Training with power has long been the norm for pro roadies, and has made massive inroads with the weekend racer as well. While pro MTB riders have embraced the concept, it has yet to truly make the jump to the amateur ranks. That is quickly changing. Spending thousands on a new piece of equipment is always a nerve-racking proposition, and getting started with power is certainly a four-figure purchase. Determining which is a quality product, and which one is right for you, can feel like post-doctorate research. There is a shortcut. SRAM has been on the acquisition warpath and snapped up some of the best and brightest new companies. Follow their lead and you can’t go far wrong.
The most recent company to take refuge under the SRAM umbrella is Quarq, the power meter company. With SRAM’s focus on mountain, Quarq has just announced the 2x10 Quatro MTB crank-based power meter. So, why did SRAM snap up Quarq? The increasing popularity of riding with power and the integration of electronics and drivetrains make power metering capabilities an appealing proposition for a company like SRAM. But why Quarq specifically?
SRAM’s buying power means just about any system currently on the market was a possibility. Quarq made perfect sense because it was not married to any particular head unit. They transmit information wirelessly, using Garmin’s ANT+, which appears to be the winner in the power transmitting standards war. In addition to Garmin units, CycleOps, Bontrager, and Specialized make ANT+-compatible head units, but get an ANT+ key for your smartphone and the exploding app market has you covered at a fraction of the cost. SRAM also had a history with Quarq, mating their cranks to the Quarq CinQo road meter.
The history of Quarq is short, beginning in 2006 when founder Jim Meyer wanted a power meter. Instead of pillaging the savings account, he built his own; you can do that when you have a degree from MIT. Quarq was born and rapidly gained respect. In a few short years it was being ridden by pro roadies, Ironman champions and Olympic medalists alike. The Quarq power unit itself is renowned for its accuracy, +/- 2%, which is essentially the industry benchmark.
With SRAM on board, that power meter now resides within a tough MTB-specific crank. Carbon crank arms turn a CNC-machined aluminum spider and, a must for the MTB, the system is totally waterproof so don’t sweat that next river crossing. While the crank’s X-Glide shifting is clearly tuned for SRAM drivetrains, the bottom bracket options are almost universal: BB30, GXP, GXP Press Fit, and Press Fit 30. Battery life is reported to be well beyond 300 hours and replacement of that battery is an affair that takes about 30 seconds and requires no tools.
The Quatro MTB Power Meter crankset weighs 814 grams with bottom bracket. That’s only 60 grams more than SRAM’s top-of-the-line Truvativ XX crank and 67 grams less than the X9 crank. Weight penalty? Hardly.
The cranks come with 39-26 chain rings, and Quarq’s measurement system requires the unit be calibrated to those chain rings at the factory. If you want to run a different ratio you may lose some accuracy, although to be fair, not enough to truly affect the units ability to be a valuable training tool. If you do change the rings, the torque requirements on the chain rings are high, and it’s important you use the steel bolts included, as aluminum won’t reach the required 10 nm without making a god-awful racket and most likely stripping.
The cranks cost $1,795 for the GXP version and $1,845 for the BB30; a comparable SRM will cost in the neighborhood of $3,000. For the math impaired, that is quite a bit more. With a top-of-the-line Truvativ XX crank running over $500 anyway, the power metering itself costs you around $1,300.
The exciting thing about this new marriage of SRAM and MTB power—the wattage kind, not the buying kind; SRAM has had that power for years—is the potential it has to make us faster. Roadies have been using power for years to ensure they are dosing their effort to perfection. They essentially say, “I can hold X amount of watts for Y amount of time,” and they then perch themselves on the nose of their saddle, hunker down, and hit those watts exactly.
Using wattage for the mountain bike rider is very, very different. The courses and races we ride rarely allow us to dose our effort evenly. There is just too much mountain in our biking. We need to be able to produce high levels for a short period of time, and then recover as we hit the brakes for a technical section, or scrub speed for some switchbacks before jumping on the power again to keep the speed up over another steep pitch or rocky climb.
While a power file on the road has a rolling appearance, a mountain bike ride of the same duration and output, unless it’s all fire road, will look like a printout from a Richter scale, all peaks and valleys, almost as if the power was either on or off. Utilizing wattage while training allows even the most non-demanding trails stand in for a technical race circuit. In only a few rides over a technical circuit with a Quarq, you’ll know what numbers you need to hit during those big efforts and can hit them on any trail. Ride tempo for a few minutes, then jump to peak wattage for a count of 20 or 30, then back down to that tempo. How many technical bursts does your chosen circuit require—40, 50, 60 or more? That should give you an idea of how many times you need to be able to dip into that well over a race distance.
Training with power isn’t just for roadies anymore. The power files will look as unique as the trails on which we race, up and down, full of switchbacks and steep pitches, but there is no question the passionate racer will be able to use their power numbers to get faster. Thanks to Quarq’s meters and SRAM’s dedication to mountain biking, the options for all of us without sponsors just got a lot more appealing.
Details: 2x10, 39x26, 170 mm/175 mm crank length, Wireless TECH: ANT+
Weight: 814 grams (GXP BB)
Price: $1,795 (GXP); $1,845 (BB30)