Frequently Asked Questions

General Questions

What is "Quarq"?

"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.

How do I buy Quarq products?

Quarq products are sold on this web site, by phone, by authorized Dealers and by SRAM dealers worldwide.

What support do I get?

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

What is the warranty on Quarq products?

Quarq power meters have a two (2) year warranty.

Where are Quarq products manufactured and assembled?

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.

How do I get sponsored?

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

Power Meter Questions

WHAT IS ANT+™?

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.

HOW ACCURATE ARE QUARQ POWER METERS?

Quarq power meters have +/- 1.5% accuracy.

WHY DO YOU MEASURE POWER AT THE CRANKSET SPIDER?

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.

HOW MANY STRAIN GAUGES ARE IN THE POWER METER?

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

What are the differences between magnet- and accelerometer-based cadence measurement?

Accelerometer cadence offers convenience and was developed for bikes that have limited options for magnet placement.  Performance is excellent up to 160rpm and in all but the most extreme vibration environments - roadside rumble strips being the best example.

All Quarq power meters with an LED and CR2032 battery are compatible with accelerometer cadence.   Firmware v23 switches it on.  You can upgrade to firmware v23 using Qalvin.

Accelerometer cadence is automatically enabled when no magnet is present.  No user intervention is needed.

In terms of accuracy, single pedal stroke cadence accuracy decreases by a maximum of 2%, but cumulative accuracy is unaffected.  There is little or no impact on cumulative power values such as kilojoules, average power and normalized power.

Benchmark tests show the accuracy of Quarq’s accelerometer cadence matches or surpasses other products that use accelerometers for cadence.

A magnet remains the most precise method for cadence measurement.  It ensures that cadence is accurate no matter what the conditions.

DO QUARQ POWER METERS FEATURE TEMPERATURE COMPENSATION?

All Quarq power meters feature passive temperature compensation delivered by the strain gauge arrangement, circuit board design and electrical circuit. Quarq’s newest power meters - Quarq ELSA RS and SRAM XX1 - add a multipoint, active temperature compensation that enhances accuracy and consistency, making them our most precise power meters to date.

WHAT IS THE SAMPLING RATE OF QUARQ POWER METERS?

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 3500Hz. 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.

HOW ARE QUARQ POWER METERS CALIBRATED?

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

Support

WHERE CAN I BUY A NEW MAGNET?

USA and Canada: Purchase one from this web site under Products > Accessories. International customers: Contact your local SRAM Dealer.

I HAVE A BROKEN BATTERY LID. HOW DO I GET A REPLACEMENT?

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.

CAN I SWAP BETWEEN SRAM GXP AND BB30 CRANKSETS?

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.

WHAT OPTIONS DO YOU HAVE FOR BBRIGHT?

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.

CAN I INSTALL A POWER METER SPIDER ON MY SRAM CRANKSET?

No. We cannot fit power meters to existing cranksets.

I HAVE A SHIMANO CRANK. WHAT ARE MY OPTIONS?

Quarq's ELSA RS power meter was specially designed for Shimano's Hollowglide 11-speed chainrings.  Quarq's ELSA R and RIKEN R power meters use standard 130mm and 110mm bolt circle diameters and work with work with Shimano’s 7900 and 7950 10-speed chainrings (RIKEN R in 130BCD only).  ELSA R and RIKEN R also work with other aftermarket chain rings that use a 130 or 110 BCD including Rotor Q and No-Q, FSA Pro Road, Wick Werks and Stronglight (Stronglight in 130BCD only).

I HAVE AN 11-SPEED DRIVETRAIN. WHAT ARE MY OPTIONS?

The Quarq ELSA RS and SRAM RED 22 power meters are designed for Shimano and SRAM 11-speed groupsets.

WHAT POWER METER FITS MY BIKE?

Please refer to our Product Compatibility page.

DO YOU HAVE A LIST OF BIKE-SPECIFIC FITTING PROBLEMS OR SOLUTIONS?

Yes. Please refer to our Product Compatibility page.

WHAT DO CALIBRATION, SLOPE AND ZERO OFFSET MEAN?

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.

WHAT PRE-RIDE ZEROING IS REQUIRED?

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.

DO I NEED TO SEND IN MY SRAM S975 OR CINQO SATURN POWER METER IF I SWAP THE CHAINRINGS?

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.