Favero Assioma - suddenly become erratic after 18m trouble free use

Hi there, just trying to find out whether many others are having issues with their Assioma Duo. Been using mine out on the road now for around 18m and have enjoyed trouble free operation until the last week or so. I am now finding that I am having spells of under-reading and spells of over-reading - seemingly accompanied by big swings in L/R balance, though with no clear pattern.

For instance I calibrated before a ride this morning and found that overall average power for the ride was around 15-20% less than I would have expected and with an overall average L/R balance of 45/55 (I am used to seeing anything from 50/50 to 47/53 but not 45/55). This is actually an improvement on my previous two rides which had much bigger discrepancies. I then recalibrated after a coffee stop before a 20min ride home which finished with an average L/R balance now skewed heavily to the left at 57/43.

I have seen other erratic behaviour in my previous two rides - on the first problem ride I had half the ride with a power reading an estimated 20% under perceived effort and then following a mid ride re-calibration finished the ride with power reading an estimated 20+% over (for which TR awarded me some “best all time” trophies which was nice) and with average L/R balance skewed as much as 60/40 for significant spells.

During the last week (and after the first problem ride) I have updated to both the current Assioma firmware and the new Edge 530 firmware, but this did not fix the problem. Also I have always followed the same routine of calibrating (carefully) before each ride - and have swapped the pedals between bikes a number of times without problems (and in fact did so this week between two or the problem rides).

I have seen on a thread on dcrainmaker’s site that he has relatively recently started having issues with two different pairs of Assiomas which he has currently shelved until he gets chance to investigate. I might have this wrong but I gather one pair is a pair he has used previously without issue, and the other pair is a new pair. Could be entirely unrelated coincidence of course.

I have submitted a request to Favero technical help a couple of days ago and am currently waiting to hear back from them but thought I would see how others are getting on in the meantime.



I’ve had zero issues after 8 months of solid use… You might though want to try setting as UNO within the Favero App, test and then re-enable as DUO?



1 Like

Interesting idea thanks - certainly worth trying.

Yeah, one pair is a pair I bought at launch (so two years old), and another pair is one I also bought recently - sometime this summer. It’s only got a few dozen rides on it I think. Totally different batches, but both on the shelf now.

(Well, technically I took one pair off the shelf to take photos for my Smart Bike Roundup as I was running out of pedals for the picture. But not using it for testing, I’ve reverted back to a P1 for the bike it was on, and another set of Vector 3 to replace the other set. Sigh.)

1 Like

Since Favero allows calibrating with a static weight, you can at least check if the pedals give you similar results there. I think the way Favero does the weight check is great, and is very useful even if you don’t have a calibrated weight. I’ve been digging into Kickr power issues, so was also checking my pedals to try to make sure they were giving the right numbers.
What you can do is this:

  • Get a weight of about 10kg - that’s the minimum that Favero supports. It doesn’t matter exactly what it weighs, since you will just be comparing left/right differences.
  • Hang the weight from each pedal as the app instructs you to. You will get what the pedal is measuring the weight to be. Write this down for each pedal. Cancel out of the process of adjusting the scaling factor since you don’t have a calibrated weight. As I understand the process, all this calibration will do even if you accept it is to change the scale factor, which is user editable anyway. They really did this right. I think the scale factor and weight calibration are two really useful features that the Assiomas have over their competitors. I think all PMs and smart trainers should have editable scale factors.

With this procedure you can at least verify that both your pedals still have the same ‘slope’. If this shows a big difference between the pedals, then you have identified an issue. It sounds like you have intermittent problems, this may not catch it at all, or may require many tests to catch the issue.

My pedals came out quite close and repeatable:
Right assioma measured: 8.88, 8.89
Left assioma measured: 8.80, 8.79
within 1% of each other, and very repeatable.

I will definitely give this some consideration - it had crossed my mind but I was concerned about muddying the waters and had thought to leave to one side until I had some input from Favero. However, if I read your post right it looks like I can approach this simply as a measurement without having to commit to making any changes which is cool. Though as you also note since my issues don’t seem to be consistent it might not throw much light on the matter.

Yup, you can just do the measurement and not make any changes, which is really nice.

This test may not find anything, but if it does identify a big difference between the pedals then it does give a good indication of what is wrong (ie the force measurement is wrong.)

1 Like

That’s interesting. I’ve had some trouble with mine, though I’m not sure it’s the same. After about a year of use I’ve been having dropout spells on mine for ten to twenty seconds at a time, sometimes less. I use a Garmin 520 head unit. I’m not sure it ever wildly over reads, I’ve never seen any sudden surprise prs, but I’ll definitely watch lap power decrease suddenly as I’m maintaining or increasing effort, then switch to current power and see it as zero while I’m climbing or something, then suddenly jump back up.


Yep had the similar issue just before the warranty ran out. The charge also failed in the end. Favero were pretty quick to respond. Said they had the data from the unit (more big brother) and it was defective. Sent photos to show there were no pedal strikes. They sent me a replacement spindle. Since these things are potted in resin they can’t be serviced. So it is probably a new spindle.

1 Like

I have this exact thing happening with my Duo’s. Where you able to resolve the problem? I did open a ticket with Favero but so far no luck with finding a solution.

I get the drop outs as well, as does my friend who has them (Bolt and Garmin, respectively).

Yes I did. After opening a ticket Favero asked me to do some testing - they then remotely ran some diagnostics which are reported when pedals are connected to the app. I also sent them some Garmin files from rides with clearly erratic data. They determined there was some odd behaviour from both sensors and asked me to send the pedals back to them for testing - which I did. After tests in their lab they replaced both sensors under warranty. They also replaced the left pedal body under warranty - I’m not sure what was wrong with that but as a side note I had always had to use a washer on the left pedal to clear the crank (various crank sets) but not the right, so perhaps this body was always defective. I paid to have the right body replaced to match - I had wanted the newer bodies (black springs/lighter tension) anyway so was happy to do this.

Got the pedals back last week and used them for the first time last weekend and they were fine.

Stil no idea why they developed a problem but Favero’s customer care was first rate and I have two virtually new pedals (I assume I still have the original spindles).


Just for clarity - I didn’t get any drop outs I just started to get bizarre readings such as reading clearly too low for one ride then way too high for the next, with behaviour sometimes changing mid ride after a re-calibration. I also go some exaggerated L/R balances and some unrealistically high torque effectiveness readings. All very odd with no clear pattern - at least not clear to me.

1 Like

Thanks for the feedback, I did disconnect and reconnect the right pedal and that solved the issue, at least for last nights ride. Fingers crossed.

Similar problem here… after more than one yea without any issues, suddenly my favero DUOs are no longer accurate… I’ve tested them both with a NEO2 and Kickr18 and is reading higher than the trainer. I validated the findings by mounting Vector 3 which were spot on with the Kickr18

No idea why the Assioma DUO would suddenly develop this problem, but can confirm it’s real. Now that I know others are having the same problem, I’ll reach out to support to check what they say.

The difference is not much (about 6 watt), but it is noticeable after more than one year where they were within 1-2 watt of the NEO2 on every single ride.

Check out your left/right balance split as recorded, and see if it’s shifted a bunch.

Though I would say that realistically/technically 1-2w of a NEO would probably actually be inaccurate (at say, 250w). Whereas 6w would probably be closer to accurate. Or somewhere in between, due to drivetrain losses. Pedals should always be higher than trainers. Always. Typical drivetrain loss is usually 1-3%.


Agreed, I always expect higher power at pedals than trainer (or powertap hub in my outdoor rides). What concerns me the most is the drift in the performance from before. Whereas the difference has always been < 3w and very consistent, now, in some rides is as high as 10w, mostly around 6-8 watts above the trainer, but with variation from ride to ride, and also within one ride… in some intervals it can be as high as 12-14 watts, then others it is within 3-4 watts. The inconsistency is probably what’s most concerning.
The L-R variance has remained consistent at about 55-45.


I should just mention that in my case (original poster) when my particular problem arose I didn’t need to pit them against a trainer to see there was an issue - the numbers were clearly multiple tens of watts out and even several hundred watts out on one occasion. I wouldn’t have noticed otherwise.

I have also got this issue which has appeared in the last month and seems to be getting worse. Noticed at first that I had 60/40 L/R balance which was odd as my BePro and previous readings all showed 52/48 pretty much consistently. I then started to notice high power readings. Each calibration seems to reset it for a while and then it drifts again getting out by 15-20w (possibly - sometimes much higher like 100w). I have even ridden right leg only drills and still had a left power reading of 20w!
Any other ideas on how to sort - are these errors connected with their software release of 4.25?
I have raised a ticket with them.


Both of my pedals have been replaced now for this issue - the right one after 6 months and the left after 18.

Support were excellent though - I’m sure they will get you up and running again.