4iiii Ultegra R8100 Precision 3+ PRO Power Meter

From training in the rain to the most challenging races, the 4iiii Ultegra R8100 Precision 3+ PRO powermeter always gives you the data you need. With up to 550 hours of battery life, IPX7 certification, an automatic terrain selector and +/-1% accuracy, you'll gain insight into your performance and be able to optimise your workouts.

Double-sided or single-sided?
A double-sided power meter is a bit heavier than a single-sided power meter, but provides you with even more accurate and comprehensive data. The double-sided measurement, as in this 4iiii Ultegra R8100 Precision 3+ PRO, displays information from both legs, making it easy to spot left/right differences, for example. A single-sided powermeter simply doubles the single-sided measurement. With an accuracy of +/- 1%, this powermeter delivers highly accurate information about your pedal stroke.

"Apple Find My" & Automatic Terrain Selector
Thanks to 'Apple Find My' support, you can see the location of your powermeter with an Apple smartphone, iPad, Mac or Apple Watch. All you need to do is add the powermeter to the app. Even when the power meter is not in use, this way you can always see where your bike is. Furthermore, the new feature 'Automatic Terrain Selector' has been developed, which can detect different types of terrain. The powermeter then automatically switches between different methods to measure cadence, ensuring that your power output is accurately measured on any terrain!

Battery life
The 4iiii Precision 3+ PRO does not have an internal battery, but uses button cell batteries. The downside of this is that you do have to replace these from time to time. Fortunately, the battery lasts up to 550 hours, which is a lot longer than most internal batteries in powermeters and your favourite indoor trainers. Furthermore, the powermeter has an IPX7 waterproof rating. This assures you that the powermeter works well even in wet conditions.

Connectivity
This power meter transmits both an ANT+ and a Bluetooth signal. This makes this power meter compatible with almost all bike computers. If you're not sure if your bike computer or sports watch is compatible, you can check your computer's user manual to see if it is ANT+ or Bluetooth compatible and power meter compatible.

• Sensor weight: 29 grams
• Power range: 0 - 4000w
• Cadence range: 30 - 170RPM

• Suitable as a replacement for all Shimano Hollowtech II 12-speed Race cranksets.
• Connectivity: ANT+ and Bluetooth

How do I know if my bike is suitable for this powermeter?
First of all, it is important that you have a Shimano road bike crankset. If you don't have one, you will unfortunately not be able to use this powermeter. Other cranksets you cannot use are e.g. FSA, SRAM, Praxis and Hollowgram. You can also not use this powermeter on Shimano MTB cranksets due to a different design.

However, you can combine this powermeter with cranksets of an older generation. This can also safely be an older generation than the current groupsets. As long as the mounting method of the crank arm: the two nuts that keep the crank arm in place, is the same. You might then see an external difference.

Furthermore, it is important that you have enough space at the rear fork. If you do not have enough space here then this powermeter will not fit. Unfortunately, there is no way to make it fit. The best way is to check this with the 4iiii model.

How can I determine what 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. Bikes are basically delivered with the correct crank arm length for the corresponding body height. The length is indicated on the inside of your crank arm in most cases. If not, you can measure it yourself. It is important that the crank arm powermeter you buy is the same length as your current crank arms.

With which software and/or hardware is this power meter compatible?
This power meter transmits both an ANT+ and a Bluetooth signal. This makes this power meter compatible with most current bike computers. Only not all bike computers are suitable for use with a power meter. For this, you will have to consult the specifications of your bike computer. In any case, the common models from Garmin and Wahoo can almost all be connected. The Garmin Edge Explore cannot be paired with a power meter.

Should you not have a bike computer right now, you can also use the 4iiii app to keep track of your workout power data.

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