4iiii Precision power meter review

At just 9g the 4iiii Precision power meter is the lightest on the market

Cycling Weekly Verdict

Overall I have been very impressed with the 4iiii Precision power meter. Being left side only, it will never be as accurate as a dual-sided unit. However, by being single sided it is considerably cheaper. It is sufficiently accurate and consistent for most riders to gain useful information that will improve their training and therefore I can highly recommend it. The weight is also an attractive proposition, with the 4iiii being the lightest power meter on the market. So far it has worked very well, although having tested the unit for a month I will update the page if there are any long-term reliability issues.

Reasons to buy
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    Easy to fit

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    Ridiculously light

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    You can account for left/right imbalance

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    Scale factor adjustment

Reasons to avoid
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    Left side only not for everyone

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    We noticed some inaccuracy at high intensity

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You can trust Cycling Weekly. Our team of experts put in hard miles testing cycling tech and will always share honest, unbiased advice to help you choose. Find out more about how we test.

The 4iiii Precision power meter is a left-side-only, crankarm-based power meter. It can be purchased with a crankarm, or alternatively you can send your crankarm off to the company and it will fit the 4iiii Precision pod for you and post it back. The pod runs on a single CR2032 coin battery which, according to 4iiii, currently gives about 120 hours of battery life.

A Shimano 105 crank equipped with the unit costs £379, which is roughly in line with the price of a Stages power meter. If you send your own crank off to 4iiii, it will also charge you £379. In the meantime I have a 4iiii-equipped Dura-Ace 9000 crank to review (£549)

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Symon Lewis joined Cycling Weekly as an Editorial Assistant in 2010, he went on to become a Tech Writer in 2014 before being promoted to Tech Editor in 2015 before taking on a role managing Video and Tech in 2019. Lewis discovered cycling via Herne Hill Velodrome, where he was renowned for his prolific performances, and spent two years as a coach at the South London velodrome.