4iiii RX810 GRX NDS Precision 3 Power Meter

The 4iiii RX810 GRX NDS Precision 3 is the successor to the Precision. In the Precision 3, the sensor is smaller, so that the power meter now fits even more frames! The battery life is also eight times longer than its predecessor. This makes it an ideal upgrade for your gravel bike!

Exact measurement
The Precision 3 Power meter gives a very precise reading with a deviation of only 1%. The force you apply causes the crank to bend and rotate in all three dimensions. To ensure that every force you exert on your pedal is measured in every dimension, 4iiii has developed the 3D power measurement system. This measurement system measures multi-dimensional load, so you can be confident that your unique pedal stroke will still be accurately measured regardless of your riding conditions.

Single-sided power meter
The 4iiii RX810 power meter measures power on the left crank and counts it twice to give you total power over both legs. For most riders without limitations, the power on the left and right leg is almost the same with equal efforts. Your cadence is also measured as standard.

Lightweight
Due to its very lightweight design, the sensor only adds 9 grams to a standard Shimano crank. This makes it the lightest power meter on the market!

Battery life
The 4iiii has no internal battery, but uses button cell batteries. The downside is that you do need to change them occasionally. Fortunately, the battery lasts for over 800 hours, which is a lot longer than most internal batteries in power meters and its predecessor. If the battery is below 15% you get a notification in the 4iiii Device Configuration. So you are always on time with your battery change.

Connectivity
The calibration is done via 4iiii Device Configuration. This app is available for Android and IOS. Through this app you can also see the status of the CR2032 button cell battery. This power meter sends both an ANT+ and a Bluetooth signal. This makes this power meter compatible with almost all bicycle computers. If you are not sure if your cycling computer or sports watch is compatible, you can check the user manual of your computer to see if it is compatible with ANT+ or Bluetooth and with power measurement.

Technology

• Connection: ANT+, Bluetooth
• Measurement deviation: ±1%
• Power supply: CR2032 (up to 800 hours)
• 3-year warranty
• Water resistance degree IPX7
• Active temperature compensation
• Power range: 0-4000W
• Cadence range: 30-150RPM

Compatibility

Caution
The part of the crank on which the power meter is mounted protrudes slightly from the original crank. This can cause problems with some bicycle frames. You can perform a test to determine whether your frame is compatible. To do this, you need to be able to move a AAA battery vertically between your crank arm and the chainstay. There is an image on the last product photo of this page to check this. Optionally, 4iiii website also has a handy document that you can print out and stick on your crank. Then you know exactly between which points the AAA battery must be able to pass. When there is enough space for the battery, you can assume that the 4iiii Powermeter is compatible with your frame!

Delivery includes

- 1x 4iiii Precision 3 RX810 GRX
- 1x CR2032 button cell battery

Assembly

In order to install this 4iiii power meter on your bike, you must first remove your current left crank arm. Mounting the 4iiii power meter is exactly the same as mounting a Shimano left crank arm.

1. Remove the pedal on the left-hand side.
2. Loosen the two crank bolts at the top of the crank arm and remove the safety pin from the slot.
3. Then remove the crank bolt with this crank tool.
4. Now the crank arm is loose and you can remove it from the axle. You may have to apply a lot of force here. The most important thing is that you do not damage the crank arm.
5. Next, install the powermeter crank arm by following the steps above in reverse order.
6. Then don't forget to fit your pedal to the new crank arm and you are ready to ride!


You can also have a look at this blogabout how to replace a crankset. Of course, you then only have to follow the steps concerning the left crank arm.

Frequently asked questions

How do I determine which crank length I need?
Crank length refers to the length of the crank arm and is measured from the centre of the bottom bracket to the centre of the pedal axle. Bicycles are usually delivered with the correct crank arm length for the corresponding body size. In most cases, the length is indicated on the inside of the crank arm. Otherwise, you can measure it yourself. It is important that the crank arm powermeter you purchase has the same length as your current crank arms.

What software and/or hardware is this power meter compatible with?
This power meter sends both an ANT+ and Bluetooth signal. Therefore this power meter is compatible with most current bike computers. However, not all computers are compatible with a power meter. For this, you have to consult the specifications of your bike computer.
The common models of Garmin and Wahoo are in any case almost all connectable. The Garmin Edge Explore cannot be paired with a power meter.

Compatible device (among others) are:
Garmin Edge 130, 520, 530, 820, 830, 1020 &1030
Wahoo ELEMNT and ELEMNT ROAM

If you don't have a cycling computer you can also use the 4iiii app to track your workout power data.

How do I calibrate this power meter?
Calibrating your power meter is very important to measure your power accurately. Make sure there is no weight on the pedals and that your right crank is up and your left crank is down (positioned vertically). Rotate the powermeter a few times so that it turns on. Then you can easily calibrate your powermeter via the 4iiii app. Another possibility is to calibrate your powermeter via your cycling computer. Most bike computers have this option, check the user manual of your bike computer to find out how to do this.