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  1. #1
    Senior Member skinnyguy's Avatar
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    TT Speed vs Wattage data collection! Please Contribute

    I am trying to collect some data on TT speeds vs a given wattage to make a plot graph. If you can post your results w/ the following info that would help me a lot:

    Avg wattage
    Avg speed
    Bike set-up (tt w/ disc, no disc deep front wheel, bottles etc.)
    Your position (good, fair, bad)
    Course profile (flat, hilly, etc)
    Distance
    Your info (weight, type of clothing, helmet etc)

    thanks in advance for all who contribute.

  2. #2
    These Guys Eat Oreos Creatre's Avatar
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    There are sooooooooooooo many variables for this that go far beyond what you are asking for in order to get anything close to accurate/useful information.
    Category 2 | | Velogames BikeForums Leagues: 1st - 2012 Veulta, 1st - 2011 Vuelta, 2nd - 2013 Vuelta, 3rd - 2012 Giro, 4th - 2012 TdF

  3. #3
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    25.8
    tt bike (orbea ordu) w zipp disc on back and am class 58 on front, both tubular, normal water bottle on downtube
    fair
    flat and windy, circuit, 1st 10K mostly tailwind, mid 20K mix, last 10K into wind
    40K
    153#, skinsuit, giro advantage 2 helmet
    time 57:47
    Last edited by MDcatV; 08-30-13 at 08:16 AM.

  4. #4
    Making a kilometer blurry waterrockets's Avatar
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    This is as good as it's going to get:

    Quote Originally Posted by slvoid View Post
    I ripped this off of someone else who ripped it off of someone else who translated this month's issue of Tour magazine.

    They put Uwe Peschel on a normal bike:

    Needed Watts for Speed = 45 km/h :
    Stevens San Remo bike with normal handlebar 465 Watts needed to go 45 km/h
    Same bike Hands down the drops: 406 watts needed
    Same bikeEaston Aeroforce bar: 369 Watts
    Same bike Triathlon position (5.5 cm lower bar, saddle forwards): 360 Watts
    Same bike Triathlon position (5.5 cm lower bar, saddle forwards) and
    carbon Tri spoke wheels front and rear: 345 Watt

    Cervelo + Tri spoke front 328 Watts
    Cervelo + Tri spoke front + disk rear wheel : 320
    Cervelo + Tri spoke front + disk rear wheel +Giro helmet: 317
    Cervelo + Tri spoke front + disk rear wheel +Giro helmet + speed suit: 307
    Cervelo + Tri spoke front + disk rear wheel +Giro helmet + speed suit +
    saddle 3 cm further back: 293 Watts

    From 465 to 293 watts... That's a lotta savings.
    /thread?

  5. #5
    **** that mattm's Avatar
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    465w to go 45 km/h??

    how much does uwe weigh?
    cat 1.

    blog

  6. #6
    Making a kilometer blurry waterrockets's Avatar
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    154 lbs. at 5'11"

    28mph on the bar tops with no gravity/tailwind help? That's going to be nasty.

  7. #7
    Senior Member skinnyguy's Avatar
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    Quote Originally Posted by Creatre View Post
    There are sooooooooooooo many variables for this that go far beyond what you are asking for in order to get anything close to accurate/useful information.
    the whole idea is that if I can get a lot of contributions when it is all plotted you can start to see some trends.

    thanks MDcatV

  8. #8
    Making a kilometer blurry waterrockets's Avatar
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    Quote Originally Posted by skinnyguy View Post
    the whole idea is that if I can get a lot of contributions when it is all plotted you can start to see some trends.

    thanks MDcatV
    Even with data from everyone who has a TT bike and a power meter, there's too much variability. There are people who are more aerodynamic in the drops than aero bars. There are people who lose way too much power in the aero postition b/c they don't train there enough. How you hold your helmet, where you place your hands, shoe covers, skinsuit with a collar or not, humidity/dry, wind conditions, loops vs. out and back, pacing on the hills and headwinds. Too many variables.

  9. #9
    Resident Alien Racer Ex's Avatar
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    I am plotting a tree height graph:


  10. #10
    Senior Member aaronmcd's Avatar
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    Quote Originally Posted by waterrockets View Post
    Even with data from everyone who has a TT bike and a power meter, there's too much variability. There are people who are more aerodynamic in the drops than aero bars. There are people who lose way too much power in the aero postition b/c they don't train there enough. How you hold your helmet, where you place your hands, shoe covers, skinsuit with a collar or not, humidity/dry, wind conditions, loops vs. out and back, pacing on the hills and headwinds. Too many variables.
    Too many variables? Welcome to science. Collect data, control for what you can, account for what you can, pay attention to variance and statistical significance. With enough data you can still determine that with 'A' setup, 'B' position, 'C' power, 'D' conditions, 'E' size/weight → then you have x percent chance of being between y and delta y speed.

    Somehow I doubt there is going to be a comprehensive statistical analysis though.

    There are also a ton of variables for "tree height", but you could still plot tree height vs. location, climate, elevation etc and get a pretty good idea.

  11. #11
    **** that mattm's Avatar
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    The real question is (to me), say you get all the data you're looking for, then what?

    How would it help skinnyguy get faster in TTs?

    I think the best way to do that is for him to do his own testing, and figure out the faster positions/etc.
    cat 1.

    blog

  12. #12
    Resident Alien Racer Ex's Avatar
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    Quote Originally Posted by aaronmcd View Post
    Welcome to science
    There's a difference between science and a Sisyphean endeavor. There are people out there (raises hand) who have been chasing the aero enigma for years, this is basically doing calculus by counting your toes by looking at your shoes then counting your socks.

    Trees can range from <1mm to 379 feet. There are billions of trees. Pretty easy graph to plot that tells us trees can range from <1mm to 379 feet.
    Last edited by Racer Ex; 08-30-13 at 11:35 AM.

  13. #13
    Senior Member aaronmcd's Avatar
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    Quote Originally Posted by Racer Ex View Post
    There's a difference between science and a Sisyphean endeavor. There are people out there (raises hand) who have been chasing the aero enigma for years, this is basically doing calculus by counting your toes.

    Trees can range from <1mm to 379 feet. There are billions of trees. Pretty easy graph to plot that tells us trees can range from <1mm to 379 feet.
    I can tell you there are no 300 ft trees in the Phoenix area. I can also tell you there are no 20 year old trees under 1 mm. With data I bet I could improve those predictions.

  14. #14
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    Quote Originally Posted by skinnyguy View Post
    I am trying to collect some data on TT speeds vs a given wattage to make a plot graph.
    You mean, something like this?

    watts-cda.png

  15. #15
    fuggitivo solitario echappist's Avatar
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    i think what he wants is a CdA estimator

  16. #16
    Resident Alien Racer Ex's Avatar
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    Quote Originally Posted by aaronmcd View Post
    I can tell you there are no 300 ft trees in the Phoenix area. I can also tell you there are no 20 year old trees under 1 mm. With data I bet I could improve those predictions.
    Which has zero application to the subject at hand.

    I can pedal the exact same bicycle in static external conditions and have my CdA vary by 20%. Now add in 360 degrees of wind direction and the human morphological differences over equipment changes. Many of which have a effect on how the other things might behave.

    I'm just an idiot bike racer, with a few hundred hours of testing with some of the biggest brains in that field. I'm sure you know better how to control a few million points of variability to come up with something meaningful from a random Internet survey.

    Do tell.

  17. #17
    Elite Rider Hermes's Avatar
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    Quote Originally Posted by mattm View Post
    The real question is (to me), say you get all the data you're looking for, then what?

    How would it help skinnyguy get faster in TTs?


    I think the best way to do that is for him to do his own testing, and figure out the faster positions/etc.
    +1 unless this is some type of science fair project or paper. I suggest wind tunnel, Velo Sports Center aero testing or coast down testing to find out optimum position and equipment configuration. I did the Velo Sports Center aero testing option. My session was similar to this guys except along with body position, I tested a lot of different equipment such as wheels, helmets and skinsuits.
    "Insanity: doing the same thing over and over again and expecting different results." Einstein

  18. #18
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    Quote Originally Posted by Hermes View Post
    +1 unless this is some type of science fair project or paper. I suggest wind tunnel, Velo Sports Center aero testing or coast down testing to find out optimum position and equipment configuration. I did the Velo Sports Center aero testing option. My session was similar to this guys except along with body position, I tested a lot of different equipment such as wheels, helmets and skinsuits.
    Or you can test on the road with a power meter if you can find a traffic-free wind-free venue.

  19. #19
    Senior Member skinnyguy's Avatar
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    Thread : Fail

  20. #20
    Making a kilometer blurry waterrockets's Avatar
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    Quote Originally Posted by RChung View Post
    Or you can test on the road with a power meter if you can find a traffic-free wind-free venue.
    You can also go with other wind-tunnel substitutes, hoping for the best. Like riding next to someone with a meter and a static position, then comparing power files. I think you could do OK with a strain-gauge power meter combined with an iBike iAero, but I haven't tried it -- seems reasonable though, and would require windless routes.

    Quote Originally Posted by skinnyguy View Post
    Thread : Fail
    lol forgone conclusion. That's why I posted the Peschel data, not much other data will come out of this thread.

  21. #21
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    Quote Originally Posted by waterrockets View Post
    You can also go with other wind-tunnel substitutes, hoping for the best. Like riding next to someone with a meter and a static position, then comparing power files. I think you could do OK with a strain-gauge power meter combined with an iBike iAero, but I haven't tried it -- seems reasonable though, and would require windless routes.
    The virtue of the iBike is that you get mostly "real-time" feedback but the precision isn't quite as good as relying solely on an accurate power meter. That means it appears to work fine for some things but not for small differences in equipment. BTW, the Stages uses strain gauges but I wouldn't use it for this type of application.

  22. #22
    Making a kilometer blurry waterrockets's Avatar
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    Good point. I was going to say torque-based PM, but I wanted to leave the possibility open for the Garmin

    With more people trying it, I wonder how the side-by-side thing would pan out. Would really depend a lot on steady speeds, I suppose, to get acceleration differences out of it as much as possible.

  23. #23
    Resident Alien Racer Ex's Avatar
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    BTW, what he's doing isn't science, it's statistics.

    I was wholly impressed with the set up at the LA Velodrome. While you lose the ability to have controlled yaw it's otherwise probably the best "real world" thing going. Being able to see how noisy the rider is and to get all the parts in motion and loaded as they would be on the road is not something to sneeze at, and it gives you a sum total of the parts (CdA, mechanical friction, Crr, Etc) that you don't get in the tunnel.

    Maybe Chung can use that big brain to design a robotic tracking fan to simulate yaw

  24. #24
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    Quote Originally Posted by Racer Ex View Post

    I was wholly impressed with the set up at the LA Velodrome.
    Yeah, it's pretty damn cool, ain't it?

    Yaw isn't actually zero in there: there's non-zero yaw in the turns, and the actual amount of yaw will depend on how fast the rider is going. That was a neat trick to model. And, um, as for the other thing you mentioned that has come up, too.

  25. #25
    Resident Alien Racer Ex's Avatar
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    Quote Originally Posted by RChung View Post
    Yeah, it's pretty damn cool, ain't it?

    Yaw isn't actually zero in there: there's non-zero yaw in the turns, and the actual amount of yaw will depend on how fast the rider is going. That was a neat trick to model. And, um, as for the other thing you mentioned that has come up, too.
    Yeah, I figured the turns would create yaw and there would be variability for that both in speed and how high/low you were up on the apron. My model for this was made out of popsicle sticks, toothpicks, and Elmers.

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