This counter is excellent (wireless). A small sensor installed on the front fork (with a small elastic supplied) to install a small magnet on a spoke of the wheel to the height of the sensor and then the base to install (with elastic too) on the handlebars . On this base, you will put the counter that starts and is easily removed by 1/4 turn (literally!). Installation with elastic can be made also with small plastic colsons (undelivered but the mounting is also described).
As the clock setting, the more difficult is to determine the length (in cm) of a wheel revolution. But thanks to the instruction manual supplied, you will quickly determine using the comparison table (size of your rims, 26 inches ...). For the rest, I refer to the description of the article on the site.
