For any of my rides, be they adult, kiddie, IHC, etc. etc. I use pretty much the same rpm timing motors, since timing motors' rpms can be all over the place, I've tried to stick with those with rpms under 60 (think minute hand of a clock-that speed), and mine are more in the 15-20 rpm range if you can get them. I have some that are way too slow, like 5 rpms or so, so you have to keep your eyes open when the right rpms timing motors are available.