Have a core from April 2020 which is running latest firmware. Noticing that during sprints it’s reporting my power is 80-100 watts lower than what my pedals are showing. I have Assioma dual sided which are calibrated but also match my mates Powertaps dual pretty well
Normal riding is a lot better - around 5-10 watts lower sometimes, but I can take that given drivechain losses.
Have perform numerous spindowns using the terrible utility app on Android and also on Zwift, but still the same
Anyone else noticed this and have any tips for a fix or at least closer readings?
Yeah did see both this and gplamas videos but thats when the core would overshoot by 100w or more during sprints. My issue is the other way around and under reporting.
I got a core this last Nov. accuracy was good for many workouts usually within 1.5% of my SRM (which reads slightly under my powertap). The day I decided to join a tour de zwift ride the kickr started reading 10% low which made keeping up on the ride more difficult than it should have been. Not sure what caused the sudden change but did numerous spin downs without any improvement.
So far the only response I’ve gotten from the support ticket I opened was a canned email about powermeters in general not matching.
At this point I’m sceptical about the claimed accuracy. I suspect most people don’t compare power for every ride and wouldn’t necessarily notice a change. It would be good if there was some objective way to check the torque measurement used but I haven’t heard of one.
Have you tried the factory spin down? It’s like the regular spin down on EPO. I haven’t done one myself, but I did recently become aware of this. It does seem likely to be worth a shot first.
For my Core, I’m seeing the exact thing this firmware would fix. If I’m under maybe 17mph on Zwift at a power under 150w, it over-reports versus my Quarq. As soon as power and speed go up, it’s much more in line with reality.
Overall with my Core, I’m have the issue of it reading higher than my Quarq. Which is backwards. A trainer should read less than the meter upstream given the % drivetrain loss. Meaning, either the Quarq or the Core are off by more the % drivetrain loss!
I’ve done a spin down. May try the factory spin down thing.
I’m also going to fill a thin plastic bag with a known amount of water and read the torque in the Quarq app just to see what I get. I don’t think you can zero or tare off of that, but at least I would “know”.
thanks for the replies, interesting to see I’m not the only one.
few things; yup, tried a factory spin down once. Although there are articles suggesting you shouldn’t unless advised by Wahoo because ‘it can damage’ the trainer, but all fine afterwards, didn’t make a difference to be honest.
still seeing a constant 10-15 watts lower than pedals, way more more during a sprint.
It’s got me thinking if I should try calibrating when cold perhaps? Is it likely to boost the numbers up to match?
Last few spindowns have been after at least 30 mins of use when the unit is pretty warm. I know Wahoo suggests calibrating after 10 mins of use.
Also does it make any difference using the wahoo app for a spin down, the wahoo utility app (pretty terrible, but spindown works) and / or Zwift?
I know the power discrepancy I’m showing prob sounds petty to most, but it does make a difference, especially when racing on Zwift, which I love. If I’m going to use pedals for power, then I could have got away with buying a cheaper smart trainer
My brand new kickr core is spot on imo, roughly 2-4% lower than my garmin vector 2s pedals. You’d expect a pedal power meter to overread most during a max sprint I would of thought, as so much strain will be going through them. (I’d of thought, someone will soon tell me if I’m wrong). Also, dual record with your power meter, but use your turbo for your zwift power if racing, its viewed as better practice for a number of reasons, and having lower watts on zwift makes the extra few watts on the road seem all the more. I’ll attach my most recent dual recording data for comparison.
My Kick Core (2018 model) consistently reads 10W lower than my Vector3, while these in fact read 5, sometimes more watts lower than 2 other PMs I have tested against, which both have been consistent at least between each other.
My Kikr snap which is a wheel on trainer has always read 10-15% low compared to the Quarq power meters I have on my Tri bike and one of my road bikes. So the low reading issue may go beyond just the KICKR core line. Calibration never seems to change anything for me.
I mainly used the trainer power for zwift over Bluetooth while I simultaneously used my quarq over ant + with trainerroad. I don’t race on zwift so its not the biggest issue. It did annoy me though so I ended up using a second ant+ dongle so I could use my Quarqs for Trainerroad and Zwift at the same time.
Why not just use the “Control w/ANT+ Power Meter†function in the Wahoo app or the power matching function in Zwift? That way you are using the “true†power reading in your opinion to control your KICKR Core.
For my Core, I’m seeing the exact thing this firmware would fix. If I’m under maybe 17mph on Zwift at a power under 150w, it over-reports versus my Quarq. As soon as power and speed go up, it’s much more in line with reality.
Overall with my Core, I’m have the issue of it reading higher than my Quarq. Which is backwards. A trainer should read less than the meter upstream given the % drivetrain loss. Meaning, either the Quarq or the Core are off by more the % drivetrain loss!
I’ve done a spin down. May try the factory spin down thing.
I’m also going to fill a thin plastic bag with a known amount of water and read the torque in the Quarq app just to see what I get. I don’t think you can zero or tare off of that, but at least I would “know”.
I actually have the same issue. Comparing the results to a Sufferfest 4DP test, I think the Quarq was reporting 2-4% lower power than the Core. That was true at a bunch of power durations (5s, 1min, 5 min, 20 min). On a different bike with a Pioneer single side PM, the discrepancy was a bit larger, I think averaging 7%. I’m taking that as confirming that the Core is probably reading a bit high, rather than my Quarq reading low.
I think that one person on the Zwiftpower forum may have expressed the same issue. DC Rainmaker’s review of the Core seemed to say that the Core was reading high in sprints, but about the same in longer durations. If I read him correctly, anyway.
For my Core, I’m seeing the exact thing this firmware would fix. If I’m under maybe 17mph on Zwift at a power under 150w, it over-reports versus my Quarq. As soon as power and speed go up, it’s much more in line with reality.
Overall with my Core, I’m have the issue of it reading higher than my Quarq. Which is backwards. A trainer should read less than the meter upstream given the % drivetrain loss. Meaning, either the Quarq or the Core are off by more the % drivetrain loss!
I’ve done a spin down. May try the factory spin down thing.
I’m also going to fill a thin plastic bag with a known amount of water and read the torque in the Quarq app just to see what I get. I don’t think you can zero or tare off of that, but at least I would “know”.
I actually have the same issue. Comparing the results to a Sufferfest 4DP test, I think the Quarq was reporting 2-4% lower power than the Core. That was true at a bunch of power durations (5s, 1min, 5 min, 20 min). On a different bike with a Pioneer single side PM, the discrepancy was a bit larger, I think averaging 7%. I’m taking that as confirming that the Core is probably reading a bit high, rather than my Quarq reading low.
I think that one person on the Zwiftpower forum may have expressed the same issue. DC Rainmaker’s review of the Core seemed to say that the Core was reading high in sprints, but about the same in longer durations. If I read him correctly, anyway.
My best real world data point is full TT kit 40k at 25.6mph on 252w AP with time soft pedal stop sign right turns each lap. With the Quarq. Seems pretty legit.
Maybe I’ll take the power on Core as OK as an inflation for what extra I can do with outside airflow cooling.
My brand new kickr core is spot on imo, roughly 2-4% lower than my garmin vector 2s pedals. You’d expect a pedal power meter to overread most during a max sprint I would of thought, as so much strain will be going through them. (I’d of thought, someone will soon tell me if I’m wrong). Also, dual record with your power meter, but use your turbo for your zwift power if racing, its viewed as better practice for a number of reasons, and having lower watts on zwift makes the extra few watts on the road seem all the more. I’ll attach my most recent dual recording data for comparison.
Hi, is that comparison using Zwift power? I looked into that the other day, because it would be handy to produce a graph from my numbers, for free. Is there a way to convert my garmin tcx (from pedals) to.fit file if the distance is 0? Not using a speed meter for head unit, it just records power, HR and cadence.
thanks
Still curious whether calibrating at colder temp might up the watts to a more accurate level in line with my PM. Will try this soon
yeah, just go into analysis and pick the zwift activity and then in the comparison bit upload the fit file into it, I use strava files after my garmin has uploaded to it which I then delete off strava after there on zwiftpower.
joined TDZ ride this morning. Literally a 2 min warm up then into a calibration through Zwift when it was still cold. Don’t know if this is ‘bad’ for the unit but the number seemed a bit more inline with my PM. Will test again tomorrow.
joined TDZ ride this morning. Literally a 2 min warm up then into a calibration through Zwift when it was still cold. Don’t know if this is ‘bad’ for the unit but the number seemed a bit more inline with my PM. Will test again tomorrow.
Do you happen to know if smart trainers like the Core/Kickr (direct drive) should read lower or higher on a cold spindown?
I’ve always done a spindown right when jumping on the thing as Zwift recognizes the devices on that screen.
joined TDZ ride this morning. Literally a 2 min warm up then into a calibration through Zwift when it was still cold. Don’t know if this is ‘bad’ for the unit but the number seemed a bit more inline with my PM. Will test again tomorrow.
Do you happen to know if smart trainers like the Core/Kickr (direct drive) should read lower or higher on a cold spindown?
I’ve always done a spindown right when jumping on the thing as Zwift recognizes the devices on that screen.
That’s what I’m trying to find out. First time calibrating when colder and overall watts seemed much closer to that of my pedals
