Cyclists apply forces to bike pedals to overcome the forces resisting forward motion (hill climbs, wind resistance, rolling resistance, acceleration, etc.) Traditional power meters like SRM, Powertap, and Ergomo measure the forces applied by the cyclist (direct measuring).
The new Ibike Pro is the first power meter that measures the resistive forces working against the cyclist (indirect measuring).
iBike Pro is the first power meter measuring resistive forces
The principle of iBike Pro is that forces applied by the cyclist are precisely the same as the forces from wind resistance, rolling resistance, and gravity. Thus, if you know these factors, you can calculate the forces applied by the cyclist. The iBike Pro measures wind speed, hill gradient, and bike speed.
Body position does not affect power output
As you can guess, several variables can possibly affect the measuring. One of the biggest problems, in my opinion is that the power output will not change if you change body position. That means that data from the rides will reflect the average power output rather than the actual power output.
iBike Pro website FAQ about the body position problem:
“Most riders stay in the same position about 90% of the time or more, so the percentage of the total ride where there is a wattage difference won’t be great. In addition, the iBike Pro assumes that the athlete remains in the same riding position, so changes in riding position will not be reflected by changes in the iBike’s wattage readings.”
My opinion about iBike Pro (I haven’t tried it yet…)
It is an exciting concept, but it is challenging for me to understand why they measure power indirectly. That doesn’t make sense to me. I am not sure that this product can be used for serious wattage training, but I would like to try one to see how it performs. Some good things could make iBike Pro a competitor for the other power meters: It weighs only 60g and costs 399$, which is nothing compared to the more expensive and heavier products on the market.