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INPEAK POWERCRANK-E Shimano GRX FC-RX810 / RX820 – rechargeable power meter
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€359.00
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Shimano GRX FC-RX810 / FC-RX820 left crank arm with integrated INPEAK POWERCRANK-E power meter. Left-side measurement with ±2% claimed accuracy, rechargeable battery with up to 90 hours of runtime, ANT+ / Bluetooth and IP67 protection. A particularly relevant solution for adding power measurement to a GRX gravel bike without replacing the crankset, chainrings or bottom bracket.
Arm length
INPEAK · POWERCRANK-E · GRAVEL
INPEAK POWERCRANK-E Shimano GRX FC-RX810 / RX820
The POWERCRANK-E Shimano GRX FC-RX810 / FC-RX820 allows you to add power measurement to a gravel bike already fitted with a Shimano GRX crankset, without unnecessarily changing the rest of the setup. The INPEAK sensor is integrated into a genuine Shimano GRX left crank arm and transmits power, cadence and pedalling data via ANT+ and Bluetooth Low Energy.
MEASUREMENT
Left-side only
BATTERY LIFE
Up to 90 h
ACCURACY
Claimed ±2%
CONNECTIVITY
ANT+ + Bluetooth
Velo-Perso.com’s opinion
GRX is a hybrid groupset designed for both road-like riding and rougher terrain. In gravel riding, part of the rider’s effort is also used to control, guide and stabilise the bike on uneven surfaces: body movements, traction changes, repeated accelerations and rough sections do not always translate directly into higher power at the crank. At a similar overall effort level, it is therefore entirely possible for your gravel power curve to be lower than your road power curve.
From that perspective, having power measurement on the left crank arm only is not really a drawback for this type of use. The main objective is to compare your gravel rides with other gravel rides, manage your pace more effectively and monitor progress using a consistent reference, rather than trying to compare road and gravel data watt for watt.
Thanks to its easy installation, integrated rechargeable battery and direct integration into a Shimano GRX crank arm, the INPEAK POWERCRANK-E GRX is, in our view, a very competitive, simple and genuinely useful product.
Why this power meter makes particular sense on a GRX gravel bike
A gravel bike already equipped with Shimano GRX has a crankset specifically designed for this type of riding. If the crank length, gearing and bottom bracket already suit you, there is no need to replace the complete crankset simply to gain access to power data.
INPEAK’s approach is very straightforward: only the left crank arm is replaced with a Shimano GRX crank arm fitted with the POWERCRANK-E sensor. The right crank arm, chainrings, axle and bottom bracket remain unchanged. Installation is quick and the bike retains an appearance very close to the original GRX setup.
For pacing
Displaying smoothed power helps prevent overly hard starts, manage long climbs more effectively and control your effort despite changing surfaces.
Displaying smoothed power helps prevent overly hard starts, manage long climbs more effectively and control your effort despite changing surfaces.
For monitoring progress
Compare your performance on similar roads, trails, climbs and segments using the same power meter as a consistent reference.
Compare your performance on similar roads, trails, climbs and segments using the same power meter as a consistent reference.
For structured training
Power, cadence, training zones and workload become available without having to redesign the bike.
Power, cadence, training zones and workload become available without having to redesign the bike.
→ Read our guide: how to use a power meter according to your rider profile
Single-sided measurement: what it actually measures
The POWERCRANK-E SINGLE measures deformation of the left crank arm, then estimates total power from the contribution of that leg. INPEAK claims ±2% measurement accuracy for the sensor itself.
As with all single-sided systems, a natural imbalance between the left and right legs may create a difference between estimated power and the rider’s true total power output. For gravel training and performance monitoring, this is generally secondary as long as you consistently use the same system as your reference.
On rough terrain, it is also important to distinguish the mechanical power transmitted through the crankset from the rider’s total physical effort. Part of the energy expenditure is used to control and stabilise the bike. A dual-sided system would not eliminate this effect: it would measure the contribution of both legs more precisely, but it would still not measure the work performed by the upper body.
Shimano GRX RX810 / RX820 compatibility
This version is offered by INPEAK for Shimano GRX FC-RX810 and FC-RX820 cranksets. It therefore covers the main high-end GRX 11-speed and 12-speed generations while allowing you to keep the rest of the crankset already fitted to the bike.
Check before ordering: choose the same crank length as your current setup and make sure there is sufficient clearance between the INPEAK module, located on the inside face of the left crank arm, and the left chainstay of the frame. This check is particularly important on gravel frames with wide chainstays.
If you are unsure about your crankset, crank length or available frame clearance, Velo-Perso can check compatibility before you order.
Integrated rechargeable battery: up to 90 hours
POWERCRANK-E uses an integrated 110 mAh rechargeable Li-Po battery. INPEAK claims up to 90 hours of use and approximately 2 hours for a full charge. Charging is carried out with the supplied magnetic USB cable.
The sensor features a low-battery notification, automatic sleep mode and automatic wake-up. For a bike used regularly, this architecture avoids repeatedly opening a battery compartment and keeps everyday maintenance very simple.
Technical specifications
| Measurement type | Single-sided, left crank arm |
| Compatible cranksets | Shimano GRX FC-RX810 / FC-RX820 |
| Claimed accuracy | ±2% |
| Power range | 20 to 2000 W |
| Cadence range | 20 to 200 rpm |
| INPEAK device weight | Approx. 10 g added to the crank arm |
| Water resistance | IP67 |
| Operating temperature | -5°C to +50°C |
| Temperature compensation | Yes, automatic compensation |
| Internal sensors | Gyroscope + accelerometer |
| Data | Power, cadence, Torque Effectiveness, Pedal Smoothness |
| Connectivity | ANT+ and Bluetooth Low Energy |
| Battery | Rechargeable 110 mAh Li-Po |
| Battery life | Up to 90 h |
| Charging time | Approx. 2 h from 0 to 100% |
| Charging | Magnetic USB cable included |
| Firmware updates | INPEAK MANAGER app |
| Zwift compatibility | Yes |
GRX, gravel and your power curve: compare like with like
On smooth roads, a large proportion of the rider’s effort is directly devoted to producing power through the crankset. On gravel, the riding surface changes this relationship: the bike moves more underneath the rider, traction varies, certain sections require unloading the saddle or pedals, and the upper body works harder.
For this reason, we do not recommend interpreting a gravel power curve as a simple copy of your road power curve. The most useful approach is to gradually build your own gravel-specific benchmarks: power on an off-road climb, 5-minute or 20-minute efforts, consistency during long efforts, FTP development and training load over the season.
This is precisely where the simplicity of a left-only crank power meter makes sense: a consistent and repeatable sensor, used ride after ride, already provides the key information required to pace and compare your efforts.
→ Compare INPEAK, Rotor and the main power meter architectures
INPEAK or a complete power meter crankset?
| INPEAK POWERCRANK-E GRX | Complete power meter crankset | |
|---|---|---|
| Priority | Add power measurement to an existing GRX setup | Upgrade the complete crankset |
| Installation | Replace the left crank arm only | Crankset, axle and sometimes bottom bracket may need changing |
| Measurement | Single-sided, left | Depending on the system: axle, spider or dual-sided |
| Main advantage | Simplicity, controlled cost, original setup retained | Also change crank length, weight, gearing or architecture |
At Velo-Perso, we therefore consider INPEAK and Rotor to be two complementary approaches: INPEAK when the existing Shimano GRX crankset already suits the rider, and a complete system when the goal is also to upgrade the crankset as a whole.
European design and long-term support
INPEAK designs and manufactures its power meters in Poland. For an electronic product intended to remain on the bike for several seasons, this European proximity is valuable in terms of supply, updates, technical support and after-sales service.
POWERCRANK-E firmware can be updated using the INPEAK MANAGER app. The system also allows Scale Factor adjustment and zero calibration, and includes automatic temperature compensation.
Available crank lengths
| Length | Reference | EAN |
|---|---|---|
| 170 mm | PCV40SHG8270B | 5907465631808 |
| 172.5 mm | PCV40SHG8272B | 5907465631792 |
| 175 mm | PCV40SHG8275B | 5907465631785 |
What is included
- Shimano GRX left crank arm with integrated INPEAK POWERCRANK-E SINGLE power meter
- 2 m magnetic USB charging cable
- Device data card with PIN code for the mobile app
- User manual
- Sticker set
Why buy your INPEAK power meter from Velo-Perso?
Compatibility expertise
We look at crankset, crank length, bottom bracket, frame and drivetrain — not just a product reference.
We look at crankset, crank length, bottom bracket, frame and drivetrain — not just a product reference.
Technical advice
We can tell you when an INPEAK crank arm is all you need and when a complete power meter or crankset is the more relevant option.
We can tell you when an INPEAK crank arm is all you need and when a complete power meter or crankset is the more relevant option.
European support
INPEAK designs and manufactures in Poland: useful proximity for the long-term support of an electronic cycling product.
INPEAK designs and manufactures in Poland: useful proximity for the long-term support of an electronic cycling product.
In short
For a gravel bike already well equipped with Shimano GRX RX810 or RX820, POWERCRANK-E adds reliable power data with minimal changes: one crank arm, a rechargeable battery, a consistent power reference and a setup that remains fully GRX.
For a gravel bike already well equipped with Shimano GRX RX810 or RX820, POWERCRANK-E adds reliable power data with minimal changes: one crank arm, a rechargeable battery, a consistent power reference and a setup that remains fully GRX.
Power meter guide · Power meter comparison · Rotor alternatives
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