Advertise on Bikeforums.net



User Tag List

Page 1 of 2 12 LastLast
Results 1 to 25 of 49
  1. #1
    Peloton Dog patentcad's Avatar
    Join Date
    Nov 2005
    Location
    Chester, NY
    My Bikes
    2013 Scott Foil, 2009 Scott Addict R2, 2008 Cervelo P3 TT bike, 2008 Motobecane Fly Ti Hard Tail MTB
    Posts
    56,076
    Mentioned
    26 Post(s)
    Tagged
    1 Thread(s)

    TT aero advantage question

    In the TT I did Saturday most participants used regular bikes since it was mostly uphill. But there was one fast, flat section (I was doing 25mph or so) that was nearly a mile long. I'm curious: on a typical rolling TT of say 12 miles or so, how much faster would the aero position of a TT rig make you vs. a typical racing bike, expressed as time saved? 20 seconds? 40 seconds? There must be research on this stuff.

    I'm assuming this would be a minor factor on a mostly uphill course, but I'm sure anyone who had a TT rig would have used it on these roads Saturday (and they did), it was not all pure climbing.

  2. #2
    Texas Fight! UT_Dude's Avatar
    Join Date
    Oct 2006
    Location
    Austin, TX
    Posts
    2,023
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    You have Zipps, so you don't need any other aero advantage, remember??
    T E X A S F I G H T !
    http://www.chriscollins.org

  3. #3
    Theodore Roosevelt's idol TheKillerPenguin's Avatar
    Join Date
    Sep 2004
    Location
    Vagabond
    My Bikes
    Affirmative
    Posts
    9,002
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Probably a lot. You've zipps already though, so you're good to go

    I'm trying to finagle a deal on a TT bike, since I've got stage races coming up... I've been Merckxin it and my TT is strong like bull, at 25.7mph. I figure with Aerobars, aero helmet, skinsuit, aero position, and aero wheels I'll be doing some low level flying.
    Masochism is a training adaptation.

  4. #4
    Peloton Dog patentcad's Avatar
    Join Date
    Nov 2005
    Location
    Chester, NY
    My Bikes
    2013 Scott Foil, 2009 Scott Addict R2, 2008 Cervelo P3 TT bike, 2008 Motobecane Fly Ti Hard Tail MTB
    Posts
    56,076
    Mentioned
    26 Post(s)
    Tagged
    1 Thread(s)
    Quote Originally Posted by UT_Dude
    You have Zipps, so you don't need any other aero advantage, remember??
    Just answer the question.

    I doubt it's 'a lot', but with all the weenies here, there MUST be a link to some exhaustive study with graphs and charts.

    The first person that says 'lose 5lbs and get a PowerTap' gets whacked with a 700 x 23c inner tube.
    Last edited by patentcad; 05-07-07 at 03:27 PM.

  5. #5
    Not obese just overweight ratebeer's Avatar
    Join Date
    Dec 2006
    Location
    Sonoma County, CA
    My Bikes
    Trek 7500fx, Cervelo Soloist
    Posts
    2,035
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    d) Not enough information

    It will vary quite a bit for obvious reasons. From nothing to 90 seconds or so.


    The other answer is, ask this guy...

    Joe

    Veho difficilis, ago facilis

  6. #6
    Texas Fight! UT_Dude's Avatar
    Join Date
    Oct 2006
    Location
    Austin, TX
    Posts
    2,023
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Haha, OK . It depends a *lot* on how you're positioned. If you're already using clip-ons, you won't gain as much (though you will still gain, because TT bikes can put you in a more aero position than clip ons.... and also in a position that generates more power).

    It's hard to quantify it without some more details. Were you using clip-ons before? How steep were the climbs? Perhaps an average speed from your TT?
    T E X A S F I G H T !
    http://www.chriscollins.org

  7. #7
    Peloton Dog patentcad's Avatar
    Join Date
    Nov 2005
    Location
    Chester, NY
    My Bikes
    2013 Scott Foil, 2009 Scott Addict R2, 2008 Cervelo P3 TT bike, 2008 Motobecane Fly Ti Hard Tail MTB
    Posts
    56,076
    Mentioned
    26 Post(s)
    Tagged
    1 Thread(s)
    Quote Originally Posted by UT_Dude
    Haha, OK . It depends a *lot* on how you're positioned. If you're already using clip-ons, you won't gain as much (though you will still gain, because TT bikes can put you in a more aero position than clip ons.... and also in a position that generates more power).

    It's hard to quantify it without some more details. Were you using clip-ons before? How steep were the climbs? Perhaps an average speed from your TT?
    Forget the High Point TT, too uphill. I'd like to do more traditional TT's with rolling to flat terrain. No clip on bars now. Just interested in TT bike vs. regular bike with drop bars comparison.

  8. #8
    cmh
    cmh is offline
    Senior Member
    Join Date
    Jul 2005
    Location
    Portland, OR
    Posts
    2,264
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by TheKillerPenguin
    Probably a lot. You've zipps already though, so you're good to go

    I'm trying to finagle a deal on a TT bike, since I've got stage races coming up... I've been Merckxin it and my TT is strong like bull, at 25.7mph. I figure with Aerobars, aero helmet, skinsuit, aero position, and aero wheels I'll be doing some low level flying.
    I thought you had some clip-ons you were using for TTs? If that is the case, that is not Merckxin it; he was before the invention of clip-ons. You have more likely been Lemonding it; he was the first to use clip ons in the TdF in '89.

  9. #9
    Theodore Roosevelt's idol TheKillerPenguin's Avatar
    Join Date
    Sep 2004
    Location
    Vagabond
    My Bikes
    Affirmative
    Posts
    9,002
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    I used aerobars twice last year for stage races, I'd imagine with minimal advantage since I'd only had 2 days to setup and practice my position before each race (if you haven't seen the picture of my position at Owasco, if you need a laugh I'll post it ). But, that's not what I'm referencing.

    My fastest TT ever was done w/o aerobars, and was 10mi @ 25.7mph.
    Last edited by TheKillerPenguin; 05-07-07 at 03:57 PM.
    Masochism is a training adaptation.

  10. #10
    Carpe Diem bdcheung's Avatar
    Join Date
    Sep 2006
    Location
    MABRA
    My Bikes
    2007 CAAD9; 2008 Giant Bowery; 2008 Surly Crosscheck
    Posts
    13,130
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    "When you are chewing the bars at the business end of a 90 mile road race you really dont care what gear you have hanging from your bike so long as it works."
    ΛΧΑ ΔΞ179 - 15% off your first Hammer Nutrition order!

  11. #11
    Little Pony obra3's Avatar
    Join Date
    May 2007
    Location
    Salem, OR
    Posts
    667
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    King Pony OBRA
    Blog
    Cat XXX Whatever Meter- I'll upgrade myself.

  12. #12
    cmh
    cmh is offline
    Senior Member
    Join Date
    Jul 2005
    Location
    Portland, OR
    Posts
    2,264
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by TheKillerPenguin
    I used aerobars twice last year for stage races, I'd imagine with minimal advangate since I'd only had 2 days to setup and practice my position before each race (if you haven't seen the picture of my position at Owasco, if you need a laugh I'll post it ). But, that's not what I'm referencing.

    My fastest TT ever was done w/o aerobars, and was 10mi @ 25.7mph.
    OK -you were definitely Merckxin it. You are going to be damn fast if you ever Zabriskin it .

  13. #13
    Carpe Diem bdcheung's Avatar
    Join Date
    Sep 2006
    Location
    MABRA
    My Bikes
    2007 CAAD9; 2008 Giant Bowery; 2008 Surly Crosscheck
    Posts
    13,130
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    That's a nice, concise summary... and written by the guy who invented my Q-Rings!
    "When you are chewing the bars at the business end of a 90 mile road race you really dont care what gear you have hanging from your bike so long as it works."
    ΛΧΑ ΔΞ179 - 15% off your first Hammer Nutrition order!

  14. #14
    Texas Fight! UT_Dude's Avatar
    Join Date
    Oct 2006
    Location
    Austin, TX
    Posts
    2,023
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Ah... OK, that helps a lot. On a regular TT course, you can pick up something on the order of minutes depending on the length using a TT bike over riding in your drops. The effect is less pronounced if the course goes mostly uphill (AKA, not an out and back...if it goes downhill too, aero is good..).

    Honestly, though, a lot will depend on how you're fitted. Some people opt for more aero, less power (you go for this if you're a weaker rider), some people opt for less aero, more power (the inverse...you get the idea). When i'm on my Cervelo, I go faster mostly because of the aerodynamics, but because of the way we could arrange my saddle position, I actually put out slightly higher wattage too. Summarize? Fit matters.

    Other stuff, specifically having an aero helmet (though really only if you're riding a TT bike position), and a skinsuit can drop quite a bit of drag too.

    If you add it all up, you can drop your time fairly significantly. Think like...3 mins over 20k might not be too rediculous.
    T E X A S F I G H T !
    http://www.chriscollins.org

  15. #15
    pan y agua merlinextraligh's Avatar
    Join Date
    Aug 2005
    Location
    Jacksonville
    My Bikes
    Wilier Zero 7; Merlin Extralight; Co-Motion Robusta; Schwinn Paramount; Motobecane Phantom Cross; Cervelo P2; Motebecane Ti Fly 29er
    Posts
    27,291
    Mentioned
    10 Post(s)
    Tagged
    0 Thread(s)
    flat to rolling terrain, .5 mph to 1 mph, depending on 1) how aero your position alredy is in the drops, 2)how aeroyou set the bike up with tt bars,and 3) how well you produce power in the tt bar position.

    There's a thread in the road cycling forum, where a number of people claim 2 mph, but either there road position just totally sucks, or they're getting a big plecebo effect.

    , I've found the whole deal, trispoke front, disc rear, booties, TT helmet, arendul TT waterbottle, and aerobars is only worth maybe a fraction over 1 mph in my personal expereince. YMMV.

  16. #16
    Texas Fight! UT_Dude's Avatar
    Join Date
    Oct 2006
    Location
    Austin, TX
    Posts
    2,023
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    I don't know about the .5 to 1mph bit. I've ridden TT's in my drops, jersey/shorts, Atmos helmet, then i've ridden TT's on my Cervelo, skinsuit, Garnea Rocket Helmet, deep wheels, etc, and all in all, it's considerably more.
    T E X A S F I G H T !
    http://www.chriscollins.org

  17. #17
    pan y agua merlinextraligh's Avatar
    Join Date
    Aug 2005
    Location
    Jacksonville
    My Bikes
    Wilier Zero 7; Merlin Extralight; Co-Motion Robusta; Schwinn Paramount; Motobecane Phantom Cross; Cervelo P2; Motebecane Ti Fly 29er
    Posts
    27,291
    Mentioned
    10 Post(s)
    Tagged
    0 Thread(s)
    ^^^^
    the .5-1mph was for just the TT bars. Full deal for me is just a little over 1mph, but thats comparing a road bike with Zipp 404's and a decent position in the drops.

  18. #18
    Senior Member zimbo's Avatar
    Join Date
    Feb 2006
    Location
    North Carolina
    Posts
    2,040
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    It's not the TT bike itself that reduces your drag but rather the fact that you're likely able to put your body in a much more aerodynamic position on a TT bike due to frame geometry than you would be able to attain on a road bike.

    To maintain a speed of 27.5mph on flat terrain, I must generate about 30 more watts on my road bike (with 30mm wheels, aero bars, skin suit, and aero helmet) than on my TT bike with Zipp wheels. I'd predict that 25 watts of this is due to body position rather than the aerodynamics of the equipment itself.

    Unfortunately, without acclimating oneself to a more aggressive TT position, it's not uncommon to see a dropoff in power of up to 50 watts on the TT bike compared to the road bike. So it's actually possible for the unacclimated athlete to go slower on the TT bike.

    But I'm talking about a flat TT course and I know Patentcad was asking about a hilly course. Eh, well.

    --Steve
    Last edited by zimbo; 05-09-07 at 01:17 PM.

  19. #19
    Slow'n'Aero DrWJODonnell's Avatar
    Join Date
    Feb 2006
    Location
    Driving the pace in the crosswind
    Posts
    2,599
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Patent, read the articles above. I actualy rode High point with my full TT setup last year and did well, but not outstanding. I WAS blying through the flat section and those rollers though.

    As for the TT bike, it really depends on how well you can adapt to the position, but I am about 2.5-3 mph faster on average on rolling terrain and even moreso on flat terrain. I am also VERY good in the TT position vs. my road position so take that into account. If you are thinkig Somerset TT, go with the TT bike if you have one.

  20. #20
    Peloton Dog patentcad's Avatar
    Join Date
    Nov 2005
    Location
    Chester, NY
    My Bikes
    2013 Scott Foil, 2009 Scott Addict R2, 2008 Cervelo P3 TT bike, 2008 Motobecane Fly Ti Hard Tail MTB
    Posts
    56,076
    Mentioned
    26 Post(s)
    Tagged
    1 Thread(s)
    Thanks for the info boys.

    I really did enjoy the TT immensely. First it focused my training for the better part of two months. Then the race scene was very warm and friendly - moreso than many mass start events in my view. Then in the even itself: virtual zero crash danger, no getting dropped, much closer to running a 5K race for whatever time you can record. You see how you stacked up on a website the next day. Very cool. Very neat way to focus my training. I love climbing, but there are limted uphill TT's, so I'm thinking about picking 4-5 TT's of various types annually. But if that's the focus of much of my riding/training, I'll research TT bikes.

    Which dovetails nicely with Celticfrost's prediction that I would soon acquire more bike schwag.

    Correct.

  21. #21
    pan y agua merlinextraligh's Avatar
    Join Date
    Aug 2005
    Location
    Jacksonville
    My Bikes
    Wilier Zero 7; Merlin Extralight; Co-Motion Robusta; Schwinn Paramount; Motobecane Phantom Cross; Cervelo P2; Motebecane Ti Fly 29er
    Posts
    27,291
    Mentioned
    10 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by DrWJODonnell
    As for the TT bike, it really depends on how well you can adapt to the position, but I am about 2.5-3 mph faster on average on rolling terrain and even moreso on flat terrain. .
    I don't get close to that difference. Guess it shows I don't spend enough time on my TT bike.

  22. #22
    Raising the Abyss celticfrost's Avatar
    Join Date
    Jan 2005
    Location
    TTing on the MUP
    My Bikes
    Expensive ones that I ride slowly
    Posts
    3,776
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    What about headwinds and tailwinds?

    I'm presuming that the more aero into a headwind, the better.

    But alot of TT's are out and back, so at some point that headwind will be a tailwind. How much of a benefit is aero then? Also, is there some point where aero is a DISadvantage with a tailwind? There's probably some other factors to consider as well (surface area of rider, wind speed, etc.).
    "...in Las Vegas where -the electric bills are staggering -the decor hog wild -and the entertainment saccharine -what a golden age -what a time of right and reason -the consumer's king -and unhappiness is treason..."

  23. #23
    Senior Member
    Join Date
    Nov 2006
    Location
    Lake Stevens, WA
    Posts
    1,166
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Bicycling Magazine did an interview with some guys from MiT who studied the aero position for cyclists and if I remember correctly, they ranked a series of items based on wattage saved or something along those lines. Someone who still has the article feel free to correct me (I long-since discarded the magazine), but I think the ranking of most valuable items was something loosely like:

    1) disc wheel
    2) aero bars (these two might have been around)
    3) aero helmet
    4) aero front wheel
    5) bottle on your seat tube vs. the down tube

    Again, someone feel free to correct that list, add to it, etc. I'm going off of memory.

    In terms of seconds saved, I have no real idea. Hopefully the wattage numbers associated with the article would be of some use though.

  24. #24
    Texas Fight! UT_Dude's Avatar
    Join Date
    Oct 2006
    Location
    Austin, TX
    Posts
    2,023
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    I come up with 2-2.5 mph difference riding my TT bike over my road bike. That doesn't include other aero gear. Like I said, though, I put training time in on my TT bike and the saddle position lets me generate more power (25W? that's a guess).
    T E X A S F I G H T !
    http://www.chriscollins.org

  25. #25
    Racing iS my Training Pizza Man's Avatar
    Join Date
    Sep 2005
    Location
    San Francisco
    My Bikes
    07 Bianchi San Jose, 08 Tarmac SL2, 05 Cervelo P3
    Posts
    1,263
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    I've got a TT coming up at the Cascade stage race. It's a new course that climbs 900 feet in 7.5 miles (about 2.3% ave grade), then turns around and comes back down the hill.

    I don't have a TT bike, so I'll be going with clip ons. I did one race with clip ons last year and it was a disaster. (note: practice with the clip ons!) I didn't put them on tight enough and they were nearly vertical within 2 minutes of starting.

    I'm glad the TT is the first stage. That way I can put the bars on before I leave for the race and get in a few practice rides, and not have to worry about putting on the bars between stages.

    I also don't have a disc wheel, but I suppose it would really help on the 2nd half of this race.
    I'll be using my Zipp 303's since they're the most aero wheel I have.

    I will at least have a TT helmet and a skin suit (and my H2O bottle on the seat tube).

    Anything else I can do? Gloves or no gloves? Shoe covers?

    Also, do you guys think that even effort is better, or use more effort on the first half?
    According to this velocity predictor:
    http://w3.iac.net/~curta/bp/velocity/velocity.html

    The difference between 320W and 350W is about 50 seconds on the climb, but only 15 seconds on the descent. Does this sound correct?

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
  •