Quarq

SRAM XX1 Power Meter Crank Arms - GXP

The Quarq XX1 GXP Power Meter Crank Arms hook your GXP bottom bracket mountain bike up with the same technology of the power meter designed for SRAM's premier road crank, Red. As Quarq is now an ancillary to SRAM, these are the carbon XX1 crank arms, simply combined with a CNC-machined aluminum spider that houses the power meter itself. The result is the holy grail of Power meters — a high-performance crankset that feels, looks, and acts like the SRAM's beloved one-by drivetrain. It doesn't sacrifice the weight savings associated with a one-by; the arms, spider, power meter hardware, and spindle weigh in at a mere 626 grams.

The XX1 Power Meter measures watts with five strain gauges strategically placed throughout the spider in order to measure the Newtons you're throwing into the pedals. Its claimed accuracy of +/- 1.5% means it does so with 0.5% more accuracy than most meters, and since it communicates to your head unit via ANT+ wireless, your current computer is likely already compatible with it.

The proprietary Power Balance technology is yet another reason to ride Quarq. Power Balance measures and displays the power you're generating in both crank arms separately, so you can compare the two and identify weaknesses in both legs to target for improvement. Our favorite feature is the ability to change the system battery yourself. Other systems require you to mail in your crankset for battery swap-outs, but the Quarq SRAM XX1 Power Meter features a tool-free user replacement system as well as a predicted 300+ hours of ride time per battery. This means more time in the saddle and no need for backup cranksets.

One issue that has plagued power meters since their inception is wildly variable temperatures at events like Tahoe, where rapidly rising or falling mercury necessitates one or more mid-event zeroings. 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 a pain. The XX1 Power Meter now addresses this with a dynamic temperature compensation that includes over 10,000 data points. The gist of this is that it figures out the atmospheric details for you with minimal drift, so you can focus on turning the cranks, not babying them.

The Quarq XX1 GXP Powermeter is waterproof for 30 minutes while submerged under one meter of water, just in case you want to take your bike on the swim leg, too. It also measures cadence with an AxCad accelerometer, and it's compatible with various training software such as Training Peaks WKO+, Training Peaks, Golden Cheetah, and Strava.