sensor when I rotate it, I took a screenshot of it and marked the area where the dust is falling from and how one can see some of it already fallen on the wooden surface below the sensor. On further inspection, the dust is actually very small metallic flakes that shine under a flash light.

Here is the image:


I am really clueless to this, why on earth is this happening? I don't see any external problems like dust or moisture or corrosion on the sensor, it is quite well hidden from all of that and even the sensor cable hole is located inside the "bottom bracket box" that contains wiring and the controller, hidden from the outside world.

I am obviously out of warranty since bestbuygear and lankeleisi offer only 1 year warranty, even if I live in the EU area and they have warehouses in the EU area. Having said that, I am fine buying a new part if it's not overly costly, but if it is the same crap I already have I simply do not want to try my luck if the third sensor lasts longer than what the two before it did.

I have had the bicycle since september 2024 and it has very close to 6000km in the odometer and like I said, it has destroyed two of these sensors already.

 

[stancecoke]

I have been having issues with its torque sensor

This seems to be a KCLamber product:

Bottom Bracket Torque Sensor TORG2B-Kclamber Electric Technology Corp

Bottom Bracket Torque Sensor TORG2B ●Rated voltage: 5V<br /> ●Output voltage (DCV): 0.7~4.8V <br /> ●ZTV Initial voltage: 0.7±0.1V<br /> ●Torque signal Resolution 32/36<br />

en.kclamberele.com

All of this bottom bracket torquesensors are known for not being reliable. Sempu, ERider...
There are some reports from users of the Cycle Analyst, that grounding the sensor GND to the bike frame helps somehow.

 

[Renzo]

Is there anything that matches those dimensions I measured and that would be reliable and not horrible trash?

 

[amberwolf]

If there is metallic dust, something is wearing inside. If you're willing to open up one of the failed units, it might be possible to correct the problem with a different part if it's something commercially available.

Additionally, if the sensor itself is magnetic in nature, and the dust is magnetically reactive, it may be affecting the sensor operation. Cleaning the dust out may fix the problem, at least until more of it forms from wear.

In this event, if the wear only occurs up to a point where the metal being worn off no longer rubs against whatever is wearing it, and still functions correctly, then it wont' fail again after this (at least, not for this reason).

 

[Renzo]

I contacted kclamber electronic company directly, since not the seller buybestgear or lankeleisi-eu showed very little interest on my case, bbg just wanting more money out of me and lankeleisi-eu actually ghosting me after few messages with a final note of "a person will contact you".

Kclamber on the other hand completely exceeded my expectations and truly came through. I am not going copy/paste the whole email they sent me, but here is a part of it regarding TORG2B:



They also offered me the upgraded part free of charge (free shipping up to $30 so I ended up having to pay for the shipping) so I am very satisfied with their customer support and integrity/backbone, something buybestgear and lankeleisi-eu both seem to lack. The upgraded product they are sending me is the TORG2H .

 

[Renzo]

I received the torg2h today. Some notes as the installation is different from the usual "open drive side first":

• the drive side BB cup (spider/chaingring) must be screwed in first as it has the teeth that hold the torque sensor body in place and one does not want to rotate it when the sensor is installed
• next the sensor cable needs to go through the hole that is in the bottom bracket and then one can push the torque sensor body in carefully to avoid damaging the sensor cable
• after all that is done just screw in the left side BB cup, but do note that this is "shorter" than the torg2b for example and therefore it could cause some clearance issues for your tools, depending on the bottom bracket box geometry

Now one just needs to plug in/attach the sensor cable to the controller along with any other cable that was unplugged (if there were any).

My initial ride from today reveals few things from the torg2h sensor:

• the start is seamless, no small "nudge" when the assist starts
• the sensor is very smooth when active
• assist is very linear to the proportion of your pedalling force
• the motor noise is reduced (compared to torg2b)
• I could easily crawl ~5km/h with any given gear at maximum PAS assist level (torg2b was able to do 8km/h or so)
• the overall feeling I got is that it feels "easier" to pedal with my bike. Probably better torque signal quality/PWM signal modulation or something else?

As for the final note, I don't think the sensor can break in the same way as my two torg2b's did as the installation is different and there is no force applied from the BB cups to hold the sensor in place with 0,8mm clearance. Here's a view of the sensor being installed from the specsheet/manual:



Let's hope this is a lasting solution for me.