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What is the difference between the PRECISION and the PRECISION PRO?

The PRECISION is a left-only crank arm-based power meter and replaces your current left side crank arm. The power meter takes the power that is generated by your left leg and doubles it in order to determine your total power. The PRECISION PRO takes the original single-sided PRECISION to the next level with dual-sided power. The PRECISION PRO locates a power sensor on both the left crank arm as well as the chainring, allowing you to measure both left and right leg power independently.

Can I use the PRECISION on both my road and mountain bikes?

Yes. The 4iiii PRECISION is compatible with both road and mountain bikes that use Shimano cranks.

How do I know if the PRECISION is compatible with my road bike?

The PRECISION is compatible with the following Shimano road cranks:

  • 105 5700/5800
  • Ultegra 6600/6700/6800
  • DURA-ACE 7900/9000

How do I know if the PRECISION is compatible with my MTB bike?

The PRECISION is compatible with the following Shimano MTB cranks:

  • XT M8000
  • XTR M9000

Is my bike frame compatible with the PRECISION?

PRECISION needs 10 mm of clearance between the crank arm and the nearest bike component. This isn’t an issue for most customers, but some frames do have tight clearance so pay particular attention when marking the installation location. Customers with bikes that have bottom-bracket mounted brakes might also have clearance issues. Please see this frame compatibility guide for more information.

How much does the PRECISION weigh?

The PRECISION pods ads a mere 9 grams to your crank arm. This makes it the lightest power meter you can buy.

What conditions can I use the PRECISION in?

The PRECISION is waterproof and dustproof, and can be used in temperatures between -20C and 40C. PRECISION power meters can be stored at temperatures of up to 85C.

Can I move my PRECISION from bike to bike?

Absolutely. A crank arm with PRECISION installed can be moved to a different bike, assuming that it has a compatible crank installed, and crank arms of the same length.

How durable is the PRECISION?

The PRECISION pod is placed on the crank arm so that it is situated in a protected area. We have not encountered nor do no we anticipate any issues with durability.

How does the PRECISION communicate with my bicycle computer or head unit?

The PRECISION transmits data via both the ANT+ and Bluetooth SMART wireless protocols. This means it is compatible with any bicycle computer, smart phone or tablet.

How to I update the firmware on my power meter?

Please see here for step by step instructions.

Does the PRECISION come with a warranty?

Yes. The PRECISION comes with a one year warranty which covers the product from defects in material and workmanship.



How hard is the PRECISION to install?

The PRECISION is one of easier power meters to install. You simply remove your current left side crank arm using a 5 mm Allen wrench and a Shimano preload cap tool and then install the 4iiii power meter in its place. Installation takes about 5-10 minutes.



What type of batteries does the PRECISION use?

The PRECISION uses one CR2032 battery. We like CR2032 batteries as they are cheap and very easy to find. Note that batteries are provided with the power meter.

How long do the batteries last? Are they difficult to change?

Battery life is right around the 100-hour mark. When you have 15% battery power remaining, you will receive a low-battery alert on your head unit. This is a nice touch and serves as a reminder to replace your battery soon. The battery is changed by hand in a matter of seconds – no tools necessary.



Do I need to calibrate (zero-offset) the PRECISION every ride?

The PRECISION should be calibrated before ever ride – which is standard procedure for power meters. Calibration only takes 30 seconds and is performed using your bicycle computer.



I am having trouble updating the firmware on my PRECISION. Any ideas?

Please make sure you have the latest version of the app. For Android devices, it’s version 1.8.0. For iOS devices, it’s version 1.26.0. In addition, here are a few tips to keep in mind when updating your firmware:

  • The closer you are to your power meter, the better (don’t try to update from another room)
  • If you receive a text, email or call on your phone while updating, it can interfere with the update
  • Don’t exit the app until the update is complete

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