Tacho does exactly what it should, it measures the speed, total distance, even the average speed. What I have not figured out is how the trip meter must be set to 0, without having to reset completely the speedometer. The sensor on the spoke is also quite large, I have to be careful that he does not stumble against the counterpart to the fork, but puts a spoke he is too far away. Nevertheless, the assembly and adjustment is a breeze, material is present, tachometer is fixed with cable ties at the wheel.
Addendum: by now about 4-5 weeks of use is the speedometer unfortunately over, because the cable is pulled out of the sensor, or whatever. I did not fall, had the wheel are inside, there was no one else to it, no idea how that happened, unfortunately, so obviously the whole unit in the bucket, because I have not found a way to connect the cable again. Very unfortunate. So next time be better to invest 3 more :-( thus I would say again to give way 2 the 4 star given.
