Wednesday, August 14, 2013

Gear Review: Quarq Elsa Crankset by Kirk Groves (@LSVLKirk)

I bought my first power meter in 2008, a PowerTap. Admittedly the first two years I wasn’t 'really' using the power in my training. The power files were little more than interesting data to me. Flash-forward several years and power is now integral to my training. Even when I’m not following a structured workout I use power for pacing. Additionally I use TrainingPeaks and their Performance Management Chart to track fitness. In early 2013 I grew tired of not having a wheel choice so I decided to purchase a crank based power meter. I also found the axle on the PowerTap wheel flexy. I'd experience brake pad rub every time I’d hammer out of the saddle.

I considered both the both the 2012 Red Quarq and the Elsa 10R. An SRM was clearly out of my budget. The primary differences between the Red and the Elsa are compatibility, chainring choice and weight. With the 2012 Red Quarq you have to run a full Red 2012 drivetrain. I wish I had Red 2012 on all my bikes but that's not likely unless I win the lottery. On my road bike I'm running SRAM Red Black, one CX bike has SRAM Force, my new CX bike will have Shimano and my TT bike has SRAM Apex. I wanted the ability to run the Quarq on all those bikes. Further I run smaller chainrings for CX. I haven’t seen Red 2012 compatible chainrings (only 4 bolts) in CX specific sizes. A further nice benefit of the Elsa to weight-weenies is slightly fewer grams than the 2012 Red version. So with my decision made I placed and order through JD and Foxtrot Wheel and Edge, an authorized Quarq dealer, and the crank arrived in 2 days.

Quarq Driveside
Features
* +/- 1.5% accuracy
* Exogram™ Hollow Carbon crank arms
* Power Balance™
* Omnical™
* LED indicator
* CR2032 battery – 300 hours of riding time
* ANT+™

Quarq nondrive
Swapping batteries is a breeze, no tool required. There's an LCD light that shows the crank is sensing the magnet and 'awake.' The crank speaks ANT+ so I can use my Garmin Edge 500.

I ordered the compact crank with 50/34 chainrings. I can't climb like Fangman or Jackson and I need a smaller chainring than a 39 for some of the steeper climbs in Colorado. At the same time I descent pretty well given my weight. A new feature with this generation of Quarq cranks is the ability to switch chainrings without having to ship back to Quarq's for recalibration -- Omnical. I've been working hard this year and am climbing a bit better, hence I no longer need the 34. I've since switched to 52/36 chainrings so I can still bomb down descents and not spin-out as quickly. I'll be swapping chainrings for CX soon as well. At the same time I'm going to add a clear protective film to the surface of the crank arms so I don't scratch up this beauty while I'm fumbling to click-in while I'm bleeding from my eyeballs in a CX race.

All the bikes I want to use this crank on are BB30. Moving the crank bike to bike is relatively easy. A magnet is required on the frame hidden behind the crank. The magnet is required to measure cadence and determine the first and second half of the pedal stroke. I apply a magnet on all my bikes with putty and then leave it even when the Quarq is on another bike. I've been right leg dominant since I had my ACL reconstructed in 1996. By displaying PowerBalance on my Garmin I'm able to emphasis a symetric pedal stroke and work on closing the gap. PowerBalance "uses crankset torque to display the ratio of power generated in the right drive stroke (first half, 0-180°) versus the left drive stroke (second half, 181-360°) for each crank revolution." While not perfect it's more than adequate for my needs.

So, does the Quarq do what it's supposed to do, measure power accurately and consistently? I have my PowerTap to compare against and what I've read on the web. Theoretically the Quarq should report a couple watts higher than the PowerTap as it measuring power prior to the PowerTap. That is, there is a small power loss from the drivetrain to where the PowerTap is located in the hub. The Quarq measures at the crank spider. I haven't been able to notice that difference in normal conditions. I also expect that difference is within the specified margin of error. What I do believe is that the Quarq reports higher peaks for short efforts. For example, a sprint might measure 1500w instead of 1400w on the PowerTap. In my experience, an LT interval using the Quarq hurts the same amount as one done with the PowerTap.


I'm highly satisfied with the Quarq recommend it without reservation if you're in the market for a power meter.

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