-€80.00
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INPEAK POWERCRANK Shimano Ultegra FC-R8100 CR2032 Battery Power Meter
Reduced price:
€309.00
Tax included
himano Ultegra FC-R8100 left crank arm with integrated INPEAK power meter. Replaceable CR2032 battery, up to 200 h runtime, ±2% claimed accuracy, ANT+ / Bluetooth and five lengths from 160 to 175 mm. Add watts without replacing your crankset.
Arm length
INPEAK · POWERCRANK · CR2032 BATTERY
Shimano Ultegra FC-R8100: add power data, not a new crankset
The INPEAK POWERCRANK Ultegra FC-R8100 left crank arm adds power measurement to your existing Shimano crankset. A discreet, dependable and more affordable alternative to the rechargeable model, letting you train with watts without replacing the rest of your drivetrain.
±2%Claimed accuracy
200 hMaximum CR2032 runtime
ANT+ / BLECompatible head units and apps
160–175 mmFive crank lengths
The coin-cell version makes power measurement more accessible without sacrificing a well-engineered system. It is a smart choice for riders on a tighter budget who want to upgrade an Ultegra R8100 crankset while keeping the components that already work well. The selection of crank lengths is another advantage: it makes replacing a left arm straightforward and may, in specific circumstances, allow different left and right arm lengths—for example after an injury—provided a qualified bike fitter or healthcare professional has assessed the setup.
Why choose the CR2032 POWERCRANK?
Keep the upgrade affordable
Only the left crank arm is replaced. Your right arm, chainrings, axle and bottom bracket remain on the bike, so you do not need a complete crankset just to see your power output.
Simple battery replacement
A standard CR2032 powers the sensor. INPEAK claims up to 200 hours of riding time. No charging cable is required: replace the battery when needed.
Useful training data
Track power, cadence, FTP, training zones and climbing efforts. ANT+ and Bluetooth Low Energy support pairing with compatible head units and apps.
Integrated, weather-resistant design
The sensor is fitted to an original Shimano Ultegra left arm. IP67 ingress protection, temperature compensation and minimal added weight make the upgrade unobtrusive.
Five crank lengths: 160, 165, 170, 172.5 and 175 mm
Length choice is a genuine benefit of this model. Match your existing setup or select a length recommended for your riding position, taking the necessary fit adjustments into account.
Different left and right lengths? In specific situations, including after an injury, a professionally assessed setup may use different crank lengths on each side. This is not a change to make casually: biomechanics and bike fit need to be considered. Remember that the POWERCRANK SINGLE measures left-leg force and extrapolates total power; a substantial left/right strength imbalance can affect the resulting estimate.
Single-sided power measurement: what it means
The sensor measures torque from the left leg and doubles it to estimate total power. This cost-effective method works well for many riders managing endurance sessions, pacing climbs and tracking fitness over time. It does not independently measure right-leg power or provide true left/right balance data.
For meaningful long-term comparisons, consistent measurements with the same sensor often matter more than matching the exact watt figure displayed by a trainer or a different meter.
Compatibility and fitting: three checks
- Crank model: intended for the Shimano Ultegra FC-R8100 crankset (24 mm Hollowtech II axle). Check the actual crank model, not just the groupset name.
- Length: choose 160, 165, 170, 172.5 or 175 mm to suit your bike fit.
- Frame clearance: check the space between the sensor on the inner face of the arm and the left chainstay. INPEAK advises checking for approximately 8 mm clearance at the relevant position.
Installation replaces the existing left crank arm. Follow Shimano assembly instructions and torque specifications, and perform the recommended zero-offset procedure after installation or a battery change.
Technical specifications
| Product | Shimano Ultegra FC-R8100 left crank arm with INPEAK POWERCRANK SINGLE |
|---|---|
| Measurement | Left side; estimated total power |
| Claimed accuracy | ±2% |
| Power range | 20–2,000 W (manufacturer specification) |
| Cadence range | 20–200 rpm |
| Wireless | ANT+ / Bluetooth Low Energy |
| Power supply | One replaceable 3 V lithium CR2032 cell |
| Claimed runtime | Up to 200 hours of use |
| Added weight | Approximately 10–12 g for the sensor, depending on reference method |
| Ingress protection | IP67 |
| Operating temperature | -5°C to +50°C |
| Features | Temperature compensation, zero offset, torque effectiveness, pedal smoothness, automatic wake/sleep |
| App | INPEAK MANAGER for firmware updates and settings |
| Lengths | 160 / 165 / 170 / 172.5 / 175 mm |
Replaceable battery or rechargeable?
| CR2032 POWERCRANK | Rechargeable POWERCRANK-E | |
|---|---|---|
| Power supply | Replaceable coin cell | Rechargeable battery |
| Claimed runtime | Up to 200 h | Up to 90 h |
| Main benefit | Lower entry cost, simplicity | Recharge without disposable cells |
| Measurement | Left side, ±2% | Left side, ±2% |
Both versions let you retain your Ultegra crankset. The CR2032 model is not a lower-quality meter; it simply offers a different power supply and price positioning.
Frequently asked questions
Do I need to replace my complete Ultegra crankset?
No. Only the compatible FC-R8100 left crank arm is replaced; the right arm, chainrings and bottom bracket remain in place.
Does this meter measure both legs?
No. It measures left-side power and estimates the total. It does not independently measure right-leg power.
How is it different from POWERCRANK-E?
POWERCRANK uses a replaceable CR2032 cell with up to 200 hours of claimed runtime. POWERCRANK-E has a rechargeable battery with up to 90 hours of claimed runtime.
Can I use different crank lengths left and right?
This may be possible in a professionally assessed setup, for example after an injury, but should not be attempted without specialist bike-fit guidance. A left-only sensor does not account for genuine left/right power asymmetry.
Can I ride in the rain?
The sensor housing is rated IP67. Ensure that the seal and battery cover are correctly installed whenever replacing the cell.
Already riding Ultegra R8100? Keep it.
Choose your crank length and add power measurement with an INPEAK left crank arm. Need help checking frame clearance or a specific fitting arrangement? Contact Velo-Perso before ordering.
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