18w drop in ftp..😫😫

I just did a ramp test after ssb2 and have had an 18w drop in ftp but I think I may know why and wanted to see what you guys thought and how I should move forward. First thing is that on week three of ssb2 I switched from the kinetic inride to a 4iiii power meter. It seemed as though the power was pretty similar and I was able to complete my workouts until jepson and palisade. Not complete fails but I did have to take breaks/reduce power in the final intervals. The same thing happened on mills and my thought was that I was just getting tired late in the plan. So then rest week was fine, hr seemed lower for these workouts and I was expecting to see a jump in ftp as a result. Didn’t happen. I thought something might be up so I recalibrated my power meter and after recalibration I was putting out 10w more at the same cadence. Is it possible that it Miscalibrated before I started the workout? What should I do from here? Should I retest Thursday and see what happens or should I keep my current ftp and see how it goes. I did tunnaboro-5 after the ramp test and hr seemed lower than normal after a ramp test. I am kind of confused on what I should do now? Everything seemed to be pointing to a bump in ftp but it just didn’t happen. Thoughts?

Keep a consistent power meter. Is the 4iiii a single sided? Also the Kinetic I believe is estimated power if I remember correct. Its easy to get hung up on what your ftp number is but you need to realize its a training metric (I need to remind myself of that quite a bit). Start using this new PM to set zones and go from there.

It is often recommended to retest any time you change your primary power measuring device, right away. This includes any change from one power meter to another. It especially applies when switching from something like the InRide (which is basically Virtual Power) to a real power meter. As much as we’d like, we can not freely assume these meters will match, because most often they do not.

  • Swapping devices means you are likely to get different training that is too easy or too hard.

  • Also, since you effectively change “tape measures” you can’t really say that you lost or gained watts. You did a test with one tool, did some training, switched measuring tools, did more training, and did a test. You should not compare the old and new test.

Just ignore the old info. Use the current power meter data and move forward in your training. Keep everything as consistent as possible, and you can compare data over time. Change any variable, and that becomes more tricky and in some cases (like this one) totally irrelevant.

As far as calibration, there’s no way to know. Make sure you follow the manufacture process and recommended frequency. That is the best you can do.


The inRide calculation on my Kinetic trainer is very different than my actual power meter, I confirmed this again this morning just on curiosity. For example I was warming up at around 160w according to my PM, and the inRide said 90w. inRide is probably better than nothing but it’s really just an estimate.

Like Chad said, retest with your new PM and use that consistently.

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I think just for my sanity I am going to have to retest. I am getting hung up on the 10w difference when I recalibrated and need to remove all doubts that I might have. I just can’t let it go for some reason.

Are you going to retest using the kinetic power then?

No I will be using the 4iii.

Great reply Chad.

I was just wondering if there was a FAQ list on this Forum? If only to stop you from having reply to questions like this so frequently…

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This basic power meter change issue is one that I plan to add, and have addressed in a couple of different posts over the years. I need to pull the good from those different ones into a single post.

When possible, I search and refer to existing posts from me and others to address various problems and questions that we see regularly.

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I’m asking b/c for me it would be much more interesting to know if I improved to SSB2 (comparing With the same setup). The calibration issue i would figure out as I move fwd.

I didn’t want my question about FAQ to become a FAQ :wink:

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I might run the kinetic on a separate app and just get a rough estimate from that, but I haven’t decided yet. I’m planning on retesting tonight so I will update today or tomorrow.

I have watched a few videos on calibrating s power meter to make sure that I have been doing it right and a couple have said that I should get a number telling me if it’s calibrated correctly or not. I have not been getting any info after I calibrate so am I missing something? All firmware is up to date.

That can depend on the exact device and/or app you are using to do the Zero Offset. Some return numbers, while others do not.

What are you using for you Calibration / Zero Offset?

I used the 4iiii app and trainerroad and got nothing on both.

OK, that seems right AFAIK.

Some head units will show a value (Garmin usually). It really isn’t “needed” to see the value. You can see whatever crazy number that sometimes shows, and keep mental track of it. But other than seeing that it is generally in a given range (per the PM maker), there is not much use to seeing or knowing it.

As long as you get a completed C-ZO, you should be good to go.

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Alright, so I did another ramp test last night and gained 1w while using the 4iiii power meter, so that answers the my question about calibration being off on my previous test. I also ran the inride on a separate app the background. The only thing I could measure between the two was average power for the work out and the inride came in 16w higher. My question now is do I offset my power meter to match what the inride says just to be able to compare seasons or just leave it alone? I am going to feel like I am lying to myself if I do, but I would also like to know if I am getting any prs. Ideally there would be a way to offset my numbers from the inride but I am not sure this is possible. If there’s a way I would love to know how.

I would not offset an accurate tool (the power meter) to match an inaccurate tool (inride). That is backwards in my eyes and will mess you up for outside riding in the future. Let the old incorrect data be what it was and move forward with the new tool and it’s more accurate info.

Do make a new season, that is timed to the implementation of your new power meter. Pay attention to your new PR’s in this new season and ignore the old stuff from the inride.

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I compared power using dc rainmaker analyser 4iiii VS Neo and found 4iiii to be consistently higher by about 2-4%. Also anecdotally found 4iiii to occasionally give higher than expected power pre calibration which I unfortunately couldn’t attribute to being stronger. Works both ways. Testing is also a one off and depends on plenty other factors. Wouldn’t worry. Keep training hard, calibrating and resting.

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