Trek Duotrap
 

My ‘23 Emonda has this on the inside of the non drive line side of the chainstay.

I believe a spot to install a Bontrager sensor, seems to be combination of speed and cadence. Is this actually a speed sensor ?, I would think a sensor of any kind would need to sense wheel revolutions. Cadence I could see if it had a corresponding shoe sensor, How exactly does this work, the Trek info is somewhat vague.

https://cimg8.ibsrv.net/gimg/bikefor...b48200b92.jpeg

Yup. Speed and cadence. I have one on my Domane. Feeds data to my Garmin. Need a magnet on the left crank for cadence and one on the spoke for speed/distance. The magnet holder on the crank did not work for me. I used double stick tape. Looked better.

https://cimg7.ibsrv.net/gimg/bikefor...3ac211db9.jpeg
The magnet I got off amazon as I needed a thicker one. You can see it on the crank. The spoke magnet I think came with the Duotrap or I may have used another one. I cannot remember.

The sensor does stick out. Also when I put the road carbon wheels on my Checkpoint I put an axle speed sensor on the front hub. The Checkpoint does not have Duotrap.

The Duotrap has a 2032 coin battery. One has to remove a screw to remove the sensor and change the battery. The only real advantage I see is a cleaner look on the crank and front hub without the other type of sensor straps showing.

It is just a plug taking up the space the DuoTrap speed/cadence sensor. Depending on a lot of other things, some of which include what GPS/cyclometer device you have, what your future plans are for other things you want to get such as a power meter, you might not want the Bontrager DuoTrap.

A crank or pedal based PM will also give cadence. If a PM is in your future desires. And you might find for distance, your GPS is more than accurate enough for your needs and not need a speed sensor. Or prefer to get just a wheel sensor which can be less than half of that price for the DuoTrap.

OK, about what I expected. I have zero need for cadence so will skip on spending $75. Speed sensors I do use, but are only $40,

it's unfortunate that the ecosystem for the Duo is limited to what it is. That little void is at times on the mind to find a new purpose for it, but that likely will never happen either. No one offers a light to be flush mounted in that cavity, otherwise I'd have put one in by now.

I’d like a flush fitting cadence only sensor. Then leave the speed/distance sensor to the hub. Since the calibration is to the wheel/ tire combination. Mmm. Have to take a closer look at the Duo.