Huge difference between Assioma uno and kickr core

Got a new kickr core setup today and am scratching my head a little at the difference between power readings on my trusty Assioma uno and the kickr. The Assioma is reading 20-25% higher! Lol. But yeah. At a steady 200w on TrainerRoad using the Assioma the power from the kickr is about 160. That scales as I go up or down in power.

My drivetrain isn’t covered in mud or anything, but it is an older bike I don’t ride outside anymore and haven’t for years now.

I know the wisdom is to ignore the difference, but this is so big that it’s mentally messing with me. Short of buying a conversion kit to turn my uno into a duo, is there any other sanity check I can perform?

If you’re only riding this bike indoors, then why not just use the kickr core numbers?

Should mention that the pedals get transferred to my outdoor bike whenever I ride outside.

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In that case, I think the accepted wisdom is to use powermatch

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Yeah, which is what I’ll do. Just my own vanity wondering if my threshold is 300 or 230 haha.

I’m sure it’s 300 :wink:

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Double check your crank length setting on your head unit, and with the Assioma app.

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Yep, double check the crank length settings as road_wars has stated.

If that’s OK, then what I would do is the static weight test. Measure the weight on an accurate scale, or a scale with an accuracy rating for the weight range you will use.

If the KICKR is truly that far off, I would be seriously ticked and contact Wahoo. But, first, sanity check everything you can. It’s entirely possible that you have a big leg bias as well. I’m struggling with that right now too. Upwards of 41L/59R now. I will need to do a static weight test to be sure my Duo is not having issues.

Edit: I am assuming that you calibrated the KICKR after a warmup period.

How accurate do the weights need to be for the static test? Would dumbbell weights suffice?

I expect for comparative purposes (Left vs Right) it does not matter too much. For this purpose, can you get the answer without accepting the calibration adjustment?

They will. You just need to know what they actually weigh. And you will need a repeatable method to tie it to the pedal.

The reason you need to know the weight as that the Assioma will report the weight back to you, and by confirming/scaling you will calibrate it to that weight. So, it’s best that you know, accurately, what you’re dealing with.

On the DUO, you can then see (just by measuring and not calibrating) if they are close or not.

Favero Assioma Static Weight Test

Edit: I would probably weight the rope/chain/hooks in addition to the weight, as well.

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Can it be left/right imbalance + drivetrain loss?

Assioma are known to be quite accurate, maybe try with a friend’s trainer?

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It can.

But, I would still check. Though Assioma is generally good, they do have some failures. Some folks in the Assioma thread have experienced failures where it starts to go out slightly before a complete failure. It’s not a frequent occurrence or often reported, but it has been reported. I think one of the online reviewers had problems. I can’t recall if it was DCR or GPLama, or Tariq from Smart Bike Trainers.

It troubled me enough to buy the extended warranty.

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I have the same issue. I use power match for TR. but the kicker is connected to Zwift so I can see the power numbers on Zwift. What I’ve noticed is that the higher the gear, the closer the kicker power gets to my Assiomas. If I am in the small chain ring, the difference is large. But when I’m in big ring and on 15 in the back, the numbers match. So if I want to PR a climb or race, I put my gear on 11 cassette.

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The power meter that reads higher is always right! :grinning:

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actually want to try this, from my limited sample size last night that is somewhat true for me too, gearing seemed to affect it.

Thanks all. I plan on doing the static weight test sometime this week, and maybe springing for a duo upgrade to my assioma later this summer just as a sanity check. My old tacx vortex was higher than the pedals, then I got a Saris M2 that read a lot lower than the pedals/about the same as this new Kickr.

That alone would make me think that the trainers are right, but then theres the other fact that I have an old powertap hub that I put on the trainer as well to sanity check, and it reads much closer to the pedal, about 5-10% lower. that could easily be leg imbalance or a worn drivetrain.

In the end I have 2 smart trainers agreeing with each other and 2 power meters more or less agreeing. I’m tempted to go with the power meters and call it a day.

If you use the Assioma outside then i would just go with that and not even look at the Core numbers.

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So, to follow up on this, I think the trainer is actually reading low. I went on strava, looked at my best time for a longish (20min) 12% grade steady climb where the power had been recorded by the assioma, and noted that power. I went to Best Bike Split, uploaded that segment gpx, and entered my power. The estimated finish time was within seconds over 20 min. So, whatever’s causing the kickr to read so much lower, I don’t think it’s accurate. I am left leg dominant, and I don’t doubt that that’s part of it too.

What’s that saying about a man with too many clocks?