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Gradient Formula Help please

berlinerberliner Posts: 340
I just climbed a hill 1.71 k length total climb 137 meters.
How do I work out the the average gradient?
An excel formula would be great.
Thanks

Posts

  • GiantMikeGiantMike Posts: 3,139
    edited June 2011
    Cell A1 enter 1710
    Cell A2 enter 137
    Cell A3 enter '=A2/A1*100" (ignore the speech marks)

    Answer should be around 8%

    Cell A3 enter the combined weight of the bike and you in kgs
    Cell A4 enter "=A3*9.81*A2" (this in how many kilojoules you used, and is roughly the calories used too)
    Cell A5 enter the time taken in seconds to climb the hill
    Cell A6 enter "A4/A5" (this is the average watts you produced over the climb

    I can build you an excel spreadsheet if you like. PM me your email address and I'll do it tonight.
  • danowatdanowat Posts: 2,877
    Height gain divided by distance travelled * 100

    e.g

    137 / 1710 * 100 = 8.01%

    edit : beaten to it! 8)
  • PepPep Posts: 501
    GiantMike wrote:
    Cell A3 enter the combined weight of the bike and you in kgs
    Cell A4 enter "=A3*9.81*A2" (this in how many kilojoules you used, and is roughly the calories used too)
    Cell A5 enter the time taken in seconds to climb the hill
    Cell A6 enter "A4/A5" (this is the average watts you produced over the climb

    Interesting.
    I did not know that riding on the flat you use ZERO energy or power.
  • berlinerberliner Posts: 340
    Thanks for that and Giant mike thanks for that offer as well. I may come back to you on that.
  • GiantMikeGiantMike Posts: 3,139
    Pep wrote:
    GiantMike wrote:
    Cell A3 enter the combined weight of the bike and you in kgs
    Cell A4 enter "=A3*9.81*A2" (this in how many kilojoules you used, and is roughly the calories used too)
    Cell A5 enter the time taken in seconds to climb the hill
    Cell A6 enter "A4/A5" (this is the average watts you produced over the climb

    Interesting.
    I did not know that riding on the flat you use ZERO energy or power.

    You don't (as you know), but on the flat all your power is consumed by the various drags and frictions. For a climb you can work out how much power is required to lift the weight a known distance, and from that make an assessment of power used. While not purely scientific, assuming the same hill and the same bike, it is a simple way to see if power is increasing through training.

    On my local hill I produce 350W power for 8 mins (measured with a PowerTap) of which 40W is drag/resistance (at a speed of 7mph). For different riders the drag figure will be different, but roughly constant to the individual over time so can be largely ignored.

    Hope that helps.
  • doyler78doyler78 Posts: 1,951
    GiantMike wrote:
    You don't (as you know), but on the flat all your power is consumed by the various drags and frictions. For a climb you can work out how much power is required to lift the weight a known distance, and from that make an assessment of power used. While not purely scientific, assuming the same hill and the same bike, it is a simple way to see if power is increasing through training.

    On my local hill I produce 350W power for 8 mins (measured with a PowerTap) of which 40W is drag/resistance (at a speed of 7mph). For different riders the drag figure will be different, but roughly constant to the individual over time so can be largely ignored.

    Hope that helps.

    If you have constrained all the variables then time alone would tell you same thing surely.
  • GiantMikeGiantMike Posts: 3,139
    Correct, time would allow you to compare fitness although it doesn't take into account changes in the weight of the rider/bike.
  • doyler78doyler78 Posts: 1,951
    GiantMike wrote:
    Correct, time would allow you to compare fitness although it doesn't take into account changes in the weight of the rider/bike.

    Ahh ok. I thought you had said you were assuming they were the same however I notice you only mentioned the ame bike so that leaves the riders weight as still possible to change. My bad :lol:
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