To give you a sense of how Quarq is already on top of technology and moving forward, take a look at this CinQo Saturn SRAM S975 Wireless Powermeter. The S975 arms are new to SRAM's non-series cranks, made of hollow carbon, and 60g lighter than last year's S900 crankarms. Quarq isn't waiting for the market to move before they employ an upgrade; they're moving along, trying to keep up with or ahead of changes.
Quarq is one of SRAM's power partners. The CinQo Saturn spider is the brainchild of James Meyer, an engineer and aspiring triathlete with time on his hands and no money, so he tried to figure out how the SRM did its magic in order to build and ride his own powermeter for a fraction of the cost. The Saturn is the fruit of that labor, so named for the ring that sits in front of the small chainring. CinQo for the five-arm spider. Several years of development and countless miles of testing behind it, this is no beta-version, but a full-fledged, proven meter.
Thanks to Area Network Technology (ANT), this is a wireless power meter that works with every power-compatible ANT+ Sport equipped central processing unit (aka bike computer) on the market. And, as a result, we're selling this without a head unit so you can pick your dashboard of choice. ANT+, if you haven't been following wireless technology, is the hottest thing in bike computers and is rapidly consigning wires to the dustbin of history. In order for this pairing to occur, there needs to be an ANT+ transmitter hidden in the crank spider, which there is.
The CinQo unit has ten strain gauges, each with two grids, embedded in the spider. That's 20 measurements of the flex/displacement resulting from pedaling torque. The accuracy is +/- 2%, which is pretty much the margin of error for all power meters these days. The crank spider, just like the SRM, is turned on by a magnet placed on the frame near the inside of the spider that trips a reed switch which then turns on the unit. The CinQo is powered by a CR2450 watch battery mounted on the outside of the crank inside a waterproof screw-top case based on the design of a contact lens case.
The cranks are calibrated in Spearfish, South Dakota, where the Quarqs are made. Since calibration can't currently be made in the field, you should stick with chainrings of similar design. The big thing to know is that solid time trial chainrings, like those from FSA and SRAM, should not be swapped in when the unit has come with regular road chainrings as the change in flex will change the calibration and reduce accuracy; if you do want to mount time trial rings, you can send the unit back to Quarq, and they'll recalibrate it for you. For this unit, you'll get most accurate readings with FSA Pro and Super Road rings, Rotor Q-Rings, Shimano Dura-Ace and Ultegra rings, and SRAM Force and Red rings. If you have Campagnolo 11-Speed on your bike, they recommend Stronglight's 130mm BCD Campagnolo-compatible rings. If you're a Campagnolo 11 user and want a compact crank to go with your Quarq, they recommend using Campagnolo-compatible 10-speed rings (not Stronglight 110mm BCD rings). They do not recommend FSA Campagnolo-11 compatible chainrings in either configuration. If you go with Rotor compact chainrings, you need to go with the Rotor OCP #3 outer ring, as this is the only compact Rotor ring that doesn't interfere with the battery mount.
The CinQo Saturn spider is compatible with the following bike computers: Bontrager Node 1 and 2, CycleOps Joule, Garmin Edge 500, 705, and 310XT, iBike Sports Aero, and Specialized Speedzone Pro.
The unit runs off a single CR2450 battery, which is a watch cell available at your local electronics store, pharmacy, and/or supermarket. Estimated lifetime is 400 hours of riding. For people riding daily, switching it every six months should be an easy way to prevent having the battery die on a ride, though those pairing the Quarq with a Garmin head unit will have the benefit of a low battery icon, thanks to a signal the crank sends out that only the Garmin's can currently read. For those living in climates with a cold winter, battery life may be a bit shorter during the frigid months. As Quarq is based in South Dakota, they've ridden with their cranks and still had power readings transmitted at zero Fahrenheit, though your experience may vary (a fresh battery will be able to resist the cold better).
The Quarq CinQo Saturn SRAM S975 Wireless Powermeter comes in either a standard (130mm bcd), or compact (110mm bcd) configuration. Both the standard and compact versions come with SRAM Red chainrings. It's available with three crank arm lengths -- 170mm, 172.5mm, and 175mm. The powermeter comes with the cranks, a battery, a magnet mounted on a ring to be placed between the drive side bottom bracket cup and the bottom bracket shell, two loose magnets that can be applied with adhesive putty (also included) to bikes where the bottom bracket ring doesn't fit, and instruction manuals specific to the SRM crank and Quarq unit. It does not come with a bottom bracket; this must be purchased separately. It does not come with a head unit or wireless speed sensor; these also must be purchased separately.
Please note: In terms of bottom bracket compatibility, you need to use SRAM's GXP or Black Box GXP external bottom bracket. If you've got a BB30 bottom bracket, you can get an adapter pressed in. If you want to mount the crank on a BB86 or BB90, it will work with a SRAM bearing kit specific to those bottom brackets.