Power meters tend to be a delicate balance in economy vs. accuracy and reliability, with a consistent negative correlation between the two categories. Quarq’s power meters are typically the exception to this rule, and the BB30 DZero Carbon Power Meter Crank Arms represent the culmination of a decade of the brand’s industry-defining R&D. Chief among these developments is the power meter itself, which saw a healthy amount of retooling for the DZero model. Overall, Quarq claims that “150 documented improvements” inform the evolution from the previous models to DZero, but the most important is to the heart of the meter itself: the strain gauges and measurement circuitry. It still incorporates five strain gauges strategically placed throughout the spider in order to measure the Newton meters you’re throwing into the pedals. It’s also still got the same claimed accuracy of +/- 1. 5%, so its numbers are 0. 5% more accurate than most meters, but the new design requires less correction in order to maintain accuracy in drastic temperature changes. Fewer corrections mean the DZero also better rations battery life than Quarq’s previous power meter models, though when the battery does go out, you can still change it without tools or having to ship the whole thing to the manufacturer. The DZero system’s accuracy is further boosted by the return of Quarq’s 10k dynamic temperature compensation technology, which alleviates the need for constant, mid-race zeroings in variable conditions. Even if it’s just coasting for a few seconds or toggling through your head unit to the proper option, it can still be the difference between winning and losing. It’s also obnoxious as hell. The DZero is equipped with an auto-adjust schedule based on a constellation of around 10,000 data points that chart how the unit responds to temperatures ranging from zero to 130 degrees Fahrenheit. This lets the power meter figure out the atmospheric details for you with minimal drift, so you can focus o…