Skip to main content

4iiii PRECISION Shimano Ultegra R8100 Single-Sided Crankset

Josh Matthew June 12, 2024

$639.99

4iiii left side power on a Shimano Ultegra 12-speed crankset!

Clear selection

4iiii PRECISION Shimano Ultegra R8100 Single-Sided Crankset

The 4iiii PRECISION Shimano Ultegra R8100 Single-Sided Crankset brings 4iiii left side power to Shimano’s new Ultegra 12-speed crankset! The 4iiii PRECISION 3 power sensor is accurate to +/- 1.0%, is lightweight and features an 800-hour battery life. The power meter is compatible with both ANT+ and Bluetooth SMART devices. This means you can use it with your favorite bike computer, smart phone or indoor training app.

Please note – this crankset measures left leg power only.

 

Key Product Details

Compatibility:

This power meter is compatible with 2×12 road drivetrains and 24 mm Shimano bottom brackets. Most customers that buy it already have a Shimano R8100 crankset on their bike and therefore, it’s an easy swap. However, it can be used on any road bike as long as its 2×12 with a 24 mm bottom bracket. See Compatibility tab for more information.

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).

New 4iiii R8100 PRECISION 3!

The all new 4iiii R8100 PRECISION 3 power meter features the following improvements over the version 2:

  • 800 hours of battery life – the longest coin cell battery life in a power meter on the market!
  • Sleeker, slimmer profile making most incompatibility issues a thing of the past.
  • Stronger antenna for even better connectivity.
  • Indicator light for battery life, successful zero-offset and when the unit has been turned on.

Key Features:

Accurate to within +/- 1.0%, lightweight at only 9 grams of added weight, 800 hours of battery life, CR2032 user-replaceable battery, ANT+ and Bluetooth compatible, 3-year warranty. See Specs tab for more information.

Advice From Our Staff:

This is a great option for customers with a Shimano R8100 drivetrain that want to keep an OEM R8100 crankset on their bike but add power. We also like that fact that this crankset has a 3-year warranty, which is longer than most power meters.

 

Other Versions to Consider

Dual-Sided R8100 Crankset: We also sell the 4iiii PRECISION PRO Shimano Ultegra R8100 Dual-Sided Crankset which is a complete crankset. It is more expensive, however it measures power from both legs.

Compatibility

Bottom Bracket: This power meter is compatible with 2x12 road drivetrains and 24 mm Shimano bottom brackets. Most customers that buy it already have a Shimano R8100 crankset on their bike and therefore, it's an easy swap. However, it can be used on any road bike as long as its 2x12 with a 24 mm bottom bracket.

Check Frame Clearance: Crank-arm based power meters like this one 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 between the left crank arm and the chainstay - and 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.

The clearance between the frame and left side power meter crank arm

4iiii Shimano Ultegra R8100 Power Meter Specs

Name4iiii PRECISION 3 R8000 Crankset
Bike TypeRoad
Location of Power MeasurementCrank arm
Left or Both Legs MeasuredLeft
Independent Left/Right MeasurementNo
InstallationMore involved (60 min. estimated)
Crank Arm MaterialAluminum
Communication ProtocolANT+ and Bluetooth SMART
Claimed Accuracy+/- 1.0%
Active Temperature CompensationYes
Weight9 grams (added weight)
Battery TypeCR2032
Battery Life800 hours
Method of Cadence MeasurementAccelerometer
BCD110 4-bolt asymmetric
Spindle Size24 mm
Q Factor146 mm
Warranty3 years

In the Box

  • 4iiii PRECISION Shimano Ultegra R8100 Single-Sided Crankset
  • 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.

  • Shimano Crank Arm Cap Tool
  • 5 mm Allen key

Common Questions and Answers

Question: How do I determine what length my current cranks are so I can make sure I get the same size?

  • Your crank arm length should be printed or stamped on the inside of the left crank arm, usually near the pedal end.

End of crank arm showing crank arm length

Reviews

There are no reviews yet.

Be the first to review “4iiii PRECISION Shimano Ultegra R8100 Single-Sided Crankset”

The maximum upload file size: 5 MB. You can upload: image, audio, video, document, spreadsheet, interactive, text, archive, code, other. Links to YouTube, Facebook, Twitter and other services inserted in the comment text will be automatically embedded. Drop file here

OTHER CUSTOMERS ALSO VIEWED

THIS PRODUCT IS FREQUENTLY BOUGHT WITH

Shopping Cart