Originally Posted by godspiral
I noticed they are all pretty expensive. If you know your speed, and your gears, you can calculate your precise cadence.
here you go
this is the one i bought and the ebay store i bought from. had the comp in my hands in 4 days
http://cgi.ebay.com/TOPEAK-COMP-140-...QQcmdZViewItem
Its a nice little unit unclips from the mount max cadence current avarage same for speed. I think it has a max cadence of 200 before it flips and represents the cadence via flasshign numbers.
Seems to be quite reliable as well. I got mine about a month after i started riding last year (put 800ish miles on it last year and little over 400 this year.)
Give it a try its a great little comp for the money.
It is a wired unit obviously.