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4iiii PRECISION 3+ Shimano XTR M9100 Power Meter

Josh Matthew May 23, 2024


4iiii power for your Shimano’s XTR M9100 or M9120 crankset!

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4iiii PRECISION 3+ Shimano XTR M9100 Power Meter

The 4iiii PRECISION 3+ Shimano XTR M9100 Power Meter is brings power to your M9100 or M9120 crankset. The 4iiii PRECISION power meter is a left-only crank arm-based power meter and replaces your current left side crank arm. It takes the power that is generated by your left leg and doubles it in order to determine your total power output.

Using 3D power meter technology capable of measuring tri-axial strain, the 4iiii XTR M9100 Power Meter is accurate to +/- 1.0%. In addition, it’s very lightweight, adding only 9 grams of weight to your crankset.

It features 800 hours of battery life and is compatible with both ANT+ and Bluetooth SMART devices. This means it’s compatible with your favorite bike computer, smart phone or tablet.


Key Product Details


This power meter is compatible with XTR M9100/9120/9130 cranksets. It is also compatible with all other Shimano x100/x120/x130 series MTB cranksets such as the XT M8100/M8120/M8130 or the SLX M7100/7120/7130. 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 XTR M9100 PRECISION 3+!

The all new 4iiii XTR M9100 PRECISION 3+ power meter features the following improvements over the version 2:

  • Apple Find My which allows you to always know where your bike is!
  • 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:

Affordable, 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, easy to install, 3-year warranty. See Specs tab for more information.

Advice From Our Staff:

4iiii left side crank arms are some of our best-selling units. They are affordable and easy to install. The one consideration is they only measure left leg power compared to some other power meters that measure power from both legs (those versions usually cost more however).


Options For This Power Meter

Crank arm lengths: 170 mm | 175 mm


Other Versions to Consider

Dual-Sided XTR 9100/9120 Crankset: We also sell the 4iiii PRECISION PRO Shimano XTR 9100/9120 Dual-Sided Power Meter which is a complete crankset. It is more expensive, however it measures power from both legs.


Crankset: The 4iiii power meter is compatible with XTR M9100/9120/9130 cranksets. It is also compatible with all other Shimano x100/x120/x130 series MTB cranksets such as the XT M8100/M8120/M8130 or the SLX M7100/7120/7130.

It is not compatible with x000 series cranks such as the XTR M9000, XT M8000 or SLX M7000.

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.

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

4iiii PRECISION Shimano XTR M9100 Specs

Name4iiii PRECISION XTR M9100
Bike TypeMTB
Location of Power MeasurementCrank Arm
Left or Both Legs MeasuredLeft only
Independent Left/Right MeasurementNo
Crank Arm MaterialAluminum
Communication ProtocolANT+ and Bluetooth SMART
Claimed Accuracy+/- 1.0%
Automatic Temp. CompensationYes
Weight210 grams (170 mm)
Battery TypeCR2032 coin cell
Battery Life800 hours
Method of Cadence MeasurementAccelerometer
Warranty3 years

In the Box

  • 4iiii PRECISION 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.

  • 8 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


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