Drive side power meter query

Can you use the 4iii drive side power metre without the left?

Basically, I have a TT bike with shorter cranks.

I’m looking to purchase the full 4iii power metre set, put the drive side on the TT bike, and the left crank power on the road bike, and then swap the old TT drive side crankset onto the road bike.

So the result would be both bikes have the same crankset length, and both bikes now have power data, one reading from the left and one from the right.

I can’t find information online about using just the 4iii right side power without the left.

Any help appreciated


Im pretty sure it needs both to work. Also, if you are measuring only the left power on one bike and right power on another bike, would there not be noticeable power differences?

Can I suggest to use a pedal based power meter so that you can easily swap to and fro from both bikes?

or maybe left sided crank from the same manufacturer on both bikes to keep both data as consistent as possible.

Ah that would be a shame if the right side doesn’t work on its own like the left can.

If I got left side for both I would still need to buy a shorter drive side crankset for my road bike, and then also have a left side crank spare / wasted once removed from the TT bike. My suggested option would be the cheapest if it worked.

In terms of data, I’m pretty even with both legs, and the left side has an offset option if there is a discrepancy

okay, if your legs are even, the option to buy one power meter and split it into two bikes is not available.

most dual sided power meters need to connect to each other before riding and one side becomes the master. unless I am wrong.

maybe you can share on whats your budget for the power meter as well as your options?

Um, I’m not sure about that. If one sides battery goes flat it would be a pretty bad design if the ‘good’ side couldn’t go on measuring. I think you just lose power balance and get readings from the ‘good’ side (drive or non-drive) side.

So do we think the right side on it owns can work independently, like the left, and basically just double the reading to measure total power output?

You can run either side as an independent power meter. You then pair them to get dual readings. If one failed you might have to unlink the working one in the app so it stopped searching for its twin, but essentially either side can work alone. At least that’s how i read if from the information on their site and the [user manual].(

Also, they sell drive side only PMs without a requirement to buy the non-drive side and they wouldn’t do that if it needed both.

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Oh fantastic, so i can just not link them and they should operate independently. The manual makes this quite clear, apologies for my laziness here… i searched all the forums and didnt think of just downloading their manual :sweat_smile:

Seems like a half-baked plan.

(That’s a joke!)

I just want to give this a +1. I own a 4iii dual system and they can be independent or paired.