I just put a sigma bike speedo on and it is awesome! The only thing i would recommend (only thought of the reasoning on my first trip!) that you go for the model that allows two wheel sizes...i thinkit is their most expensive sigma model...and it is still only about $40 cdn. The reasoning is that if you travel between U.S. and Canada, having the two measurments (metric and imperial) allows you to choose between km and mph with the push of a button. With the single wheel size models, you have to have the measurement written down somewhere and manually enter it to swith the computer over. Otherwise an awesome addition (including time travelled, odo. and fun ting...max speed travelled on journey. Measures almost exactly 10% off, with an indicated 220 km per on bike registering 200.7 on comp...and that was all she had. I just got in tonight from a great ride testing out my customized headphones but will start a thread for anyone interested and maybe get pictures up as well.