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Power comparison with Vector 3 Pedals

muckymariner
over 5 years ago

Hi,

I got my 2T today and did my first ride using TrainerRoad. I used the 2T as the power source in Erg mode connected to TrainerRoad, with my Vector 3 pedals connected to my Edge 1030. There was a significant defference between the power readings of the two devices of between 15 and 20 watts; the Neo reading approx 245 and the Vectors closer to 260. A chart is attached showing hte two rides overlaid on one another.

Is there a problem, or is this normal? I don't know how the different readings are taken, but assume that they should be broadly similar across the range - the variation seems to great to be accounted for by devices at opposite ends of their tolderance ranges to me. Grateful for your thoughts?

https://analyze.dcrainm..aker.com/#/public/1095b96c-676d-43d7-6f98-40b0d3533806

Any advice would be gratefully accepted.

  • Former Member
    0 Former Member over 5 years ago in reply to FelipeSerra

    Actually you end up training harder if you rely on Tacx numbers ;) If your training wants you to do 250 watts for a period of time, on Tacx when it shows 250w you're actually pushing 270w. 

    Well you're probably not finishing your workouts cause you're super tired and blow up. So I guess you'd eventually detrain? LOL. 

    But yeah once you know Tacx 2T is inaccurate, might as well use your reliable power meter if you're lucky to own one on your bike like a pedal crank or spider based one.

  • Former Member
    0 Former Member over 5 years ago in reply to krazyeone

    I have done too many tests. Until I see a new firmware saying they addressed the power inaccuracy, I give up. I'll be using my other PM's.

  • 0 over 5 years ago in reply to krazyeone

    Thanks  for the tests.

    It seems there is a strong correlation between the two parallel measures... strange according to what other say.

    I quickly had a look, it seems the Neo2T is a little bit late (not always) compare to the second power meter device. Just a very small offet, otherwise pretty the same.

    And -0.83% on a 34min + race (and race is full of variations), is good. May be the issue is when switching between ERG vs SIM ?

    Thanks. 

  • 0 over 5 years ago in reply to Former Member

    No. You are wrong. When tacx shows 250w you are on 230w.

  • Former Member
    0 Former Member over 5 years ago in reply to FelipeSerra

    Are you really saying I'm wrong about what I own? Tacx shows ~20watts LESS than other PM's.

  • 0 over 5 years ago in reply to FelipeSerra

    I think you got the numbers mixed up. The Tacx is reading lower. To produce 250w at the Tacx flywheel you need to push 270w at the pedals. Assuming the Tacx is wrong you are actually working harder to produce 250w.

    That's why I'm using my PM for both indoor and outdoor training. Even if the PM is wrong and reading high at least it's consistent inside and outside.

  • 0 over 5 years ago in reply to Former Member

    so i Don´t get you, i don´t understand how you end up training harder if you only rely on Tacx if show less. that was i was trying to said, may be misunderstood 

  • Former Member
    0 Former Member over 5 years ago in reply to FelipeSerra

    Not everyone gets their FTP numbers on a trainer. For example, if I do a 20 min or 1 hour test outside with my 4iiii and plug my FTP number (let's say 250 watts) from that into my training software, then try to ride the prescribed watts on the training software with my tacx, I'd in reality be doing 270 watts when tacx is showing 250 watts. 

  • 0 over 5 years ago in reply to Former Member

    ??? sorry but still don´t get you. I mean, you have to compare power numbers, FTP it's just a parameter, could be 300, but if your power meter shows 270 and tacx shows 300 your are detraining, I always train on ERG mode, when 200w on trainerroad controlling the NEO, stages shows 170 - 180. It's always lower. FTP doesn´t matter....

  • Former Member
    0 Former Member over 5 years ago in reply to FelipeSerra

    yeah i don't think we'll be able to help you. good luck.