I use a Garmin Forerunner 301 Personal GPS with Heart Rate Monitor on my Actionbent Tidalwave 3. No wires and nothing to calibrate. I use it on a couple other bikes I ride. No messing with wheel diameter changes. I spent more money over the years on other wired/wireless systems than what I spent on this unit. It comes with a program that allows download of the ride data to your computer. Here are a couple of pictures of my set up


The cheapest place I found to buy it was Amazon.com There is a link there also for the bike mount. A 201 mount will fit the 301.

There is also an online service at Motionbased.com that you can upload your rides. They have a free account and a subscription account. Here is an example of one of my uploads to Motionbased. After over a year using my Garmin I can positively say I will never have/need another standard bike computer.