Black Friday power meter on sale

Power sensor on Black Friday: start from your crankset

Here, the measurement is done at the crankset. Three setups exist: a left crank equipped with gauges, which replaces yours on a Shimano crankset; a power spider, placed between the right crank and the chainrings; a complete crankset supplied with its measurement. Note the brand and series of your crankset, its axle, 24 mm for Shimano or DUB for Sram, the length of the cranks, and for a spider, the bolt circle diameter of the chainrings, 107 or 110 mm for example.

Discounted sensor: one base, several versions

A discount on a power sensor can only be assessed with the same setup: the crossed-out price and the displayed price must refer to the same measurement, one or two legs, the same length and the same tooth counts. At INPEAK, the crank of the Shimano 105 FC-R7100 is available in left-side Powercrank, USB-rechargeable Powercrank-E, and TWIN2, which measures each leg. At Sram, the Rival D1 Quarq is sold in 170, 172.5 or 175 mm, in a double chainring of 48-35 or 46-33, or in a single chainring of 40 teeth. Also, read the abbreviations in the titles: “S/Bb” or “Bb N.I.” refer to a crankset sold without a bottom bracket, to be picked from the bottom brackets in Black Friday. Finally, check that there's enough space between the equipped crank and the rear end.

One or two legs, and where to read your watts

A left-side measurement doubles the effort of that leg: it is suitable for zone training if you consistently use the same sensor. A spider integrates the effort from both legs without distinguishing them, while a dual-sided measurement separates left and right. Sensors communicate in ANT+ or Bluetooth with a computer, watch, or home trainer app. To change bikes without dismounting, check out the pedals on Black Friday, some of which measure power. For the rest of the year, the page for power sensors details each technology; models replaced by a new version often join the clearance.

Which brands of power sensors?

INPEAK, a brand developed in Poland, installs its sensor on Shimano cranks of original quality: 105, Ultegra and Dura-Ace for road, GRX for gravel, SLX and XT for mountain biking.

Sram integrates the measurement into its AXS cranksets, from Rival to Red, and into mountain biking with the XX SL Powermeter crankset designed for its Eagle T-Type drivetrain.

Quarq, a subsidiary of Sram specializing in power measurement, is present with XX1 Eagle Boost cranksets with a single 32-tooth chainring for mountain biking.

Frequently Asked Questions

Button cell or rechargeable battery: what to choose?

A button cell can be changed in a few seconds, provided you keep one on hand. A rechargeable battery, like that of the INPEAK Powercrank-E, avoids this purchase and recharges via USB cable between rides.

Is a measurement on only the left leg accurate enough?

It assumes equal effort from both legs, which varies with fatigue. To track progression, the consistency of the sensor matters more; the dual measurement primarily serves to monitor an imbalance.

Do you need to calibrate a power sensor?

Reset from your computer before riding, the crankset at rest, especially after a temperature change: it corrects gauge drift.

Do discounts on power sensors last after Friday?

The Black Friday retains its Friday, the one following Thanksgiving, but at Vélo-Store, its discounts on sensors last all November. Enough time to check your crankset's axle and length before deciding between crank, spider, or complete crankset.

What else do you need besides a crankset with a sensor?

The suitable bottom bracket for your frame if it’s not provided, compatible chainrings if you buy a spider on its own, and sometimes a mounting tool. An equipped left crank replaces the old one without any other parts.