Gear inch/ratio question

SkullheadWilderness Umm why is a maths thing. there's an excellent skid-spot calculator somewhere in the web, it'll let you work out how many spots different rations will give you. Seems odd numbers/prime numbers (uuuh I think) seem to give more skid spots, which is maybe why I never seem to be able to find a 17t sprocket when I'm buying.

This is a sweet little skid patch calculator widget for Mac 'eds.
I use it to aid day-dreaming of skid pirouettes at work.

http://www.apple.com/downloads/dashboard/calculate_convert/skidpatchcalculator.html