Not fair? Fraysse said “AERODYNAMICS do not matter.” That was a general statement. Boardman’s technological hour record was a combination of excellent positioning (superman) AND excellent frame aerodynamics (Lotus). HPV’s show that low speed aerodynamics also matter. Again, look at the post I replied to. Mike said “how important do you think aerodynamics are when you’re going 25 mph? If you could go the speed of a Stealth bomber, then maybe it does.”
All the vehicles I mentioned show the ridiculousness of that statement, as they are all going several orders of magnitude slower than a stealth bomber. That is just a foolish statement with no real support. Virtually every windtunnel test done in the past 20 years shows that low speed aerodynamics of equipment matters a great deal…
What is normal yaw? I was under the understanding that 5-15 was normal, and <5 and >20 were fairly rare. Zipp recommends comparing wheels at those numbers.
53,832 km. But again, he bettered his own record with improvements in equipment.
Regading Fraysse, he initially said aerodynamics do not matter except at stealth bomber speeds. This sort of “logic” has been debunked enough times in the past that I didn’t really feel compelled to treat such a statement with any sort of seriousness…
For his final record, Rominger was hardly on a “plane jane” bike. http://www.53x12.com/do/show?page=article&id=31
Ferrari’s own words: “The difference in efficiency (aerodynamic and other) was far higher. At 53.04 km/h, Indurain developed 509.5 Watts, while at the same speed Rominger put out 413 Watts—a difference of 23%.”
413 vs. 510 watts. What was that about frame aerodynamics again? The link I posted gives some great firsthand information about the actual equipment Rominger used. It also covers some of the intricacies of track racing (in addition to the no-wind environment) that are worth factoring in to the discussion. The lack of crosswinds on the track are definitely a factor in why an aeroframe does not perform better in a velodrome, saving only ~5.7 watts (best case) @ 45kph according to Tour. This stands in stark contrast to the windtunnel tests which factor in the 5-10* yaw angle commonly seen on the road.
5-10* of yaw is normal. 15* is on the high side, but certainly present on a course like IMH, hence it’s value to many triathletes. But 15* is definitely on the high side unless you live somewhere that is very open with high winds (i.e. one of the plains’ states or Hawaii or similar).
At 20mph, you’d need a ~5.3mph direct crosswind AT GROUND LEVEL (that’s the key, since wind speeds are rarely measured ~1m off the ground, usually they are measured much, much higher) to get 15* of yaw. That’s a pretty stiff wind, and to get it perfectly perpendicular to the path of your bike is going to be even more rare.
How can frame aerodynamics mean “virtually nothing,” and be “actually detrimental” at the same speeds? Also, I think your closing statement is way too absolute. Training is very very important but positioning, pacing, and tactics do play a role. Maybe you should consider the power available to stealth bombers as well as their speed.
so splitting the difference of 5 and 10 percent yields 7.5 percent reduction due to aero tubes. If the frameset + wheels = 20% and the wheels and bike each contribute 10% of total drag, a round tube bike would cost you .03lbs of drag. For the calculation assume that the rider has a good position with 3.8lbs of drag at 26mph for the bike + rider (aero framed bike).
Josh at Zipp has said .1lbs of drag = 6 watts, so .03lbs-force would equal 2 watts. 2 watts? Is this it or does my math have a major malfunction?
You have a major math malfunction. Here are some representative nominal values which hopefully will reboot your processor:
drag of rider + round-tube bicycle at 30 mph and 0 deg yaw = 6.0 lbs
drag of rider + aero-tubed bicycle under same conditions = 5.4 lbs
Difference in drag = 0.6 lbs, or 10%
Drag of same round-tube frameset plus wheels = 1.68 lbs
Drag of some aero-tubed frameset plus wheels = 1.08 lbs (20% of total)
Drag of pair of typical aero wheels = 0.6 lbs
Drag of round-tubed frameset (by difference) = approx. 1.08 lbs
Drag of aero-tubed frameset (by difference) = approx. 0.48 lbs
To convert to watts or speed, you can assume that 0.1 lbs of drag = 5 W = 0.5 s/km at typical racing speeds.
53,832 km. But again, he bettered his own record with improvements in equipment.
By a little more than 2 km, IIRC.
For his final record, Rominger was hardly on a “plane jane” bike. http://www.53x12.com/do/show?page=article&id=31
Ferrari’s own words: “The difference in efficiency (aerodynamic and other) was far higher. At 53.04 km/h, Indurain developed 509.5 Watts, while at the same speed Rominger put out 413 Watts—a difference of 23%.”
413 vs. 510 watts. What was that about frame aerodynamics again?
That’s hardly a fair comparison or conclusion, given that Indurain was significantly taller and heavier than Rominger. You’re right, though: it’s a mistake to think that Rominger didn’t benefit from use of an aerodynamically-designed frame, even if it was more conventional looking that most.
He put it at 55 and change. I have a framed picture of his ride on my office wall. Round tube Colnago with dual discs - 700c rear, 650c front! And a big ol’ hump in his back. Oh yeah, standard road/track position, probably no more than 74 degrees ST. When he got off his bike, he wasn’t even breathing hard. He stated (as I recall) that he left too much in the tank.
Of course, I also remember the rumours floating around after that about how he was epo’d to his eyeballs and his VO2max had been measured at >110 mls/kg.
He put it at 55 and change. I have a framed picture of his ride on my office wall. Round tube Colnago
Sorry, but the bike had aero-profiled tubes, not round ones. This fact is clearly evident in the British magazine coverage of his hour record (thank you Bob Tobin for photocopying and sending me ~100 pages of this and similar articles way back when).
That’s true, but we both know that height/weight discrepancies (which are covered in the article on 53x12) usually play out in favor of the bigger rider when it comes to time-trial riding, since a rider that is twice as heavy is not usually twice as “large” (to use a rather general term). Rominger was substantially more aerodynamic (although Ferrari does admit that he had a superior position to Indurain) than the difference in morphology should have accounted for. Speaking very loosely, the rider who can generate more power should be able to go faster in (relatively) flat race, even if he is much heavier, even on the velodrome where inertial forces while cornering are a factor.
I certainly did not mean to imply that the difference of 100 watts or so (or 23%) was due strictly to the frame. It was more just an observation on aerodynamics in general, of which the frame was obviously (looking at the differences in Rominger’s own attempts) a factor.
On a sidenote, it’s nice to be on the same side as you for once today. I actually have to use my brain to reply to you when we disagree, which can be quite taxing…
