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  • Quarq DFour91 Power Meter Spider
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QuarqDFour91 Power Meter Spider

Item # QRQ001Q

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Item # QRQ001Q

Crank the power up to 9100.

You've been rolling with your Quarq power meter for some time, enjoying the perks of power, elevated training, and pushing yourself to the max, but you're ready to upgrade your drivetrain and feeling a little panicked at the thought of putting aside your crankset to delve into Shimano's new Dura-Ace 9100 groupset. Fortunately, you don't have to worry too much about a total overhaul in the crank-zone with the Quarq DFour91 Power Meter Spider. This sentient spider pairs with the 8-bolt Quarq crankset you already have decked out on your bike, enabling you to run Dura-Ace 9100 or Ultegra 8000 chainrings on your ride for top-tier shifting and control, with Quarq's newest technology and strain gauges for improved data accuracy.

The DFour 91 encompasses five precisely placed strain gauges throughout its spider to measure exactly how many newton meters you're putting out when you put the hammer down. With in-factory calibration, they are designed to accumulate data within 1.5% of total accuracy —a claim landing 0.5% more accurate than most power meters on the market. Accurate power is well and good, but what makes it even better is the fact that the new design eliminates the requirement of constant calibration and zeroing offsets when the weather changes. Since race days may start early with frosty dew, and end in warm afternoon sun, or send us from warm meadows into drafty canyons, the ability for the internals to self-calibrate reduces the amount of time we need to spend coasting, or messing with our head units, so we can stay focused on the road ahead.

These temperature calibrations are achieved thanks to Quarq's 10K Dynamic temperature compensation technology. It uses 10,000 data points that collect information on how the unit responds to temperatures fluctuating from zero to 130-degrees Fahrenheit, so the unit its self can determine where it needs to be in different weather and create an auto-adjust schedule based on atmospheric details. This lets the power meter figure out where it needs to be for you, so you experience minimal drift and can keep your focus on spinning the crank, not babysitting it.

Because changing temperatures are often paired with changing weather, Quarq demonstrates its penchant for being overly thorough by ensuring that the unit's internals can handle ridiculously extreme conditions, from raging monsoon rains to a winter blizzard apocalypse. The system is completely waterproof for up to 30 minutes when submerged under a full meter of water, giving you the confidence you need to bang out the base miles on the wet and dismal days.

The DFour91, like its sibling, the DFour, uses the same meter as the DZero model, but drops a bolt to fit a Shimano drivetrain— specifically, Shimano Dura-Ace 9100 . Unlike its predecessor, the DFour, the D9100 is not compatible with Dura-Ace 9000, Ultegra, or 105 groupsets, though it is able to run Ultegra R8000 chainrings. With the exception of the difference in compatibility, the DFour91 includes all of the technology of the DZero packed into its spider, most importantly the power meter itself. The power meter saw some hefty reworking, with Quarq claiming 150 documented improvements, asserting leaps and bounds of advancement above previous models, with the most significant enhancements made to the strain gauges and measurement circuitry in the heart of the meter.

Gracing us with their presence again are Power Balance and Omnical. Power Balance records data to tell us our total output, and output for each leg individually, enabling us to better focus on a single side of the pedal stroke if needed. Omnical lets us swap rings when needed without the need for recalibration or impeding accuracy of our data. The DFour91 gives us total confidence with the use of any head unit thanks to both ANT+ and Bluetooth communication, unlike previous models that only used ANT+, meaning that its compatibility expands to pair with near any computer for seamless data transfer.

With all of the tech that's loaded into the DFour91, its no surprise that its topped off with the bells and whistles. It includes AxCad accelerometer, which provides cadence information, sans extra magnets and sensors to make sure you're not missing out on any additional data you crave. The system is compatible with a host of training programs, like Golden Cheetah, Strava, Training Peaks, and Training Peaks WKO+. The DFour91's Bluetooth compatibility also allows you to synch up to the Qalvin BLE app, enabling easy firmware upgrades, tuning, tweaking, and setting zero offsets.

If you're a returning Quarq-ateer, the key to upgrading is ensuring compatibility. To ensure you get the correct upgrade model, you can locate your current model on the chart included below.

  • Update your power meter for Dura-Ace9100 compatibility
  • Redesigned strain gauge boosts precision to next level
  • Individual power is measured for each leg with Power Balance
  • Broadcasts via ANT+ and Bluetooth for use with any head unit
  • Less correction required for better data and longer life
  • Charge the battery with ease, tool free
  • Install tool included for easy swapping
  • Please check chart below to ensure compatibility
Tech SpecsSize
Tech Specs
Arm Material
Compatible Components
[power meters and cranksets on 8-bolt since release] Quarq ELSA RS, Quarq Riken AL, Quarq Prime Power Ready Cranksets, SRAM Red Power Ready Cranksets, SRAM XX1 Power Meter, SRAM RED BB386 EVO standard crankset (Note: Boost spiders should not be paired with 156Q crank arms), [power meters switched to 8-bolt] Quarq Riken R (revision AEQ onward, except warrant/replacement - Jul '15), SRAM RED (eTap graphics - Jan '16)
Recommended Use
Manufacturer Warranty
2 years


DZero Power Meter Spiders
 Quarq PrimeElsa RS
August, 2014
Riken R
July, 2015
Rike AL
April, 2015
January, 2016
August, 2014
SRAM 10- or
Most 10- or
Mountain with
104 BCD
Shimano 11-Speed
(hidden bolt)




(non-hidden bolt)





    yes yes    


XX1 Eagle           yes     yes  
XX1 Eagle Boost           yes (168 Q-factor only)     yes  

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