Quarq SRAM Red DZero Power Meter Crank Arms - GXP

Industry literature discussing powermeters is replete with hyperbolic claims, but Quarq's SRAM Red DZero Power Meter Crank Arms for GXP bottom brackets enjoy a pedigree that speaks for itself. The Red DZero is the latest member of a family that includes wins in the most prestigious races in the world, ranging from Roubaix to Paris and Kona. It incorporates every advancement that Quarq has made in power meter technology over the last decade, and it combines those advancements with an improved measurement circuit for even more accurate data across variable external conditions.

As with the rest of the DZero line, the Red model still incorporates five strain gauges strategically placed throughout the spider in order to measure the Newton meters you're throwing into the pedals, and—except for the alloy spider—it features the same Exogram carbon crank arms and graphical treatment as the standard Red crank. 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 latest SRAM Red power meter model also better rations battery life than the previous generations, 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 Red 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 on turning the crank, not babysitting it.

The DZero with SRAM Red branding also hosts Quarq's Power Balance and Omnical features, which record total output and output for either leg individually (Power Balance) and let you swap chainrings without recalibrating or negatively impacting accuracy (Omnical). As with previous Quarq models, the DZero communicates to your head unit via ANT+ wireless, but Quarq also adds Bluetooth to this generation. Up till now, we've always tempered the obligatory head unit-compatibility statement by writing that your current computer is likely already compatible with the power meter; now, we can just state outright that it is compatible.

We recognize that there is value in cycling components that can stand up to the elements we often encounter throughout the course of a year of training, but Quarq demonstrates its penchant for being overly thorough by ensuring that the unit's internals can handle comically extreme conditions. The system is waterproof for 30 minutes while submerged under one meter of water, a feature that will come in handy on days you take your bike on the swim leg, too.

Since the DZero is effectively a catch-all for almost every bit of tech Quarq has thrown at the power meter problem over the past decade, it includes the AxCad accelerometer, which provides cadence information without any additional sensors or magnets. The DZero is also compatible with training software suites including Training Peaks WKO+, Training Peaks, Golden Cheetah, and Strava. Unlike previous versions, the DZero's Bluetooth compatibility lets it sync with the Qalvin BLE app to easily tune, tweak, and set zero offsets.