i use my noggin', that's it. when i raced alot, i'd use a heart monitor now & then just to sanity check what the upper thresholds were. but as the poster above said, when you gotta go, you gotta go, regardless. some folks love digging thru the data and analyzing it, which is cool. whatever floats yer boat. neat thing to observe is the amazing amount of tech available to any recreational cyclist. it really is mind-boggling. and that tech can be utilized to great benefit if properly used, no matter what your baseline. when combined with at least half decent talent, of course. can't turn a donkey into a thoroughbred, but can at least get it to the point of a good trot!
