Power:weight ratios

Discussion in 'Pro Cycling (Road and Track Racing)' started by gbs, 24 May 2018.

  1. gbs

    gbs Über Member

    Location:
    Fulham
    Simon Yates, for example, climbs v quickly and therefore has a high power:weight ratio. However he is said to be a less successfu t/ter because he lacks power.

    Can someone explain please.
     
    Last edited: 26 May 2018
  2. Beebo

    Beebo Firm and Fruity

    Location:
    Hexleybeef
    Well he doesn’t weigh much so his power to weight ratio is high, even though his actual power output isn’t that high.

    Think the opposite of someone like Chris Hoy, who has huge power, but weighs a lot so has a poor power to weight ratio.
     
  3. marzjennings

    marzjennings Veteran

    For the same reason a hot hatch will beat a V8 muscle off the line, but get caught up eventually. Shifting an increased mass requires increased power and to produce more power you often need more mass, and unfortunalty the relationship isn’t linear.

    I ran a quick calc and if Simon is 58kg and is conditioned to ride an average of 350watt, then up a 10% incline he’ll manage 16.6kph and on the flat about 38kph. Now if he added on bit of muscle to produce more power, maybe getting up to averaging 400watts for a new weight of 70kg then he’ll be slower on the climbs at 16.3kph, but a bit quicker on the flat at 38.8kph. Which for a flattish course could mean the difference between winning or not.

    I use this power calc if I want to see the impact of power, mass, incline, etc on speed... http://www.kreuzotter.de/english/espeed.htm
     
    Soltydog and Bollo like this.
  4. Specialeyes

    Specialeyes Über Member

    Location:
    Essex
    To over-simplify: TTs tend to be flatter, so less of the rider's power is devoted to overcoming gravity and more of it is devoted to going very fast in a (relatively) straight line. Skipping past square-cube laws and aerodynamics, power in a TT is largely spent on overcoming wind resistance, which makes it more about absolute power rather than relative power.

    Emma Pooley, who knows a thing or two about both climbing and TTs, explains it better :smile:


     
    smutchin likes this.
  5. BalkanExpress

    BalkanExpress Veteran

    Location:
    Balkans

    Fact: the pixie Pictionary has a picture of Emma Pooley for the entry “myrhical small creature with near magical powers”
     
    jarlrmai likes this.
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