The iBike Pro.
The iBike Pro power meter is a relative newcomer to the arena of power-measured training. Produced by Velocomp of Dallas, Texas (www.iBikesports.com), the iBike bills itself as an affordable alternative to the higher priced Power Tap, SRM and Ergomo power meters.
The first question I had about the iBike was: How does it measure power without a sensor at the bottom bracket or rear hub? Simply put, the iBike uses the principles of Newton's Third Law of Physics, which states that applied force and opposing forces are equal. By measuring the various opposing forces that a cyclist must overcome (i.e. gravity, wind, inertia, rolling resistance), the iBike can calculate how much force you're producing (watts) to overcome those opposing forces (in keeping with the laws of physics: Power=Force x Speed). This is the wattage the cyclist is producing.
Set up and installation of the iBike was quite simple. It took only about 30 minutes to go from box to bike. After entering basic data--including combined weight of rider and bike and wheel circumference--I was ready to ride.
I used the iBike for three months on my training rides and found it to be mechanically reliable and consistent, which was what I was most concerned with. Without consistent data, a power meter is useless. However, I did not compare the accuracy to other power meters.
The companion software--a historical tracking and graphing program--is easy to use and perfect for tracking your progress over time. The iBike is also compatible with Cycling Peaks and Training Peaks software, which allows for more complex analysis, such as the ability to upload your rides for a coach to analyze.
There were many things I really liked about the iBike: Cost (less than $500 retail for most models), reliability (I had a bad wheel sensor initially, yet after receiving a replacement I have had no problems at all with the equipment), consistency and the ease of portability between bikes.
Having said that, there were also some negatives: It won't work inside (since it needs outside opposing forces to work), though, to be fair, iBike states this on their website. This wasn't a deal breaker for me, but for someone in a colder climate who trains inside a lot, it is something to consider. Also, the battery had a short life--only about eight hours--but it's a relatively inexpensive watch-type battery, so this isn't a big deal.
The biggest challenge is mounting the iBike on a time trial or triathlon bike. In order to mount the iBike, you need a handle bar extension that drops down between the aero bars so the sensor can get clean air to process. If you use an aero drink system with a bottle between the aero bars, this is not possible.
The other issue was mounting the iBike between S-bend or R-bend aero bars. Turbulence is created by the hand position on these types of bars, which in turn disrupts the air flow to the iBike, causing inaccurate readings. If you use the older-style bars with ends that turn up, you may get decent readings since the hands are higher up and don't create a slipstream under the bars.
Overall, the iBike is great for those budget-conscious folks who want to improve their cycling and don't require overly complex or detailed analysis of power data. It's a solid alternative to the high-priced, tech-savvy power meters that currently crowd the market. Simplicity can be an excellent selling point.