Powertap shimano g3 power meter hubin 2005 we introduced the worlds first ever wireless powermeter and weve been striving to improve upon it ever since enter the g3 the third generation of hub based powermeters the g3s design allows for a simple straightforward way to measure power by mounting the strain gauges in an area where external forces such as spoken tension cannot impact power measurement the powertap g3 is able to deliver 15 accuracy ride after ride more than just a