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Get even more out of your Shimano Dura Ace - with the DFour91 power meter Spider by QUARQ
The DFour91 power meter was specially designed for the Shimano Dura Ace R9100 series and equips this groupset with the latest DZero platform by QUARQ. It is based on the QUARQ technology that has been developed over 10 years and has innovative features such as wireless two-channel data transmission via Bluetooth Low Energy (LE) and ANT+ or the Qalvin BLE app. If you already have a QUARQ power meter with an 8-bolt interface as a connection between spider and crank, you can upgrade it to DZero technology with the DFour91 power meter spider.
Information regarding the return of batteries and electrical equipment:
Find out more here.
Application: Road, Triathlon & Time Trial, Cyclocross
Type: spider with power measurement
Chainring Mount: 110 mm pitch circle, 4-arm asymmetrical
Series: DZero (DFour91)
Chainline: 45 mm
Tolerance: +/- 1.5 %
Power Source: CR2032 lithium battery
Battery Life: approx. 200 hours
Data Collected: power (dual-sided), cadence, torque, pedal stroke uniformity
Data Transfer: ANT+, Bluetooth
- QUARQ ELSA RS (as of August 2014)
- QUARQ RIKEN AL (as of April 2015)
- QUARQ Prime Power Ready cranks (as of March 2016)
- QUARQ RIKEN R (as of July 2015)
- QUARQ DFour91 power meters (as of 2017/18)
- SRAM Red Power Ready cranks (as of March 2016)
- SRAM Red BB386EVO standard cranks (as of March 2016)
- SRAM Red power meters (eTap® graphics as of January 2016)
- SRAM XX1 power meters (as of August 2014)
- not for QUARQ ELSA R
- for Shimano Dura Ace R9100 chainrings
- also compatible with Ultegra R8000 chainrings
- CNC-machined aluminium spider (power meter)
- 8-bolt interface (note compatibility)
- tool-free battery change
- automatic or manual zero setting
- LED status display
- standby after 10 minutes of inactivity, automatic restart by crank rotation
- no cadence magnet required thanks to AxCad (multi-axis acceleration sensor)
- 10K temperature compensation (programmed with over 10,000 data points)
- easy chainring change without recalibration
- Qalvin BLE app: installation, firmware updates, reset, battery status, system diagnostics
QUARQ Operating Principle
The crankset forms the heart of your bike. Their only task is to convert the force of both legs into forward motion - the perfect place to measure performance.
Power meters calculate power by measuring torque (pedal force) and angular velocity (cadence). Power = torque x cadence. When you pedal, all parts of the bicycle drivetrain shift (bend) slightly under the load. Power meters are designed using FE analysis so that these displacements take place in a very controlled manner and at specific locations in relation to the applied load. Strain gauges are used to measure this displacement and thus calculate the applied torque. Reed switches are used to calculate the cadence.
DZero is QUARQ's next generation power meter, named after the DZero Experiment, one of the most accurate and innovative scientific projects to discover subatomic particles. With a revised measurement loop, optimised strain gauge design, increased accuracy and the features of the Qualvin app, DZero represents the state of the art in power meter technology. You can choose between Bluetooth LE and ANT+ technology for data transfer. A simplified product line makes it easier for you to find the right power meter for your bike. Compatibility has been extended to include Boost 148 (52 mm chainline) for Mountain bikes and BB386EVO bottom brackets. Older QUARQ power meters can be upgraded to DZero technology with the DFour91 power meter spider, provided they have the 8-bolt interface as a connection between the crank and the spider.
The power measurement depends on the choice of the right chainring. Change from a Road to a Time Trial chainring without sacrificing accuracy. No recalibration necessary.
Shows the ratio of the generated power in the right drive stroke (first half) compared to the left drive stroke (second half). This allows you to pedal evenly with a 360 degree rotation.
Manufacturer Part Number:
- 1 x QUARQ DFour91 power meter spider
- 1 x battery
- black/110 mm: 154 g