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Huge power dropoff on tri bike

RumpoleRumpole
in General Training Discussions

Trying to get used to the tri bike again.  To give some examples: ABP ride, road bike -- NP 208.  Best 1 hr, NP 218.  Same course on tri bike: NP 180 and considerably slower.  Has to be fit, right?

Comments

  • Scott AlexanderScott Alexander
    Is this your first ride on the tri bike? I have to allow several weeks after transitioning full time to the tri bike before I start to see anywhere near my road bike FTP. Different muscles!!
  • Tom GlynnTom Glynn
    Ubersence App has a great blog on bike fit. Take a few shots of your self and then run down the analysis here:

    http://blog.ubersense.com/2012/08/07/triathlon-bike-fit-seat-tube-angle/

    You'll see if fit is a huge issue.

    Tom
  • Joseph LombardiJoseph Lombardi

    Road bike and Tri Bike different geometry...expected different power numbers....like inside v outside....and Tri bike tends to be lower than Road bike...again due to the geometry...especially in the Aero position

    In the end  Its just a number...ride a while...check the fit...but either way...its just a number a metric...a training tool....don't get hung up on it being lower than your road bike.

  • mgraffeomgraffeo
    Could be fit, could be power meter calibration, could be just positional adaptation. Need to work through the process and start ruling things out.

    But, if you're going considerably slower on the tri bike, then something's clearly wrong. Could it be that you just weren't working as hard? Could there have been huge winds that day that really threw off your ability to focus on putting out some watts? Or could it be that on the tri bike, you can't see the computer as easily, and therefore weren't watching your 'whip' as often? Lots of possibilities to think through.
  • RumpoleRumpole

    Agree, but I've eliminated several.  For example: PM is fine -- zeroed out before every ride.  No huge winds on a given day, and even then it's the output that concerns me.  I can see the garmin fine.  

    Big change was I lowered the seat and slid it forward because it was killing me.  But now I'm not generating anywhere near close to the same power, and going slower.  I'm voting on fit...

  • rklingrkling
    Agree that it is most likely fit. Lowering the saddle doesn't usually result in a loss of power, but if the change is too extreme, I'm sure it can. Remember, too, that if you move your saddle forward, you are effectively lowering the seat height, so usually if you move the saddle forward, it should be raised. Conversely, if you slide your saddle back, it should be lowered to keep the same saddle height.

  • mgraffeomgraffeo
    Any updates after a weekend of riding? 28 watts difference from road bike to tri bike (~10%) should give similar speed, not considerably slower on tri bike (unless you're up on the hoods the whole time). Still believe there's something amiss with the data...
  • kimmydctkimmydct
    Just came across this...

    http://triathlon.competitor.com/2013/05/gear-tech/balancing-aerodynamics-and-power-in-your-bike-fit_75698
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