I have a Zero bike but I think it's good for any bike with a drive belt. I started using the Gates app on my phone, which used a microphone to listen to the strap as you pluck it like a guitar string. Totally inconsistent - I don't think I had the same frequency on 10 measurements, but maybe 8 out of 10 measurements were "in field". It turned out to be VERY tight and ripped when I was 40 miles from home. So I ordered this baby after being taken to a car dealership to order and install a new belt. That way I can check the voltage regularly and don't have to fiddle with the Gates app. money well spent. As the title suggests, it took a few tries to figure out how to get consistently accurate (and reproducible) readings. You want the center of the tester to be exactly in the middle of the two rollers and press the pad of your finger until you hear a click and carefully remove the tester without disturbing the reading stick. This is easier than described; it just needs a few trial runs. Have fun driving!