Power match - Adjusting Kickr power when NOT using Vector 3 pedals

Hi, The problem I have is that my Kickr Core appears to be reading around 10-20W less than my Garmin vector 3 pedals. This is across the power range (and between bikes). Most of the time I solve this by using power match and letting the Vector 3 be the guide by which Trainer Road adjusts the power. The power match is set to “Automatic”. Reading the garmin pedals on my garmin device and the kickr power on a elemnt, there is this clear difference. TR is using the Vector 3 readings in the session. If I use the Kickr Core power, it requires a noticably higher effort to achieve the same power level.

However I want to occasionally use the Kickr core WITHOUT the V3 pedals (and therefore no power match).
(I have had a look through the forum, but could not find quite the same question - It might be there but I have missed it).

What is the best way to do this?

  1. Change my FTP (This seems a bit drastic and philosophically wrong)
  2. Do the adjustment by changing the effort level of the session (ie running at, say, 95% rather than 100%)
  3. A third option I have not spotted yet? ie is there a way to frig the effective kickr core power?

I have discussed the problem with Wahoo and they say it is all down to drive train losses. However, I can feel a noticable difference between the two settings, the V3 pedals and the kickr power, especially at higher levels and around FTP/threshold.

Hence my question - advice appreciated please.



The only trouble with option 2 is that the variation may be significantly different at different intensities. E.g. 200W might be 10W difference, but 400W be 50W out. Which your post suggests is the case.

If you can, maybe record a ride with a variety of intervals in your different zones (build a load of 30-60 second intervals in workout creator). Record the Vectors on TR and the Kickr Core on a head unit, then compare the average wattage during the intervals.

You can then know what to reduce it by, e.g. sweetspot intervals at 95% intensity, anaerobic at 90%, etc.

If you go into Devices > Kickr > Settings: can’t you set an offset somewhere? I thought I saw it there once, but I’m not near my trainer now so I can’t check it at the moment…

EDIT: just searched around a bit, if you set powermatch to manual, you can set an offset… but I don’t know if it will work when you are not using the pedals…

Agreed Martin, Yes, I am seeing more of a constant difference, not a proportional one (which puzzles me). or rather the proportion is not consistently growing. That is a problem I would face and would like to avoid. (Ideally the darn things would match and I would not need a fudge)

same exact issue with Stages crank PM

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I have the same issue with my dual leg Pioneer PM and Tacx Neo. When I ride with Power Match and user Pioneer as power source, workouts seem to be much easier and thats why I don’t use it :slight_smile:

I keep it with Neo at ERG mode keep challenging myself. Then it feels much easier outdoors.

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I actually just tested mine yesterday doing some VO2max intervals. I use Favero Assioma Duo. The results are these (both calibrated right before the ride):

Kickr Assioma Difference
Warmup 139 132 5,3 %
Warmup interval 358 332 7,8 %
Interval 1 343 329 4,3 %
Interval 2 348 329 5,8 %
Interval 3 326 314 3,8 %
Interval 4 324 314 3,2 %
Interval 5 326 313 4,2 %
Break 107 105 1,9 %
Interval 6 335 318 5,3 %
Interval 7 328 315 4,1 %
Interval 8 323 311 3,9 %
Interval 9 315 315 0,0 %
Interval 10 312 312 0,0 %

Between interval 8 and 9 I changed TR to use powermatch (and didn’t look beyond interval 10 since the rest was with powermatch). Riding at about 125 % rather than 120 % was brutal, especially right after an FTP test.
As @martinheadon said I’ll be doing some more test with threshold and sweetspot work. Just to make sure I get the right factors.

If I’m using a bike without the pedals in the future, I’ll be setting FTP down by 4.5 % so that I get the right amount of TSS. You’d get the same result by riding at 96 % intensity, but the TSS will be off. And that’s what matters in the long run, not what FTP you rode at.


I may do the same test today. If do, I will share the results.

I’ve got a similar issue with a Stac Halcyon and Stages single sided PM. You can adjust the Halcyon to match the Stages using the 2 different Average Power readings from a workout. The problem is I adjust the Stac and the next (similar) workout is still out. Adjust again with the same result and so on. It’s driving me nuts. I 'm away at the moment but when I get back next week in going to be a bit more scientific about it with exactly the same workout (modified Baxter with a couple of SS and VO2 max intervals thrown in. I’m also thinking using PowerSchool might be distorting the results. How though I don’t know.

With the vectors you can set a ‘factor’ (use the Garmin app) which maybe can help you get the power numbers closer.

What I would love TR to do, would be to remember all the power meters you use (they have an ID) and then allow you to set the FTP for each PM.

I know it is a bit of a first world problem having multiple power meters :slight_smile:

Maybe completely wrong here, do we not have a wind setting in the wahoo app, it alters the response curve of the kickr, but this setting is outside what TR controls. People do this on Zwift to get power when going downhills, otherwise they spin out. I think it needs to be set and the app closed - good for that single session, I think.

What app did you use to compare trainer and power outputs?