• Products
  • Product Overview
  • Quarq ELSA 10R
  • Quarq RIKEN 10R
  • Quarq for Specialized
  • Quarq for Cannondale
  • SRAM RED 22 Power Meter
  • SRAM RED Quarq Power Meter
  • Qalvin
  • Product Archive
• Store
• Dealers
• Coaches
• Int'l
• Q-Blog
• Support
  • FAQ
  • Bottom Bracket - Frame Compatibility
  • Manuals & Downloads
  • Troubleshooting
  • Ring Calibration Tables
  • Qalvin
• About
• Contact

We are not currently accepting sponsorship requests. We will make an announcement on our web site when this changes.

USA and Canada: Purchase one from the Web Store under Magnets.
International customers: Contact your local SRAM Dealer.

USA and Canada: Use the Contact form, and be sure to include the following:

• A description of the part you need: Battery lid
• Name:
• Power Meter Serial Number:
• Address: Street/City/State/Zip/Country
• Email:
• Phone:

International customers: Contact your local SRAM Dealer.

Yes. You must return the entire power meter to the factory in Spearfish. We will perform the changeover, install a standard (non-power meter) spider on your original crank arms and return both to you. Your power meter will be inspected and calibrated. You will be charged for the new crank arms and must pay for shipping both ways. Contact our customer service team to get started.

Quarq and SRAM BB30 power meters work with BBright frames. You must remove the pre-load adjuster and small spacer from the spindle, and reassemble the crank with the wave washer against the non-drive arm, and the large 13mm spacer on the drive side. The wave washer is included with the PressFit30 bearing assembly kit. Contact our customer service team for an instruction sheet.

No. We cannot fit power meters to existing cranksets.

Quarq's ELSA 10R and RIKEN 10R power meters use 10-speed chainrings and can be fitted with alternative chainrings of your choice.

We have customers successfully using the following chainrings on Quarq power meters with 11-speed drivetrains:

• Rotor Q and No-Q in 130 BCD and 110 BCD
• Stronglight CT2 in 130 BCD only
• FSA Pro Road in 130 BCD and 110 BCD
• Wick Werks in 130 BCD and 110 BCD

Quarq products are sold in the Web Store, by phone, by authorized Dealers and by SRAM dealers worldwide.

Product support comes from the Quarq headquarters in Spearfish, South Dakota, via phone, email and this web site, and through authorized SRAM dealers worldwide.

Quarq offers a two-year warranty.

Quarq power meters are designed, manufactured and assembled in Spearfish, South Dakota. Final calibration, quality control and shipping also takes place in Spearfish, South Dakota.

ANT+ is a 2.4 GHz wireless network with standardized communication between devices including power meters, speed sensors, cadence sensors and heart rate straps. ANT+ enables manufacturers to independently develop sensors and computers. Riders can combine their favorites to create a system that meets their needs.

Please refer to our Bottom Bracket Page.

Yes. Please refer to our Bottom Bracket Page.

Quarq ELSA 10R and RIKEN 10R, and SRAM RED, have +/- 1.5% accuracy.

We believe the crankset spider is the best place on the bike to measure power because all drive torque flows directly through the spider and can be measured with great precision.

Quarq's latest power meters use five strain gauges in a proprietary arrangement that rejects out-of-plane loads.

A magnet delivers perfect repeatability for cadence events. Our own studies show accelerometers are not as precise and introduce a margin of error on top of measured strain. Quarq power meters are accurate to +/- 1.5% and at this point in time a magnet is integral to maintaining that accuracy.

Quarq power meters are highly engineered and feature multiple temperature compensation systems. From the intrinsically balanced strain gauge arrangement to clever measurement circuit design, temperature effects are isolated and eliminated at every step in the system.

Quarq power meters sample torque in a 60Hz macro-sample, each of which is composed of many sub-samples bringing the total sampling frequency to over 5000Hz. All of these samples are averaged for each discreet pedal revolution and reported to the head unit over the industry standard ANT+ protocol. i.e. If you are pedaling at 90rpm, power data will be received by the head unit every two-thirds of a second. Current generation ANT+ head units display and store power data once per second.

Each power meter is individually calibrated at the factory. Quarq's in-house validation and verification techniques use both static and dynamic testing.

The slope is a multiplier used to convert pedaling force into newton meters of torque and, ultimately, into the watts you see on your head unit. When Quarq says "calibrate" we mean a routine that sets the slope. The Calibrate command in Garmin head units sets the zero offset and should be called Zero Offset or User Zero Offset. Think of the zero offset as a "tare" - like zeroing a kitchen or bathroom scale. Setting the zero offset does not set or change the power meter's slope.

For the most accurate data, we recommend that you zero your power meter before each ride. The procedures for automatic and manual zeroing are described in the Quarq Power Meter User Manual. This is how they work:

Manual Zero (e.g. Garmin Calibrate command) - The power meter samples torque at 60 Hz for two seconds (120 measurements) and averages the result. The inverse of the result becomes the new zero offset.

Auto Zero - When you pedal backwards the power meter samples torque at 60 Hz and averages the measurement, and this average is stored. The power meter then sets the zero offset as the inverse average of the last 4 reverse revolutions. Note: To completely reset the zero offset with Auto Zero you must pedal backwards at least 4 times.

If you are replacing worn rings with a new pair of the same model, no recalibration is necessary. If you are swapping from Road to TT or Road to CX rings, or Brand X to Brand Y, or converting to a single speed with or without a bash guard, recalibration is highly recommended. You can do this using an accurately measured weight and Qalvin's Calibrate Slope routine. If you do not have access to Qalvin, you can return the power meter to Quarq for inspection and factory calibration.

"Quarq" is just a hiply misspelled word. A quark is a subatomic particle (which, by the way, is really fast). The word "quark" originated from the 1939 novel "Finnegans Wake" in the line:

Three quarks for Muster Mark!
Sure he hasn't got much of a bark
And sure any he has it's all beside the mark.

Physicist Murray Gell-Mann enjoyed the allusion to three quarks and applied the term to physics, as the Standard Model predicts three generations of elementary particles.

Quarks can have one of two fractional electric charges (+2/3 or -1/3), yielding six "flavors": Up, Down, Strange, Charm, Bottom, and the elusive Top quark.

Top and Bottom were originally called Truth and Beauty, but that got a bit lame after the Truth quark proved difficult to find and folks started saying "the quark model has no truth". This didn't go over so well in some circles, so Top and Bottom became the preferred terminology.