4.9 / 5.0

4iiii Shimano XT M8100 Precision 3+

€389.99 RRP: €399.00

Prices incl. VAT plus shipping costs

In stock, delivery time 1-3 days.

Crank Length:

  • SW10872.1
The 4iiii XT M8100 Precision 3+ power meter is a single-sided powermeter for MTB cranks of the... more
4iiii Shimano XT M8100 Precision 3+

The 4iiii XT M8100 Precision 3+ power meter is a single-sided powermeter for MTB cranks of the Shimano M8100 series. It measures the power at the left crank arm. The 4iiii power meter is now available in the 3rd generation. The actual powermeter weighs in at only 9g and sits well protected inside the left crank arm. The widely used CR2032 battery lasts for a whopping 800 hours of operation of the powermeter. The measurement accuracy is ± 1%. For mounting the 4iiii Power L XT M8100 you need the TL-FC16 tool.

Highlights and Downsides

  • single-sided power measurement with high accuracy (± 1%)
  • 800h battery life with a CR2032
  • integrated cadence measurement
  • very low weight (adds only 9g to the crank arm)
  • automatic temperature compensation
  • easy to swap between bikes
  • compatible with all Shimano XT M8100 cranks
  • works with many bike computers and smartphones (ANT+ & Bluetooth)
  • 3-year manufacturer's warranty
  • Apple Find My feature
  • only left-sided measurement
  • compatible only with Shimano XT M8100 cranks (no M8000)
  • TL-FC16 tool needed for installation

Single-sided measurement

With the 4iiii Precision 3+ power meter, only the left crank arm is equipped with measurement electronics. The power is doubled to estimate the total power. Staying in your training zones or pacing a long climb or a triathlon usually works very well with a single-sided power meter. It becomes more difficult when one leg is significantly stronger than the other. Then the total power deviates. The 4iiii is therefore particularly suitable for riders who can do without the few last percent of accuracy.

Compatible bikes and cranks

The power meter is mounted on the inside of the crank arm. Therefore, 10mm space is required between the crank arm and frame. With direct-mount brakes it is often too tight. You can check with a 10mm allen wrench whether a 4iiii power meter fits onto your bike. In the power meter area, the 10mm allen wrench must fit between the frame and crank arm:

Stages Clearance Check

The Stages Shimano XT M8100 power meter fits not only to cranks of the same series. The M8000 series is not compatible.

Compatible bike computers and smartphones

Thanks to ANT + and Bluetooth Smart, the 4iiii power meter is compatible with all ANT + enabled bike computers and smartphones with Bluetooth Smart technology. With Bluetooth Smart, the 4iiii power meter works with Zwift, TrainerRoad, Rouvy, The Sufferfest and other indoor-training apps.

Construction and design

The left-hand 4iiii power meter sits well protected in a flat plastic housing on the inside of the left crank arm. Not everyone has a perfect pedal stroke. The forces acting on the pedal crank change when you sit, stand to climb a steep hill, or sprint. In addition, the way your legs apply force to the pedals changes as you become fatigued. To ensure that the force applied to your crank is measured precisely, 4iiii uses a patented 3D strain gauge technology. Power is measured by lateral flex, pull and twist of the crank. Cadence is measured using accelerometers. The 4iiii Powermeter is permanently connected to the left crank arm. This is therefore always included in the pack. The 4iiii Powermeter has the water resistance class IPX7.


The 4iiii Shimano XT M8100 power meter is powered by a standard CR2032 button cell. A battery is sufficient for about 200 hours of operation time. The CR2032 is widely used and inexpensive. It is available at almost every supermarket. The battery can be changed without tools. The LED on the power meter provides information about the battery level.


The actually power meter has a low weight of just 9g and is the lightes power meter on the market.


We were able to confirm the accuracy of +-1% several times on our calibrated Cyclus II ergometer in the laboratory and in comparison with other power meters on the road. The measurement accuracy must be put into perspective somewhat, since the measurement is only one-sided.


The cadence is determined by means of an accelerometer and an integrated ring laser and transmitted to the bike computer or smartphone. An additional cadence sensor is no longer necessary.

Temperature compensation

When temperatures change, different materials expand differently. This can have a significant impact on the measurement accuracy of a power meter, as the strain gauges react to even the smallest changes. The 4iiii power meter therefore has active temperature compensation. This means that it delivers precise measurements even when temperatures change.


Each individual 4iiii power meter is individually calibrated at the factory. Something else is the zero calibration (also called "Zero Offset" or "Manual Zero"), which should be done before every ride. This is similar to a scale that also "zeros" itself before weighing. For zero calibration, the 4iiii power meter must be active and connected to the bike computer or smartphone. The zero calibration can be performed on the bike computer or smartphone.

Setup / Firmware Updates

Unlike other power meters, the 4iiii power meter does not need to be specially set up or registered. The correct crank length is already stored in the power meter. Firmware updates require the 4iiii App (Android & IOS) and a smartphone. We recommend always using the latest firmware of the power meter and the cycling computer.


The installation of the 4iiii power meter is very simple. The left crank arm of your crank is simply replaced by the 4iiii crank arm. For the 4iiii Shimano XT M8100 power meter you need a 5mm allen wrench and the Shimano TL-FC16 crank assembly tool. It's needed to loosen or tighten the bolt that pulls the left crank onto the axle.


We have made good experiences with the durability of the 4iiii power meter. Due to its placement on the inside of the left crank, the power meter is well protected against mechanical influences. In a crash, for example, a pedal power meter usually gets somewhat beaten up. This is where the 4iiii can score.

Apple Find My

The peace of mind of knowing exactly where your bike is, wherever you go.

Warranty and support

The 4iiii power meter comes with a 3 manufacturer's year warranty. The 4iiii power meters are manufactured in Canada. 4iiii also has European distribution in the Netherlands. If there is ever a problem, we have a direct line to 4iiii Europe and can help you quickly.


Sensor Location:

left crank arm


± 1%


adds 9gr to left crank arm

Battery Life:

about 800 hours (CR2032)

Battery Replacement:

Tool free

Wireless Technology:

ANT+, Bluetooth Smart Ready

Operating Temperature:

0 to 50°C

Storage Temperature:

-40 to 60°C

Firmware Upgrades:

yes, wireless

Compatible Software:

Training Peaks, Strava, Garmin Training Center and others

Power Range (Watts):

0 to 4000

Cadence range (rpm):


Crank Compatibility:

Shimano XT M8100

Available lengths:

170, 175mm

Active temperature compensation

Accelerometer based cadence measurement

In the pack

✔ 4iiii XT M8100 Precision 3+ power meter
✔ Left crank arm
✔ Battery
✔ Manual

Crank manufacturer: Shimano
Carbon or aluminum: Aluminum
Single or double sided: left side
Road or MTB: Road
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