i have some on my fixie. i think they are usually marketed as bmx cranks. i run the 170s

you generate more power (by having more leverage) with longer crank arms if you bb is lower to the ground you would want shorter cranks to avoid pedal strike and toe over lap. luckily having a tr-frame i have a high bb and no toe over lap.

i run a 40tooth rocket ring in mine, but you have to be carful to find the right crank arm bolts to go into them

plus i ran them on a pedal cab with no issue for several months.