Track or SingleSpeed Cranksets

thanks smallfurry! I was trying to measure my inside leg length by myself and got an approximate 75cm so will need 165mm cranks only, still it doesn't sound like 5 mm would do much difference and i really feel uncomfortable with the 170 ones...should i just try 165? haven't got muuuch money to burn on cranksets at the moment...

I have a similar inside leg (30") and actually ride 170, although my new bike will have 165. Don't really see why either would be a problem, you're not exactly freakish. Some people seem to notice a massive difference, some none, but 165 sounds about right to me. You could always try something cheap second hand before you splash out.

I too have a 30" inside leg (well 30 1/4"). I calculate my ideal crank length to be 162mm.

But like most short people have mostly used the easily availible 170, and get on OK with it. This is what I have on the CX/commuter/hack.
My fixed has 165's which are alot easier for my stumpy legs to spin, without my upper body starting to bounce.
My SS MTB has 175's which gives me more leverage on climbs, and over obstacles.

IMHO the 5mm is very noticable. But depending on the type of cycling you are doing you can vary your crank length to positive effect. Although for pedaling at constant cadense (ie road cycling) the correct length for your leg measurement is probably worth hunting down.
http://www.machinehead-software.co.uk/bike/cranks/cyclist_crank_length_calculator.html