tip--get them used, people sell them a lot (give up on them)
tip 2--start in a doorway so as your elbows can be stuck out into the doorframe to catch you if you loose balance (this makes a happy first try)
tip 3--USE Clipless shoes (ie spd, look...blah) this is a must--clip into one font pre mount-squeeze breaks and lean on your handy doorframe-then get other foot (this is only till ya get the feel)
tip 4--peddle and i think a little more resistance is easier then spinning free and fast (use your gears-start low and build up--try different ones) also try different grips--i think the more into you bars the more stable
tip 5--hold your line-lol. look at top of front tire--lot feet. steer or lean to keep straight
tip 6--use breaks and doorframe to get off
tip 7--if you hate your rollers-i need a pair (i like the small diameter ones that fold in pvc over aluminium--cheapest that ride smooth--sell me them cheap!!! lol)
hope this helps...i think you do not need to spend a ton. pvc weighs less and sell less (easier to lug around and buy) some fold 2 or 3 times--2 is cheaper-i like that. size of the drums differ--i like skinny ones, however some will diagree. i thinkthey are easier--others think i am wrong that the bigger ones smoother and vibrate less.
i say try them first and see if you like it--cyclops seems higher end trax lower--nasbar used to make them, not sure if they do anymore-performance might. look at ebay.
