Power reading difference

Hey everyone,

I recently swapped my main road bike, which has a power meter, for another road bike without a power meter on my Elite Suito smart trainer. During a workout today (Makika, threshold 5x5’ with 5’ recovery), I struggled to hit my power target of 310 W in ERG mode. I ended up having to reduce the intensity by 10% just to complete the session, which seemed odd as I didn’t feel fatigued before starting.

From my understanding, the resistance level on the smart trainer should always be the same regardless of the bike being used, since it’s set by ERG mode. However, the power reading in this case comes from the trainer, not the bike’s power meter, and that could result in a slight difference, not a different target.

Although I’m aware that the bike doesn’t having a power meter could not affect the readings, right?
I’m wondering if there’s something else I’m missing? Has anyone else experienced this?
Anyway I think I have to accept I failed an easy workout :smiley:

Swapping from a bike with a power meter to one without would make a difference but only if you had linked your power meter to trainerroad as well as your smart trainer.

If you had previously linked the power meter trainroad would have taken power measurments from that and used power match to set the target.

You will now have switched to using the trainers power measurment for the first time.

If you contact support they will be able to tell you if there was a big difference between the power meter and smart trainer readings on your previous rides… assuming you had the power meter linked.

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What @kevistraining said

I had an Elite turbo and accidentally linked my pedals to the trainer once. It was only picking up my left pedal and so was putting out half the power - took me ages to workout how to unlink it. The online support and email support were really helpful though if you can’t figure it out.

Worth checking. My Elite turbo reads consistently 10watts higher than my pedals.

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Yes, in the previous rides I was doing workout with power meter and smarttrainer both linked via bluetooth to the trainer.
Anyway I’ll try to conctact support, thank you for the hint.

Today I used a bike without a powermeter, so only trainer linked via bluetooth and of course I got power from it. My concerning was not the reading actually but If this affect also the target power, since I had to dial off 10% intensity to complete a (supposed) easy workout.

Hey @fabio272 :slight_smile:

@kevistraining is right! I looked at your ride log data and you were using PowerMatch- readings were coming from your Power Pro power meter.

It’s very common for your power meter and trainer to differ in this way. In fact, I would say the majority of devices on the market will have some sort of differential when compared with any other device on the market and the majority of athletes experience this issue.

If you’re struggling to keep up with your workouts on your trainer, and the new setup with no power meter will be permanent, it could be worth bumping down your FTP by a few watts, or even taking a Ramp Test. :slightly_smiling_face:

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The Elite Suito IME is poor with its handling or ERG and I found it would constantly chip away at me without me realising until it was too late and I was sucked into the spiral of death. I do workouts in resistance mode for this reason.

Hi, thank you for the answer.
So, just to make it clear. Since I always used power match, the “resistance level” (so to speak) of the trainer corresponding to 310W on the power meter of the bike, is different from the resistance level corresponding to 310W on the power meter of the trainer, correct? And this last one can have a higher resistance at 310W?
It is possible that, that they differ as much as 10%?

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Not if they are both calibrated and working correctly and your drivetrain is running smoothly.

I disagree with kevistraining - I think power meters can differ from trainer by 10% or even more in some cases.

I recently went from using Kickr Core for power measurement to using a Favero Assioma UNO and after ramp test found that my pedal-based power was ~25% lower than the trainer was measuring.

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Indeed. Right, wrong or otherwise, power reporting between these devices seems to stray beyond the claimed accuracy in more than a few cases. Sometimes it is setup and/or user error, but we have seen several people apply extensive testing here to show deviation beyond the claimed low single-digit gaps.

It is definitely worth making sure all setup & calibration procedures have been done correctly for all devices in question. But even so, there may well be delta’s larger than the claimed tolerances that dictate some additional steps by the user to handle them for regular training use.


Oh I’m definitely not saying that they don’t differ by 10% or more… just that they shouldn’t if they are working correctly.

It seems like it’s the most likely cause of the issue here.

Perhaps. I wish my trainer and power meter matched more closely. But both were bought new, undamaged, and (I think) set up correctly. Nonetheless I have a significant difference in the power readings.

I use the power meter now after a ramp test established a new FTP. My ego is damaged because the new FTP is much lower than the old one, but other than that my training isn’t affected in any way and I’m hopeful that when I ride outdoors having consistent power readings will pay off.

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While it is good to do a ramp test (or whatever test you prefer) and establish a new FTP for your equipment change this is not a valid test to make claims about the difference in reading of equipment. Far too many factors, the main one being you not the hardware.

TR has the tools built in to compare. In devices you can see the power from your power meter and from your smart trainer. Not sure if it matters, but turn off power match just to be safe. Just pedal evenly and target an easy to calculate number like 100 watts on one of them (don’t bounce back and forth). Peek over at the other reading. You should be able to see a ballpark between the two pretty quickly. if you are Targeting 100 on the power meter and see 105 on the trainer look over and you’ll probably see you drifted to 103 on the power meter, don’t necessarily back off just see if they even out.

Very unlikely you will be seeing one read 80 and one read 100 or similar for a 25% difference.

It would actually be neat if there was a away to record this and do a comparison or if they had a % difference tool in devices.

The eyeballed comparison in TR Devices is a nice, quick start. But for anyone really wanting to understand the actual deltas between devices, a fuller test and data set with the tools covered in the FAQ are a better destination.

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There’s also the inherent difference in where the power is measured. Power meter pedals versus a wheel-on trainer for instance. One sees the strain directly at the pedals, the other ones sees the drive train losses, rolling resistance losses at the tire to drum etc.

Thanks I knew some tools existed (and was picturing Rays reviews/charts) didn’t realize they were in an FAQ here, very handy.

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