Page 1 of 2 12 LastLast
Results 1 to 25 of 35
  1. #1
    RoadBikeReview Member
    Reputation:
    Join Date
    Jun 2011
    Posts
    177

    Estimates of power without a meter?

    So, I've been trying to figure out if I'm any good. I've been using this to estimate power at the moment, but it would be great if you all would tell me whether or not this amounts to anything other than an estimate with a 50% error bar.

    I started working on getting in pretty decent shape a couple months ago, starting at a weight of 197 pounds. I weigh 175 now, but I'm aiming for more like 150-155. I'm 5'9".

    I just use various times where I pay close attention to the wind based on how it feels both directions (often I will look at hourly weather data and even calculate the head wind using trigonometry), use Map My Ride for elevation.

    It's also unclear on aerodynamics because the stem on my bike is higher than on a bike one would prefer for racing.

  2. #2
    RoadBikeReview Member
    Reputation: Pirx's Avatar
    Join Date
    Aug 2009
    Posts
    2,470
    I looked at the site you linked to, and this looks like it gives you as good an estimate as possible with the limited amount of information available. Those numbers should be in the ballpark, and certainly better than within 50%. I would guess that chances are you're going to be within 10%. Whether or not that helps you figure out if you're "any good" is a very different question.

  3. #3
    RoadBikeReview Member
    Reputation:
    Join Date
    Mar 2006
    Posts
    334
    It looks a little high to me. I ride with a power. I plugged my numbers in and at 200 watts it said I'd be going 17.3 mph. In my experience I'd be right around 20 mph at 200 watts. I'll have to go back and check my logs but I think I'd only be putting out 150 - 160 watts at 17ish mph.

    So I'd say it's within 25%.

  4. #4
    RoadBikeReview Member
    Reputation: DaveWC's Avatar
    Join Date
    Sep 2012
    Posts
    651
    It calculates too much power (as much as 25% too much) for my rides even when assuming zero wind.

  5. #5
    RoadBikeReview Member
    Reputation: dougclaysmith's Avatar
    Join Date
    Oct 2009
    Posts
    3,882
    I wonder if this is how Strava does it. I do not have a power meter, but Strava figures something on my rides. I always wondered were they got those numbers from.

  6. #6
    RoadBikeReview Member
    Reputation:
    Join Date
    Nov 2004
    Posts
    8,605
    Quote Originally Posted by dougclaysmith View Post
    I wonder if this is how Strava does it. I do not have a power meter, but Strava figures something on my rides. I always wondered were they got those numbers from.
    they get your height, weight bike type straight from the government databases. From there on it's easy.
    Blows your hair back.

  7. #7
    Moderatus Puisne
    Reputation: Argentius's Avatar
    Join Date
    Aug 2004
    Posts
    16,090
    We all want to figure out if we are "any good," but, non-metered guesses at power, even with some of the cyclometers out there which have a "power" feature, but no strain gauges, are pretty bad.

    It's mostly just guessing. It will give you a ballpark in the right significant figure -- you know, if they say 300 watts, you're probably not doing 150 or 600 -- but not close enough to compare with other cyclists.

    OTOH, if you know you've reduced your time by, say, 30 seconds, on a given climb, you might be able to roughly figure out how much power INCREASE that represents.

  8. #8
    RoadBikeReview Member
    Reputation:
    Join Date
    Nov 2004
    Posts
    8,605
    Quote Originally Posted by Argentius View Post
    We all want to figure out if we are "any good," but, non-metered guesses at power, even with some of the cyclometers out there which have a "power" feature, but no strain gauges, are pretty bad.

    It's mostly just guessing. It will give you a ballpark in the right significant figure -- you know, if they say 300 watts, you're probably not doing 150 or 600 -- but not close enough to compare with other cyclists.

    OTOH, if you know you've reduced your time by, say, 30 seconds, on a given climb, you might be able to roughly figure out how much power INCREASE that represents.
    or pick a steep slope >8%. ride next to one with a power meter and ask how many watts it reads and ask about the persons weight.
    Blows your hair back.

  9. #9
    RoadBikeReview Member
    Reputation:
    Join Date
    Apr 2006
    Posts
    245
    I've been using Sportracks software with this plugin and my Garmin 800. A bit futzy to set up, but the results seem to be internally consistent and I can track over time.

    It doesn't account for drafting, through, which makes me look like I'm putting out more power on group rides than on solo rides.

  10. #10
    Master debator.
    Reputation: nOOky's Avatar
    Join Date
    Mar 2009
    Posts
    7,387
    Power is highly over-rated. Just look down at your speedo when you're going fast and use that as you average speed and go from there.
    "I felt bad because I couldn't wheelie; until I met a man with no bicycle"

  11. #11
    RoadBikeReview Member
    Reputation:
    Join Date
    Nov 2004
    Posts
    8,605
    Quote Originally Posted by nOOky View Post
    Power is highly over-rated. Just look down at your speedo when you're going fast and use that as you average speed and go from there.
    we really don't want people cycling in a speedo pair do we?
    Blows your hair back.

  12. #12
    RoadBikeReview Member
    Reputation: dougclaysmith's Avatar
    Join Date
    Oct 2009
    Posts
    3,882
    Quote Originally Posted by den bakker View Post
    they get your height, weight bike type straight from the government databases. From there on it's easy.
    hmmm, I thought they got it when you loaded it in.

  13. #13
    RoadBikeReview Member
    Reputation:
    Join Date
    Nov 2004
    Posts
    8,605
    no that would be the current regime just checking your honesty. if the numbers you provide are not true it is noted for further use. Who knows what else people would be dishonest about then.
    Blows your hair back.

  14. #14
    Master debator.
    Reputation: nOOky's Avatar
    Join Date
    Mar 2009
    Posts
    7,387
    Quote Originally Posted by den bakker View Post
    we really don't want people cycling in a speedo pair do we?
    Visit any triathlon...
    "I felt bad because I couldn't wheelie; until I met a man with no bicycle"

  15. #15
    RoadBikeReview Member
    Reputation:
    Join Date
    Nov 2004
    Posts
    8,605
    Quote Originally Posted by nOOky View Post
    Visit any triathlon...
    ok. _I_ don't want to.
    YMMV.
    Blows your hair back.

  16. #16
    RoadBikeReview Member
    Reputation: looigi's Avatar
    Join Date
    Nov 2010
    Posts
    6,325
    Why does it matter if you're any good? Ride often, far, hard and fast. Train systematically if you want. Ride with others. Race. It's all fun. The only time it really matters if you're "any good" is if you're a pro or aspiring to be one.
    ... 'cuz that's how I roll.

  17. #17
    RoadBikeReview Member
    Reputation:
    Join Date
    Jun 2011
    Posts
    177
    It adds a layer to the enjoyment if you are a strong rider and riding a bike is a little bit more like riding a motorized vehicle due to sheer manpower.

  18. #18
    RoadBikeReview Member
    Reputation:
    Join Date
    Jun 2011
    Posts
    177
    Quote Originally Posted by nOOky View Post
    Power is highly over-rated. Just look down at your speedo when you're going fast and use that as you average speed and go from there.
    If power could be measured accurately and precisely, it wouldn't be overrated. It's the direct measurement of performance. Average speed is affected by elevation, wind, tire pressure, body weight, height, the friction in the bike's mechanisms, the height of your handlebars, the position you're riding in and probably more.

    The power your body exerts can be constant.

    Oh, and nice Kung Fu Hustle avatar.

  19. #19
    RoadBikeReview Member
    Reputation: nhluhr's Avatar
    Join Date
    Sep 2010
    Posts
    679
    Quote Originally Posted by Alkan View Post
    It adds a layer to the enjoyment if you are a strong rider and riding a bike is a little bit more like riding a motorized vehicle due to sheer manpower.
    That's what racing is for.

  20. #20
    RoadBikeReview Member
    Reputation:
    Join Date
    Jun 2011
    Posts
    177
    Quote Originally Posted by nhluhr View Post
    That's what racing is for.
    Yes, and that's my end goal. I'm just trying to gauge how I am right now. I'm not ready to enter competitive races just yet.

  21. #21
    RoadBikeReview Member
    Reputation: nhluhr's Avatar
    Join Date
    Sep 2010
    Posts
    679
    Quote Originally Posted by Alkan View Post
    Yes, and that's my end goal. I'm just trying to gauge how I am right now. I'm not ready to enter competitive races just yet.
    Well, you might not be ready to win but there's no reason you can't go try a Cat5 road race and see how you do. Besides, if you like it, you'll wish you started sooner so you can have more upgrade credits under your belt.

  22. #22
    Master debator.
    Reputation: nOOky's Avatar
    Join Date
    Mar 2009
    Posts
    7,387
    Whoooosh


    Quote Originally Posted by Alkan View Post
    If power could be measured accurately and precisely, it wouldn't be overrated. It's the direct measurement of performance. Average speed is affected by elevation, wind, tire pressure, body weight, height, the friction in the bike's mechanisms, the height of your handlebars, the position you're riding in and probably more.

    The power your body exerts can be constant.

    Oh, and nice Kung Fu Hustle avatar.
    "I felt bad because I couldn't wheelie; until I met a man with no bicycle"

  23. #23
    RoadBikeReview Member
    Reputation: spade2you's Avatar
    Join Date
    May 2009
    Posts
    11,696
    Quote Originally Posted by Alkan View Post
    Yes, and that's my end goal. I'm just trying to gauge how I am right now. I'm not ready to enter competitive races just yet.
    Then keep training, have a training plan, and get a power meter when you can regardless of racing status.

  24. #24
    RoadBikeReview Member
    Reputation:
    Join Date
    Feb 2002
    Posts
    19,480
    Quote Originally Posted by Alkan View Post
    So, I've been trying to figure out if I'm any good. I've been using this to estimate power at the moment.
    That site gives notoriously high numbers. Go to analyticcycling.com for accurate estimates.

  25. #25
    RoadBikeReview Member
    Reputation:
    Join Date
    Jul 2007
    Posts
    502
    Here is some benchmark:
    http://app.strava.com/762361261
    First 4 guys have power meters.

Page 1 of 2 12 LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

2015 LIGHTS SHOOTOUT

Hot Deals See All Hot Deals >>

Interbike Featured Booths

Check out the hottest road bike products from these brands!



















See All Interbike Coverage - Click Here »


Latest RoadBike Articles


Latest Videos

RoadbikeReview on Facebook