Crank-based power meter manufacturer Quarq, a division of SRAM, is expanding its range to include Shimano road and XX1 mountain crank options in 2015.
Quarq’s Shimano-compatible Elsa RS
The new Shimano-compatible Elsa RS is built around a pair of hollow carbon fiber crank arms of Quarq’s design. It uses a spider for Shimano’s proprietary 4-arm chainring standard, allowing users to mount Dura-Ace 9000-series chainrings to improve shift quality (and the aesthetic) when paired with a Shimano drivetrain.
As with all of Quarq’s latest power meters, the Elsa RS spider houses a user-replaceable CR2032 battery, worth about 300 hours of ride time, an LED indicator light, and a printed ANT+ code for easy connection to any ANT+ cycling computer. The RS electronics also include active temperature compensation, improving accuracy and consistency as temperatures fluctuate. Thanks to this new feature, Quarq says the Elsa RS is its “most exact power meter to date.”
The use of Shimano’s 110BCD standard and proprietary chainrings allows riders to chose between compact (50/34-tooth), semi-compact (52/36-tooth) and standard (53/39-tooth) chainrings, all with the same crank and spider. Quarq’s OmniCal feature makes swapping chainrings easy as well, as it automatically compensates for the changes in torque brought on by different ring sizes.
The Elsa RS will be available in 170mm, 172.5mm, and 175mm lengths, has a Q-factor of 145mm, and weighs a claimed 616 grams (GXP, 110BCD, 172.5mm). Bottom bracket options include GXP, PressFit GXP, BB30, PressFit 30, and BBright.
Retail price is set at $1,600 for the GXP version and $1,650 for the BB30 version.
Quarq brings power to XX1
The new XX1 power meter is built specifically for SRAM’s single-ring mountain bike drivetrains, XX1, X01, and X1. All of the electronics are the same as Quarq’s road units — ANT+, LED indicator light, active temperature compensation — except squeezed into a smaller 104 BCD spider.
The rather old school 104 BCD (bolt circle diameter) spider means that the smallest compatible SRAM narrow-wide chainring has 32 teeth — four more teeth than the smallest available ring for SRAM’s normal single-ring cranksets, which are 76 BCD. That limits the Quarq XX1 to faster riders and/or faster bikes.
Thankfully, aftermarket chainrings from RaceFace, Pacenti, and Wolf Tooth are available down to 30 teeth. The Quarq XX1 is sold without chainrings.
Carbon fiber arms, available in 170mm and 175mm lengths, and a low-profile spider help keep weight relatively low, 626 grams for the GXP version without a ring.
156 and 168mm Q-factors are available, as are GXP, PressFit GXP, BB30, PresFit 30, and BBright bottom bracket options.
Retail price is set at $1,500 for GXP and $1,550 for BB30. SRAM X-SYNC narrow-wide chainrings range from $105 to $127.
Both the Elsa RS and XX1 meters will include a new, integrated, accelerometer-based cadence function, removing the need to attach a magnet to the frame. Every Quarq power meter shipped from the factory after August 14 will include this new feature, and all Quarq meters with a visible LED and ANT+ code can be have the feature added simply by updating firmware.
Performance of the accelerometer-based cadence is “excellent up to 160rpm and in all but the most extreme vibration environments,” but those seeking utmost accuracy can still attach a magnet for measuring cadence.