Feel over gear you can't hear it well some times .it's up to you to find what you like or thinks better I had 36t and think a 30t wood be best .my pocket bike motor on push bike with 20inc wheels was a guess to at lest get it to go like a pocket bike . Evon better 54t lazer cut sproket .then it reved out with no pedaling so 52t next still revs out still no pedaling .mybe 2t off more and that's it 70kmh plus .and no pedaling .any more and I would need to pedel . And probably hit 80kmh /50 mph ..I don't won't to pedal ever lol