Found this little gromet thing on the end of one of the spokes of my rear wheel.
I heard a metal click during the ride which is I presume when it got there, but I cant tell if this is a part of my bike or some random junk.
Anyone seen this before?
by AccessGood2368
5 Comments
It’s a speed sensor for bike computer.
Magnet for a speed sensor. Goes on the spoke. Align with the sensor and screw or down to clamp the spoke in the groove. Needs to be no more than a couple mm away to work.
As someone said already, it’s a magnet for a speed sensor. The sensor mounts on your fork (or rear stays) and this goes on a spoke on the wheel. As the wheel spins this magnet goes by the sensor and the sensor can tell the RPM of the wheel and give you speed and distance.
They’re secretly tracking you!
In seriousness, back in the day, before GPS sensors were commonplace, we used magnets (along with sensors) to measure each revolution of the wheel, and when combined with the circumference of the wheel, this allowed us to calculate our velocity and distance.
Usually attached to a spoke on the front wheel. As wheel rotates this metal sensor activates the “sender” attached to your fork. The sender transfers signal to the cyclcometer that is attached to your handlebar. Google Cat Eye cyclometer and you’ll understand the set up.