Pre-May 2023 4iiii Power Meters Have a Plastic Problem

A friend recently noticed that the plastic housing around the power meter pod on their crank was cracking. As the PM was still under warranty they reached out to 4iiii for assistance and found out that this is a larger issue with the plastic formulation used in pre-May 2023 power meters. If you have one of these, it would be a good idea to be extra careful. Or maybe the opposite :).

Micheal (4iiii)
Mar 26, 2024, 11:02 MDT
Hello <name removed>,

Thanks for reaching out.  I’m sorry to hear of the issues you’re having with the drive side plastics.

We have now changed the design of the plastic powermeter housing for both the NDS and DS of the PRECISION PRO powermeter to alleviate the issue of plastics that were prematurely cracking.

Below is a summary of the issue we have been seeing with mainly our DS powermeter:

In recent years, bicycle lubricants have trended away from oil based lubricants to wax based lubricants. Cleaner/degreaser companies have had to adapt to develop products that remove wax based chemicals from drivetrains. Wax and polycarbonates (the plastics we use for our powermeters) have similar chemical properties, so upon contact, certain cleaners/degreasers will also degrade plastics on your bike causing them to become brittle and crack.

How we recommend you maintain your power meter while cleaning your bike:

We recommend covering your power meter to avoid direct contact with any cleaner/degreaser. If you get cleaner/degreaser on your power meter, make sure to rinse it off  immediately. We also recommend taking the battery cover off when dry and wiping down the gasket area with a dry paper towel to ensure that no cleaner/degreaser has gotten in between the gasket and fasteners. To learn more about how to care for your power meter, please click here.

As of May 2023, all of our Factory Installed and warranty repaired PRECISION PRO powermeters have been with the new plastic design, that is more resistive to negative chemical interactions with common bike degreasers, and should significantly extend the lifetime of the plastic housing.

Unfortunately, as your powermeter is already cracked, it will need to be sent back to our factory in Canada to have the powermeter repaired.   Please complete the Return Merchandise Authorization (RMA) form attached to this link:

<link removed>

Once you receive the RMA number, please ship us your crank arm.  As per our warranty policy, we ask that you pay and arrange shipment to 4iiii.  We will then cover the return shipping cost and all import tax charges on its way back to you. You will also receive information on how to track your repair. It should take roughly 10-14 business days and 3-4 business days for shipping it back to you.

We recommend sending it via courier with a tracking number. Be sure to include your return address and copy of the bill of sale. Once the repair is complete, we will ship it back to you with a tracking number.


4iiii Customer Experience Specialist

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