Just Got a 4iiii Power Meter. Do I need my Cadence Sensor?
 

Hi everyone. New here. Psyched to join and spread knowledge in cycling and learn along the way. I just bought a 4iiii Ultegra power meter for my bike. I'm wondering if I need the cadence sensor attached from my old arm on the new arm as I heard that they also have a cadence sensor build in. Just wanted to clarify and ask if anyone can help with this.

No. Power meter will provide cadence. You can search for a cadence sensor on a head-unit and the same ANT ID will show up for both power and cadence.

To determine power at the crank arm, it needs to know how hard you're pressing and how fast you're turning the pedals over. And PMs all promise somewhere in the ballpark of 2% maximum error, which they can't achieve by relying on an external cadence sensor, so they have their own.

Not all PMs have a cadence sensor because if you measure at the hub, you don't need cadence. But yours does.

Welcome to the forums! I have a 4iiii PM as well. Great device. Can't speak highly enough about the unit (even if the L/R issue has yet to be sorted via a software update). I had the same question as you when I installed my PM. The good news? No need for a cadence sensor. The PM will handle that for you. As @saverin mentioned, you just need to bring the field up on your bike computer. Cheers.

Cadence to Garmin, how?
 

Hi,

I get the power to my Garmin but I’m not able to get the cadence. The ANT ID shows up on power but not cadence.

Would love to solve this so that I can remove my Garmin cadence meter.

Thanks

Have you tried riding yet? I have a garmin I use with an SRM and I think once power was connected, the unit automatically found the cadence data.

Hi,

Thanks for your response.

Yes, I have and it didn’t show up on the head unit but did appear when I transferred to Garmin Connect and Strava.

Did you add the cadence field to your screen?

Yes, and there is no problem getting it on the head unit when the Garmin cadence meter is paired.

PowerTap hubs give you cadence.

Un-pair/re-pair often helps. Remove & un-pair the Garmin cadence sensor as maybe it is getting in the way?

Garmin cadence meter is unpaired. I have tried it with the 4iiii as well but will give it another try.

Thanks

Did a full reset of the Garmin (which obviously unpaired everything) and it still did not pick up the cadence meter when I searched for it. However, it now relays the cadence info to the head unit. 🤷‍♂️

I guess all info is relayed through the power meter connection/pairing and all it took was a full reset of the Garmin for it to work somehow.

The old “Have you tried Alt-Ctrl-Delete?”.

Thanks for all answers.

Any time Garmin's give you a strange or what you think is strange issue, then do a reset. I've known some people with other types of Garmin devices that do a reset every time they do an update. Knock wood, I haven't had to but just a few times.

Powertaps measure cadence, too.

They don't connect as separate devices. At least, mine doesn't (crankset), and neither does yours, it seems.

Mine doesn’t either.