Dc rainmaker analyzer - TrainerRoad IOS APP+Watt Bike Pro v Wahoo Elemnt Roam+Assioma (Dual)


Can anyone help resolve some knowledge gaps for me so that I can attempt to develop a workaround to a problem I am having with training data and power meters / recording devices/algorithms.


The above link is a link to a the DC alayzer tool comparing the same ride on two power meters and on 3 devices:

TrainerRoad ios runnning workout IndianHouse -3 connected to my watt bike pro
Zwift (PC) connected to my Watt Bike Pro
same ride on my Watt Bike Pro, using Elemnt Roam connected to my Assioma Duo power pedals

Whilst apparently not necessary on the Watt Bike Pro, before riding, I have calibrated it to a zero state using a setting on the bike itself. Firmware is up to date.

I expected power numbers between the same ride on TR and Zwift - (as they are on the same power meter -the watt bike) to be similar, if not identical! There are differences. Are these to do with data sampling time differences and algorithms used by the two different platforms? Which one is ‘right’? The Watt Bike Pro has cranks of 170mm but I cannot find anywhere in the apps to set this. What do the apps and particularly TR, assume the crank length to be for inside riding?

The assioma duo’s have the latest firmware, have the crank length set at 170mm and were calibrated before riding. They have been fitted to the WB with the washer which definitely looks like is needed. In my view, the difference between the Power figures in the TR file and the Elemnt Roam/Assioma duo is a concern. The differences are greater at higher target power numbers.

80% of my riding is indoors on the WB and my FTP etc is derived from TR based WB riding. BUT if I use this FTP outside with the Roam/Assiomas, when targeting (say) 220 watts the Assiomas will say around 200 (as in multiple places in this file) and this is going to drain me unnecessarily when trying to follow adaptive training or specifically a race pacing plan and post ride analysis. I know that I can change the assiomas to read higher to try and match the WB but it seems to be accurate for lower power numbers.

Has anyone else been down this specific rabbit hole with this specific equipment? Which direction were your differences and what was your solution?

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Hello! :wave:

This Tweet thread I posted a few weeks back might shed some light on things: https://twitter.com/gplama/status/1503589584953036801

1 - Likely answered by the Tweet thread above.

2 - WattBikes have never impressed me with power accuracy when put to the sword against a known/trusted secondary source.

The usual answer for these issues is to do more testing with other power meters. And to use the same recording device/device type for all meters so you’re not introducing recording differences.

A quick tip with the DCR Tool - If you’re using the same HR sensor on all recoding devices, line the datasets up using the HR data. (Files section → Edit → Enter a positive or negative offset in seconds).

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Hi Shane

Thanks so much for the speedy response, the DCR tip and also the twitter link - All, I’ve no doubt will help immensely - :grinning:

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