Cycling and bicycle discussion forums. 
   Click here to join our community Log in to access your Control Panel  


Go Back   > >

"The 33"-Road Bike Racing We set this forum up for our members to discuss their experiences in either pro or amateur racing, whether they are the big races, or even the small backyard races. Don't forget to update all the members with your own race results.

Reply
 
Thread Tools Search this Thread
Old 08-30-13, 07:35 AM   #1
skinnyguy 
Senior Member
Thread Starter
 
skinnyguy's Avatar
 
Join Date: Aug 2006
Location: Ontario, Canada
Bikes:
Posts: 249
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.
skinnyguy is offline   Reply With Quote
Old 08-30-13, 07:56 AM   #2
Creatre
These Guys Eat Oreos
 
Creatre's Avatar
 
Join Date: Jun 2010
Location: Atlanta, GA
Bikes: Yes
Posts: 3,422
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.
Creatre is offline   Reply With Quote
Old 08-30-13, 08:11 AM   #3
MDcatV
Senior Member
 
Join Date: Dec 2006
Bikes:
Posts: 6,760
262
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.
MDcatV is offline   Reply With Quote
Old 08-30-13, 08:59 AM   #4
waterrockets 
Making a kilometer blurry
 
waterrockets's Avatar
 
Join Date: May 2006
Location: Austin (near TX)
Bikes: rkwaki's porn collection
Posts: 26,130
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?
waterrockets is offline   Reply With Quote
Old 08-30-13, 09:13 AM   #5
mattm
**** that
 
mattm's Avatar
 
Join Date: Dec 2006
Location: CALI
Bikes:
Posts: 13,553
465w to go 45 km/h??

how much does uwe weigh?
__________________
cat 1.

blog
mattm is offline   Reply With Quote
Old 08-30-13, 09:26 AM   #6
waterrockets 
Making a kilometer blurry
 
waterrockets's Avatar
 
Join Date: May 2006
Location: Austin (near TX)
Bikes: rkwaki's porn collection
Posts: 26,130
154 lbs. at 5'11"

28mph on the bar tops with no gravity/tailwind help? That's going to be nasty.
waterrockets is offline   Reply With Quote
Old 08-30-13, 10:08 AM   #7
skinnyguy 
Senior Member
Thread Starter
 
skinnyguy's Avatar
 
Join Date: Aug 2006
Location: Ontario, Canada
Bikes:
Posts: 249
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
skinnyguy is offline   Reply With Quote
Old 08-30-13, 10:16 AM   #8
waterrockets 
Making a kilometer blurry
 
waterrockets's Avatar
 
Join Date: May 2006
Location: Austin (near TX)
Bikes: rkwaki's porn collection
Posts: 26,130
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.
waterrockets is offline   Reply With Quote
Old 08-30-13, 10:28 AM   #9
Racer Ex 
Resident Alien
 
Racer Ex's Avatar
 
Join Date: Jul 2007
Location: Location, location.
Bikes:
Posts: 12,446
I am plotting a tree height graph:

Racer Ex is offline   Reply With Quote
Old 08-30-13, 10:48 AM   #10
aaronmcd
Senior Member
 
aaronmcd's Avatar
 
Join Date: Aug 2013
Location: SF Bay Area, CA
Bikes: Cervelo S2, Ultegra 6700
Posts: 2,354
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.
aaronmcd is offline   Reply With Quote
Old 08-30-13, 11:01 AM   #11
mattm
**** that
 
mattm's Avatar
 
Join Date: Dec 2006
Location: CALI
Bikes:
Posts: 13,553
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
mattm is offline   Reply With Quote
Old 08-30-13, 11:20 AM   #12
Racer Ex 
Resident Alien
 
Racer Ex's Avatar
 
Join Date: Jul 2007
Location: Location, location.
Bikes:
Posts: 12,446
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.
Racer Ex is offline   Reply With Quote
Old 08-30-13, 11:29 AM   #13
aaronmcd
Senior Member
 
aaronmcd's Avatar
 
Join Date: Aug 2013
Location: SF Bay Area, CA
Bikes: Cervelo S2, Ultegra 6700
Posts: 2,354
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.
aaronmcd is offline   Reply With Quote
Old 08-30-13, 11:29 AM   #14
RChung
Senior Member
 
Join Date: Sep 2009
Bikes:
Posts: 1,020
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?

Attached Images
File Type: png watts-cda.png (10.0 KB, 38 views)
RChung is offline   Reply With Quote
Old 08-30-13, 11:52 AM   #15
echappist 
fuggitivo solitario
 
Join Date: Jun 2009
Location: Arlington, VA
Bikes:
Posts: 8,666
i think what he wants is a CdA estimator
echappist is offline   Reply With Quote
Old 08-30-13, 11:58 AM   #16
Racer Ex 
Resident Alien
 
Racer Ex's Avatar
 
Join Date: Jul 2007
Location: Location, location.
Bikes:
Posts: 12,446
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.
Racer Ex is offline   Reply With Quote
Old 08-30-13, 12:30 PM   #17
Hermes 
Elite Rider
 
Hermes's Avatar
 
Join Date: Oct 2006
Location: San Francisco Bay Area
Bikes: Too Many
Posts: 9,657
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.
__________________
We are what we repeatedly do. Excellence, then, is not an act, but a habit. Aristotle

Cat: Killer
Hermes is offline   Reply With Quote
Old 08-30-13, 12:35 PM   #18
RChung
Senior Member
 
Join Date: Sep 2009
Bikes:
Posts: 1,020
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.
RChung is offline   Reply With Quote
Old 08-30-13, 12:37 PM   #19
skinnyguy 
Senior Member
Thread Starter
 
skinnyguy's Avatar
 
Join Date: Aug 2006
Location: Ontario, Canada
Bikes:
Posts: 249
Thread : Fail
skinnyguy is offline   Reply With Quote
Old 08-30-13, 01:09 PM   #20
waterrockets 
Making a kilometer blurry
 
waterrockets's Avatar
 
Join Date: May 2006
Location: Austin (near TX)
Bikes: rkwaki's porn collection
Posts: 26,130
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.
waterrockets is offline   Reply With Quote
Old 08-30-13, 01:15 PM   #21
RChung
Senior Member
 
Join Date: Sep 2009
Bikes:
Posts: 1,020
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.
RChung is offline   Reply With Quote
Old 08-30-13, 01:23 PM   #22
waterrockets 
Making a kilometer blurry
 
waterrockets's Avatar
 
Join Date: May 2006
Location: Austin (near TX)
Bikes: rkwaki's porn collection
Posts: 26,130
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.
waterrockets is offline   Reply With Quote
Old 08-30-13, 02:18 PM   #23
Racer Ex 
Resident Alien
 
Racer Ex's Avatar
 
Join Date: Jul 2007
Location: Location, location.
Bikes:
Posts: 12,446
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
Racer Ex is offline   Reply With Quote
Old 08-30-13, 02:35 PM   #24
RChung
Senior Member
 
Join Date: Sep 2009
Bikes:
Posts: 1,020
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.
RChung is offline   Reply With Quote
Old 08-30-13, 02:50 PM   #25
Racer Ex 
Resident Alien
 
Racer Ex's Avatar
 
Join Date: Jul 2007
Location: Location, location.
Bikes:
Posts: 12,446
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.
Racer Ex is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -6. The time now is 05:06 AM.