Aerodynamics of the $10,000 triathlon bike.
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tri-ac posted 38 weeks ago.
i think because the rider shape outweighs the bike shape, the ROI is not there for uber-tweaking the bike itself
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TriSooner posted 38 weeks ago.
jwillia852 wrote:
The front brake levers, the front brake itself, the height, the wheelbase, the seat.
USAT rules 5.11 Bike Specs parts a - b have rather clear rules about dimensions. But interestingly, you could ditch the front brake all together. So if you are really hardcore about aero, lose a brake. USAT 5.11 Bicycle Specifications, (j) There must be one working brake on each of the two wheels.
jwillia852 wrote:
Are there any rules to adding an inconspicuous airfoil to create upforce?
Yes. USAT 5.11 Bicycle Specifications (e) There must be no protective shield, fairing, or other device on any part of the bicycle (including frame, wheels, handlebars, chain wheel, and accessories) which has the effect of reducing resistance.
You can get the most “aero” frame, integrate all of the cables, fret of 23mm or 25mm tires, debate the effects of a crosswind on a disc wheel vs. trispoke, wear the skinniest of skin suits, and don an aero helmet, but you – your body mass – are the largest frontal area offering wind resistance. Look at the difference below in the body mass moving through the wind vs. the teeny tiny frame (and acknowledgedly the turbulence created by the wheels, too). Moving a 150lb +/- body of mass through the wind will obviously create more drag than a 17lb +/- frame. So, I assert that positioning is more important than frame.
All discussions about aero bikes are fun and valid considerations, but unless you can maintain an aero position, you've negated all (of the comparatively small) benefits from the frame.
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TriSooner posted 38 weeks ago.
tri-ac wrote:
i think because the rider shape outweighs the bike shape, the ROI is not there for uber-tweaking the bike itself
Gospel. But we do it anyways . . . wink wink . . . because it will make us go faster (AKA, buying speed). That reminds me: I need to start marketing aero running shoes.
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jhudalla posted 38 weeks ago.
TriSooner wrote:
That reminds me: I need to start marketing aero running shoes.
Ha ha! Proven to reduce your marathon times by .025% Available in faster colors!
Weary is the path that does not challenge.
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NotAsFast posted 38 weeks ago.
I just bought red ones. That should make me faster.......
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jwillia852 posted 38 weeks ago.
TriSooner wrote:
All discussions about aero bikes are fun and valid considerations, but unless you can maintain an aero position, you've negated all (of the comparatively small) benefits from the frame.
I totally understand the body mass factor, but if all else equal, it was more curiousity about the bike and the extreme measures that some go through to gain the competitive advantage. Lord knows I feel like a mack truck on my bike at times, lol
As for the rules... I've certainly never read them, but all good stuff to know before I go all F1 on my Madone. The cool thing about autoracing is how creative people will get to push the legal limits, and find every loophole... sometimes prompting quick rule changes!
Jeff
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jhudalla posted 38 weeks ago.
Yes, but unlike autoracing, bicycle speeds cannot reach upwards of 200mph. Since wind resistance is x^2 any advantage on a car at that speed will be huge... but at 20-25mph the same change would probly not make any difference at all.
Weary is the path that does not challenge.
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xc800runner posted 38 weeks ago.
TriSooner wrote:
USAT 5.11 Bicycle Specifications, (j) There must be one working brake on each of the two wheels.
I'm not a lawyer, but I'm pretty sure "each" implies you are required to have a brake on the front and rear wheels. Though you need only one per wheel... You could argue that on a fixie, your legs act as a working brake on the rear, but you'll always be required to have a front stopper.
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rhane posted 38 weeks ago.
Even if you could somehow come up with a bike with an airfoil on the front to completely shield the entire bike and rider from the wind that would be legal, I wouldn't want it. It's the same reason I don't want a belly putter - if I can't put with a normal putter it's my own fault. If we want to completely reduce drag and race in a perfect vacuum, then take the Ironman inside to a vacuum and put respirators on the faces of the athletes. See who can cover the entire distance the quickest, then put them on the treadmill. Part of the sport, to me, is dealing with the conditions. It makes is more exciting, it forces athletes to use reasoning and intelligence in the spur of the moment to ultimately dictate who wins.
I'm sure you could invent a bike that rides 5 inches off the ground where the "rider" lies flat and is covered in a carbon vacuum bag with an airfoil an 5 hours worth of air coupled with a lightweight computer monitoring system that actually steers the bike for you. At that point, you may as well hook up athletes to "the matrix" and have them see who is the fastest in their minds.
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jwillia852 posted 38 weeks ago.
jhudalla wrote:
Yes, but unlike autoracing, bicycle speeds cannot reach upwards of 200mph. Since wind resistance is x^2 any advantage on a car at that speed will be huge... but at 20-25mph the same change would probly not make any difference at all.
Sure there is no comparing the two on the physical aero. Like I said originally...
I wrote:
"it is understood that aero effects are greater with an increase in speed, but even at triathlon speeds, especially112 miles of 20xmph at your local IM, attention to aerodynamics has proven to shed substantial time"
Like racing, however, people do a lot in triathlon to gain every advantage. I have seen the tests, but I would be willing to bet that an aero helmet has little effect on 90% of the people who wear one, but yet they still do. Which is awesome to me. I am always interested to hear from the most competitive group of people on the planet, what they think could realistically be done to shave some time.
If it's good the way it is, then thats cool too. :-)
Jeff
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xc800runner posted 38 weeks ago.
jwillia852 wrote:
The front brake levers, the front brake itself, the height, the wheelbase, the seat. Are there any rules to adding an inconspicuous airfoil to create upforce? In the age of Carbon Fiber, is the traditional design of a bike even still necessary? How about hydraulics? I know the professional designers have not exhausted all options of aero, and that the next big idea to shave a minute is still out there, but where do you see inefficiencies? What would you do different?
This brings to mind Boardman's Lotus Sport:
Arguably the fastest bike ever built (plus it's still got the hour record). It was designed for the track, in a time when the UCI hadn't yet banned exotic frames, and was designed/built by the good boys at Lotus (the car maker) in 1992. This design, and anything similar is still allowed in USAT racing, but not UCI bike races, which is the main reason why all the major bike manufacturers no longer build frames that don't conform (at least somewhat) to the "double diamond" design. Trek had their y-foil in the late 1990's into 2000 or 2001 which they discontinued due to UCI changes and a lack of market. As the triathlon market grows, you may see larger bike manufacturers designing non-uci compliant frames, but I would expect these exotic shapes will remain the realm of smaller fabricators like Ceepo (whose tubes are too thin to meet UCI 3:1 standards) and CAT.
I doubt placing airfoils on the bike will create any discernable lift without being too large to fit within a lane on the road (though it would be nice to have a bike with wings so large you get your own rack in transition). I'm pretty sure aerobar designers would be playing up this fact if they designed a bar that created lift. But the fact is, any lift on the front of the bike would be added weight on the rear unless you decrease force at the center of mass. So you would need to add airfoils to the front and rear of the bike to create the desired effect (but again at even 30 mph, this won't cause that great a difference).
Also, one of the designers of the CD0.1 posted over on ST regarding where his research will do forward in the aero field. Pretty interesting read.
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Nobody posted 38 weeks ago.
Great site for more info on Bike Aero:
http://www.efluids.com/efluids/pages/bicycle.htm
Greatness is only achieved by those who perpetually raise the expectations of themselves to the point where it ruins their life.
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Anton posted 38 weeks ago.
Is this what you guys are talking about?
http://www.zzipper.com/
There is a reason they don't allow recumbants or other bikes with farings and all sorts of other gee-gaws in road races, triathlons and RAAM. With a well conditioned rider they are too fast!
http://www.youtube.com/watch?v=jUgXtZFdUcs&feature=related
58 mph for one hour...
"If e wishes to sweem in dangerous waters, oo are we to deny im?
-Chef Skinner
http://antonspath.blogspot.com
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Triguy98 posted 38 weeks ago.
Those uber expensive bikes, especially the Italian ones, arent even the fastest of the tri bikes. The reason, keeping with quirky European design standards, if form over function. It has to LOOK cool, first and foremost. Speed and aerodynamics are secondary.
Life is short. Play hard and get dirty doing it.
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jnrice posted 38 weeks ago.
jhudalla wrote:
TriSooner wrote:That reminds me: I need to start marketing aero running shoes.Ha ha! Proven to reduce your marathon times by .025% Available in faster colors!
oh! are my sale rack blue and white Adidas the reason I didn't make my time goal in my marathon!? curses on you Adidas! I will buy faster shoes and win every race! Oh, and good morning all, how's your coffee?
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FireRep posted 37 weeks ago.
I took a look at reducing weight to make me faster. I went to the LBS and talked to them about lighter pedals. For another $120 I could shave about an ounce off my bike. Over the last six months, I have lost 22.5 lbs. Thats about $486,000 worth of fat!
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212 days
triharder.co.za posted 10 weeks ago.
rhane wrote:
Even if you could somehow come up with a bike with an airfoil on the front to completely shield the entire bike and rider from the wind that would be legal, I wouldn't want it. It's the same reason I don't want a belly putter - if I can't put with a normal putter it's my own fault. If we want to completely reduce drag and race in a perfect vacuum, then take the Ironman inside to a vacuum and put respirators on the faces of the athletes. See who can cover the entire distance the quickest, then put them on the treadmill. Part of the sport, to me, is dealing with the conditions. It makes is more exciting, it forces athletes to use reasoning and intelligence in the spur of the moment to ultimately dictate who wins.I'm sure you could invent a bike that rides 5 inches off the ground where the "rider" lies flat and is covered in a carbon vacuum bag with an airfoil an 5 hours worth of air coupled with a lightweight computer monitoring system that actually steers the bike for you. At that point, you may as well hook up athletes to "the matrix" and have them see who is the fastest in their minds.
Hahaha hilarious!! Thank you! I wonder who would win in the matrix system? Probably some IT wizz kid or something
And as far as aerodynamic shoes go, they actually put Maurice Green and Michael Johnson in a Wind Tunnel at their peak (100m and 400m respectively, for those that don't know) and tested shoes with a cover over the laces. Didn't do much for Green I don't think but they shaved a good second or two of Johnson's time! NICE!
I'm bringing this thread up from the dead coz I was researching the deal on UCI legal. Never really paid attention to that but recently read Slowtwitch's preview for the 2010 bike models and was wondering if there were any bikes just "Tri Legal"!
As usual this forum makes me laugh. Its great to have like-minded Tri "geeks" to chat with. My Better Half gets an earful and just rolls her eyes haha
I come from a history of auto racing - I have worked on Indy cars, pro cups and a myriad of other types of professionally sanctioned cars where millimeters are considered in altering the drag coefficient and making the air flow over or under at a rate of least resistance. Last week, I was home working on a car with my dad and his engineer friend, and we got talking about the sport of triathlon and about aero benefits etc. I have a Trek Madone roadie and as he looked at it he said “hasn’t changed much in 30 years” (referring to the aero) – got me thinking a lot about the physics aspect of these bikes.
In racing, we pick our aero package based on track speed, and it is understood that aero effects are greater with an increase in speed, but even at triathlon speeds, especially112 miles of 20xmph at your local IM, attention to aerodynamics has proven to shed substantial time. Even the minimal affect of a helmet, wheels or dimpled shirt is considered. I have concluded that Triathlon Aerodynamics has to be a multimillion dollar industry in itself.
Back to point, when you look at the most expensive bikes (some of which are posted regularly by members here) and really consider the way air flows over the rider and around the bike, you can’t help but notice that there are still turbulent leading edges and inefficiencies that could arguably add measurable time over the course of 112miles.
The front brake levers, the front brake itself, the height, the wheelbase, the seat. Are there any rules to adding an inconspicuous airfoil to create upforce? In the age of Carbon Fiber, is the traditional design of a bike even still necessary? How about hydraulics? I know the professional designers have not exhausted all options of aero, and that the next big idea to shave a minute is still out there, but where do you see inefficiencies? What would you do different?
Disclaimer** Aerodynamics is not a consideration when I get on my bike, but finishing is. I do know that for some it can be the difference of a championship, gold medal, or PR.
Jeff