4iiii Precision 3 Power Meter Shimano 105 R7000

The 4iiii Precision 3 Power Meter is accurate and easy to live with. A longer battery life than previous models means fewer battery swaps, and the consistent data makes it easy to train with on a daily basis. For UK users this is also the fastest way to get your existing crank converted to power measuring. There's a lot to love.

While a lot is made of a power meter's accuracy compared with other power meters, for many riders who can only afford and therefore just use one power meter, the main thing is getting data that yes, is accurate, but getting it consistently, day after day, with no dropouts or weird spikes.

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In terms of this consistency, the 4iiii Precision 3 has been perfect, and after a firmware update to this pre-production sample that I've been testing for a few months, things have been plain sailing. The device wakes up and connects quickly to my bike computer, the data delivered has been reliable, and there have been no bugs to cause frustration.

Compared with the Precision 2, 4iiii has increased the length of the power meter's plastic body, but the height has been reduced to just 5.5mm. Clearance has never been an issue with my frames, but I know that some Canyon frames, amongst others, have been unable to accept a 4iiii Precision power meter. The slight reduction in size could help here.

The other big change is that the Precision 3 comes with a claimed 800-hour battery life. That could mean a vast reduction in the number of times you need to change the battery; having only ridden for 70 hours so far in 2022 (not all on the 4iiii), I'm nowhere near needing to change it. Even if you were training like a pro, logging 30-hour endurance weeks, you'd still be fine for months.

I can't verify those battery life claims, and it will likely depend a fair bit on your riding conditions as batteries don't like cold weather, so I can't give an indication of how accurate this claim is.

Accuracy

I got the Precision 3 well ahead of the unit's launch and that meant two things. Firstly, I wasn't able to get a Shimano Ultegra crank as there was no 170mm size. Instead, I was sent the 105 model, althoug that really doesn't bother me.

Secondly, I was using the Precision 3 before all of the creases had been ironed out. My first few weeks on this power meter presented a few issues. In terms of accuracy, this meant that I was seeing numbers that I've always wanted to see – unfortunately, my max sprint power isn't 1,309 watts, and in late December there is no way that I can put out 323W for 11mins 20secs, especially having just recovered from Covid and spent the previous week doing Christmas-level drinking and eating. For context, the sprint power was about 200W high and the longer effort would typically be around 300W. Those are significant differences and a quick ride on the indoor trainer confirmed that the crank was reading high.

Thankfully, after a few messages to 4iiii and a little update on the app, the numbers returned to their depressingly normal-looking values. Covid doesn't give you superpowers, as it happens.

Since then, the numbers have been reliable and consistent, which is just what is needed for regular training. I haven't seen any dropouts, which is very nice when you're riding on Zwift as I don't want to be dropping back through the group for any other reason than my shoddy fitness.

Installation

Installation is super simple, and if you're running a few bikes with Shimano cranks then this is a pretty easy one for swapping between them. Yes, it's still not as simple as something like the Garmin Rally pedals, but it certainly isn't the hardest job.

The Precision 3 is rated as IPX7 waterproof and really, this just means you'll be safe to wash your bike and ride in the rain. I've had zero water ingress issues with numerous older Precision power meters, and with the battery door remaining the same I don't see there being any problems here.

The 4iiii app continues to be simple and easy to use, and since the firmware update I did after the week of weird data, there have been no updates to do.

Value and conclusion

Rivals come from the likes of InPeak's 105 crank at £290 and Stages with the G3 105 R7000 crank coming in at £325. All three are brilliant ways of getting power on your bike for a relatively palatable price, but 4iiii does have a slight advantage for UK customers. Its factory installation process, which takes your existing left crank and makes it a power meter, is done in the UK. The cost is the same as the Stages factory install at £299.99, but 4iiii will do the installation in the UK, whereas a Stages crank has to go back to the main factory in the US. The difference is roughly a one-week turnaround compared with four to six weeks without your crank.

> 12 reasons why you should buy, and use, a power meter

All in, the 4iiii Precision 3 brings an impressive boost to battery life in a package that is a little bit thinner and just as good for the everyday cyclist as the previous model. The data is accurate and the consistency of the unit makes it easy to live with. You can have your existing crank converted for a very reasonable price in a short space of time.

Verdict

Still accurate and still a brilliant way to add power measuring to your bike for a sensible amount of money