Cycling on the traditional two-wheeler has begun to change for cyclists. While the overall design of the bicycle is simple, and excluding obvious evolutions as the motorbike and the motorcycle, it has remained relatively unchanged in design and operation. With Greg LeMond’s introduction of the strain gauge, however, a new field of cycling had emerged. Power meters that could tell you how much energy output in wattage you were getting per journey, and from there, how much your heart was getting as well. For every innovation there is a purpose, and the reason behind the strain gauge was conceived through the medium of professional cycling. Thus the birth of the strain gauge power meter.
Being the original model of change, the strain gauge is best understood through its technical specifications. In essence, the strain gauge is a an electrical conductor applied to various points of tension on the bicycle that is likely to receive wear over time. The gauge, sensitive to the slightest deformities, when modified, creates a measure of tension through an increase or decrease of electrical resistance, measured in ohms. Relatively accurate under strictly ideal conditions, there are a number of offsets that can minimize its accuracy. Temperature is a factor that can cause a deviance to the measured resistance, as well as calibration and installation. However, with the development of this product over time, various encapsulations have resolved some of these sensitive areas. Installation varies from the wheel hub of the bicycle, the lower bracket, pedals, and the spider crank shaft. These areas are where the force is most immediately applied, thus the change in torque easiest to gauge.
With the many variations in power meters on the market, put simply all the different types are essentially employing strain gauge technology, with the exception of the handlebar units that use gravitation and gyroscopic measurements.