Huge difference between Assioma uno and kickr core

Equipment
1

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?

2

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

3

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

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4

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

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5

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

6

I’m sure it’s 300 :wink:

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7

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

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9

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?

11

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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13

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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14

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

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15

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

16

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.

17

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

1 Like
18

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?