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4iiii PRECISION 3+ Shimano R7100 Power Meter
August 15, 2025$349.99
4iiii’s PRECISION 3+ power meter for Shimano R7100 cranksets
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4iiii PRECISION 3+ Shimano R7100 Power Meter
The 4iiii PRECISION 3+ Shimano R7100 Power Meter is the perfect upgrade for riders with Shimano 105 7100 cranksets. This 4iiii power meter replaces your current left-side crank arm. It measures the power that is generated by your left leg and doubles it to determine your total watts.
4iiii uses patent pending 3-D tri-axial strain gauge technology in order to achieve +/- 1.0% accuracy, which places it among the most accurate power meters available. When it comes to weight, there is no equal. The 4iiii PRECISION sensor weighs a mere 9 grams – practically nothing! In addition, the power meter features dual ANT+ and Bluetooth SMART compatibility so you can use it with a wide range of devices. The 4iiii PRECISION Shimano R7100 Power Meter is one of the most accurate, lightweight and affordable direct force power meters available!
Product Details
Key Features of the 4iiii PRECISION 3+ R7100 Power Meter
- +/- 1 .0% accuracy: Uses patented technology to ensure precise power data, regardless of pedal stroke.
- Compact Design: Only 5.5 mm thick and 9 grams means it fits most frames and adds minimal weight.
- Apple Find My Integration: Offers piece of mind with native iOS tracking.
- 800 Hour Battery Life: Ultra-long battery life means replacement is rare.
Power Measurement
This 4iiii power meter measures left leg power and doubles the value to account for both legs (assumes both legs are generating the same force).
Compatibility
This power meter is compatible with Shimano R7100 cranksets. It can also be installed on other Shimano road cranksets, as long as they use Shimano’s Hollowtech II interface. See Compatibility tab for more information.
Considerations
The 4iiii PRECISION 3+ R7100 Power Meter measures power only from your left leg which means total power is estimated by doubling the left leg’s output. While this works well for many riders, it may be less accurate if there is a strength difference between your legs. This is common with single-sided power meters and worth considering if precise total power is your priority.
Advice From Our Staff
We believe this power meter is great for riders who want reliable power data and security without buying a full crankset. We feel it is a great upgrade if you already have a 105 R7100 crankset as it is easy to install, offers accurate power data and has very good battery life.
Options For This Power Meter
Crank arm lengths: 165 mm | 170 mm | 172.5 mm | 175 mm
Compatibility
Crankset: This 4iiii power meter is compatible with Shimano R7100 cranksets.
Please note, the power meter can also be installed on other Shimano road cranksets, as long as they use Shimano's Hollowtech II interface. These cranksets can easily be identified by the two opposing pinch bolts that are used to secure the left side crank arm. Please see the image below and contact us if you have any questions on compatibility.
Check Frame Clearance: Crank-arm based power meters attach a sensor on the inside of the left crank arm. On some bikes, there is not enough room between the left crank arm and the chainstay for the sensor to clear the frame. Therefore, you should make sure you have at least 8 mm of clearance for the PRECISION 3+. Also, make sure that you don't have a bottom bracket mounted rear brake (used on some aero and TT bikes). The important area to measure is right in the middle of the crank arm. Please refer to the image below.
If you find that your clearance is close but not quite sufficient, what many people will do is simply install a 1 or 2 mm bottom bracket spacer (between the left crank arm and the frame). This should provide you with the clearance you need.
4iiii PRECISION 3+ R7100 Specs
| Name | 4iiii PRECISION 3+ R7100 |
| Bike Type | Road |
| Location of Power Measurement | Crank Arm |
| Left or Both Legs Measured | Left only |
| Independent Left/Right Measurement | No |
| Installation | Easier |
| Crank Arm Material | Aluminum |
| Communication Protocol | ANT+ and Bluetooth SMART |
| Claimed Accuracy | +/- 1.0% |
| Automatic Temp. Compensation | Yes |
| Weight | 9 grams (sensor) |
| Battery Type | CR2032 coin cell |
| Battery Life | 800 hours |
| Method of Cadence Measurement | Accelerometer |
| Warranty | 3 years |
In the Box
- 4iiii PRECISION 3+ Shimano R7100 Power Meter
- CR2032 coin cell battery
Tools Needed for Installation
You will need the following tools for installation of this product. You can purchase many of these commonly used tools in our store.
Q&A
Have a question about this? Ask the staff.
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