Spider-Based Power Meter

Power Meters are gadgets on a bicycle that measure the power out put of the person riding. Most power meters in the market use strain gauges to measure torque applied thus when combined with angular velocity it calculates power.
These power meters usually come with a handlebar which is a mounted computer that displays information about the power generated by the person riding. Currently in the market, there are three power meter types within the crank spider location. They include: Quarq, POWER2MAX, and SRM.

Quarq is a crank based power meter that measures the torque applied through both pedals and through a strain gauge that is positioned at the crank spider. The instrument that measures is called the crank which is mounted to the crank and chain rings. It requires specific crank sets but it can be relatively simple to interchange between bikes depending on compatibility. The accuracy is at par with other units in the market and also you can swap chain rings without an issue. It also quite affordable compared to other power meters.

POWER2MAX is a crank based power meter. It has a growing crank set compatibility matrix that gives it good accuracy. It is the least expensive crank based power in the market. It uses fewer strain gauges. However, purchasing and servicing can be difficult and also, it does not have a method of turning off off auto-zero.

SRM is also a crank based power meter. It is a well established brand with a well understood product.It has excellent data capture and data accuracy especially on the head units. It is not just limited to the SRM head units, you can use any other head unit you like. It is quite expensive and servicing it is not as easy as other power meters in the market.