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Garmin Forerunner 945 and Bicycling FTP calculation

Hello all,

When does the Garmin Forerunner 945 recalculate/update the Bicycling FTP when you do NOT have a FTP device?

Garmin Connect shows me 255 W at 20.02.2021 - but why on this day? There were lots of earlier bicycling tours and partially even longer ones, I started using it around one year earlier (February 2020).

What needs to be done to update the value again? I'm sometimes going with and without the chest strap although it doesn't really make sense for bicycling since it doesn't give you any further data compared to just wearing the watch.'

Due to weight loss and fitness programs, I'm no longer the person I've been one year ago, so I think my performance would be much better right now...

Thanks :)

BR
Frank

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0 e7andy over 2 years ago

You need a power meter on your bike.

"FTP stands for Functional Threshold Power and is effectively a measure of the power you can hold for an hour, measured in watts."

You likely also need to enter your current weight.

0 FrankBMUC over 2 years ago in reply to e7andy

Thanks, I know that but that wasn't my question. I don't have a power meter.

My question was why did the watch calculate 255 W exactly on that day. My weight was/is up to date.

Obviously it can update the FTP value even without a power meter...

0 e7andy over 2 years ago in reply to FrankBMUC

What exactly did you do that day? 20.02.2021

0 FrankBMUC over 2 years ago in reply to e7andy

Relaxed bicycling session of around 20 kilometres, far away from my lactate threshold or anything...it's no longer in Garmin Connect but Strava since I'm synchronizing with Strava. Yes, that's the question, why did it calculate 255 W on that day...

0 e7andy over 2 years ago in reply to FrankBMUC

Why no longer in Garmin Connect? You can see your data for that day with this link: https://connect.garmin.com/modern/daily-summary/2021-02-20

When I look at my historic FTP values I see data points for activities where I didn't use a power meter, but those values never changes. They are staying the same.

Have you manually set your FTP to a value?

0 FrankBMUC over 2 years ago in reply to e7andy

Yes, I meant in the app, I can see it on the website. 11 and 12 km bicycling with a maximum heart rate of 113, so absolutely relaxed.

And no, I didn't set any value manually as I don't have/know any FTP value for myself. I've never done any bicycling power test or something like that.

0 e7andy over 2 years ago in reply to FrankBMUC

It could be like the Cross Country Skiing FTP. I guess we all got a value without doing any actual cross country skiing.

To get a new FTP value you need a power meter.

0 tmk2 over 2 years ago in reply to e7andy

I have the same issue. It's definitely not a XC skiing FTP, as it shows in cycling ftp in garmin connect. The last update of my cycling ftp is from July 24. On that day I did not do any cycling acitivities, just a short run. I never-ever used a bike power meter. I do cycle occasionally, but none of my rides contains any power data. And yet every now and then a cycling ftp appears in garmin connect. The creepy thing is that the ftp value is about right, i.e. I don't know my real ftp, but being a fairly decent long distance runner (performance-wise), I am a fairly poor cyclist, and the cycling ftp that I see seems to reflect this.

0 FrankBMUC over 2 years ago in reply to tmk2

Exactly my thoughts. My value appears to be realistic too. But I wonder when and how it's being updated. It didn't update after any bicycling tour since.

A real power meter is way too expensive anyway unless you're a professional and taking part in races and stuff.

0 e7andy over 2 years ago in reply to tmk2

I meant that it is like the Cross Country Skiing FTP. A value that is set for some reason without we doing the needed activity.