Power Meter Accuracy - Quarq, Assioma Duo & Tacx Neo

Triathlon Forum
1

I just purchased my first Quarq and have been testing accuracy vs. my Assiomas and Tacx Neo (OG).

I’ve done lots of testing …

Assioma’s pretty consistently show +5-15w vs. my Neo (~3%), and sometimes the variance is up to 0, sometimes 5%.
Quarq is showing +10-15w vs. my Assioma’s (another ~3%). I’ve only tested this 3 times now, but I’m always off…

I do most of my training indoors, so seeing a 30w bump outside is super impractical.

Anyone else deal with this? What do you do?

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2

First point is Tacx accuracy is garbage if you are on the big chainring. So, did you do your tests below 15 MPH on the Tacx? Assioma is usually lock-on with a Tacx at slow speeds. Fast speeds and the Tacx loses it.

3

Almost all my testing on tacx has been while racing

I’d guess <5% of time is slow
.

4

Then the Tacx data are not usable. If in the 20-25 MPH range, Tacx is just making it up.

5

Ah interesting

How about Assioma vs quarq?

6

Those two are generally considered best of breed. They should be close. But based on your posts and data from your thread a year ago, I suspect that you have a bad set of Assioma pedals.

7

If only there were a way to determine which of these was the closest to being right.

8

The one that reads the highest?

9

Have you tried calibrating them lately?

10

The one that reads the highest?
I guess I buried the lede again.

11

It doesn’t matter, does it? Set your preferred PM of Quarq or Assioma to control your Neo. Do an FTP test to set your baseline. Consistent power readings going forward.

12

It’s easy to set a PM to control zwift , but that’s not the point

I ride my bikes outside and on the trainer. I have different readings on each bike + trainer

13

Have you tried calibrating them lately?

Yup

I calibrate before every ride, and then usually once about 15 mins into the ride.

14

If only there were a way to determine which of these was the closest to being right.

Is there?

15

Those two are generally considered best of breed. They should be close. But based on your posts and data from your thread a year ago, I suspect that you have a bad set of Assioma pedals.

I had emailed Assioma and they basically said F-Off. not very helpful at all.

16

I would trust your Quark and your Tacx below 20 MPH.

17

Is there?
Originally, virtual elevation wasn’t developed as an indirect way to determine drag – it was developed as an indirect way to determine power meter accuracy.

18

Have you tried calibrating them lately?
Yup

I calibrate before every ride, and then usually once about 15 mins into the ride.

Setting zero /= calibration

19

Have you tried calibrating them lately?

Yup

I calibrate before every ride, and then usually once about 15 mins into the ride.

I may be mis-interpreting, but “calibrating” when accuracy issues are involved usually entails static calibration, not taring (aka performing zero-offset). What you are describing is a zero-offset, not a static calibration.

20

Is there something different I should be doing?