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Talk to me about aero(21 posts)

Talk to me about aeroFasterfaster
Oct 25, 2001 8:46 AM
The tri riders are so into the aero thing, and I don't understand why it hasn't reached road bikes to the same degree.
I know that road riders don't want to use aerobars in a pack, but what about things like aero seatposts, and rear wheels tucked into the seat tube, and aero forks, and stuff.
Look, I'm told that aero wheels are more important than light weight wheels in nearly all cases. Are wheels all that matters? If not, why are the tri riders so into aero, while roadies pretty much ignore it?
Think of it as a Dragster vs a Sports carDave Hickey
Oct 25, 2001 9:02 AM
They have seperate uses but they are both fast. The Tri guys are going shorter distances and ride in more of a straight line. Look at the time-trial bikes, they look much closer to a tri-bike.
SimpleBipedZed
Oct 25, 2001 9:05 AM
Most bike sections in a triathalon don't allow drafting, it is essentially an individual time trial where aerodynamics are extremely important.

Road racing is all about riding in a pack or group of riders to gain the benefits of drafting where aero equipment is not much of a factor. Road bike equipment trickles down from the racing scene and is not as concerned with aerodynamics.

If you never ride with a group then you may wonder, but any kind of group riding involves drafting and as such, aerodynamics aren't as important.
hanging with group vitalDog
Oct 25, 2001 9:12 AM
As you note, with road racing or group riding you'll never be dropped because of aerodynamics; however, you might easily be dropped because of weight (or more precisely, power to weight ratio).

Following another rider at 25 mph, aero is not very important.

Riding alone in 25mph air, aero is very important.

So, if you expect to lead a road race, get some aero stuff. If you are suffering to stay with the group on hill, get light.

Of course, sometimes you can have both, such as with HED Alps carbon wheels, or Zipp 303's or even 404's.

Doug
Horses for coursesJS
Oct 25, 2001 9:08 AM
Alot of road riders are into aero stuff.....on their TT bikes. For Road racing, the only thing that really provides a measurable difference is a deep section (50mm or more) aero wheel, the other things you mention don't really do much (aero seatpost) or compromise handling and are impractical. In a TT where every second counts it may be worthwhile to make a bike as slippery as possible but for road racing it isn't really necessary.
best aero deviceSpikedawg007
Oct 25, 2001 9:11 AM
most important thing you can do to gain speed is to ride in the most minimal position you can. pros wouldn't be pro if they couldn't sustain aero riding positions for long. All the other stuff (except for wheels) will get you incremental gains, but the cheapest and most noticable gain comes from your technique, not equipment.
A great aero tip.Pack Meat
Oct 25, 2001 9:29 AM
Because of the longer events in road racing you have to throw comfort into the equation. Riding in an aero tuck for 130 miles would not be fun. You also have to consider handling in sprint situations.

The best areo tip I've ever heard is based on the study of really fast animals. If you look at grey hounds and cheetahs closely you will notice that the trailing edge of their legs has a tuft of hair leading vertically done the leg. This assists the legs movement through the air because the tuft of hair allows the air to smoothly leave the leg. It, in effect, changes the shpe of the leg from roundish to a aero tear drop shape. This reduces the eddy currents that a round shape would create and creates a more laminer flow. So if you shave your legs you should leave a vertical strip of hair along the backs of your legs to improve air flow around your legs.

Chew on that for a while.
PM
You must be kidding...TJeanloz
Oct 25, 2001 9:54 AM
As a student of physics, I'll concur that such a scenario probably does reduce pressure drag.

As a student of fashion and style, this is ridiculous. Any aero benefit is far outweighed by the emotional ridicule that you would be forced to suffer at the hands of your riding group. And I encourage anybody who sees another rider with this shaving pattern to openly make fun of them.

If you're Greg Lemond, and it's 1989, and every 1/100th of a second counts, MAYBE. If you're a jack@ss cat 3 trying to win the local TT, you still look like a jack@ss.
So you admit that it will make you more aero?Pack Meat
Oct 25, 2001 11:02 AM
Keep in mind that this is just one thing to put into your aeroarsonal. I probably wouldn't shave like that unless I was also including the aero advantage of the mullet.
Yes,TJeanloz
Oct 25, 2001 11:15 AM
I do think it would make you more aero. But the aero benifit is tiny, perhaps not even measurable. And the ridicule will certainly be measurable.
The greatest advancements are often met with ridicule....Pack Meat
Oct 25, 2001 11:56 AM
from the naysayers and the unimaginative. Besides ridicule is highly subjective. You can't go through your life worried about what people will think. I don't think that shaving the stripe on the back of your leg will be the next popular advancement. But if somebody does that and breaks the hour record people you can bet people will shave the stripe. The stripe advantage is quantifiable.
yes, and silly things are often met with ridicule, tooDog
Oct 25, 2001 12:14 PM
I'd bet a big pile of money that hair on the back of your legs will not make anyone measurably faster. Besides, if you are getting that desparate for time, I'd assume you have done everything else possible, like having your ears removed.

Another thing, who's to say what the "purpose" of the hair on the backs of the animals' legs is. It may be to make them quieter, to sneak up on others??? Pure speculation.

I thought this whole thread was really a joke, anyway. "You was serious 'bout that?"

Doug
You may be on to something.Pack Meat
Oct 25, 2001 12:36 PM
First of all the animal hair only raised the question. Of course it's speculation, but so is the observation that cheetahs use their tails to help them manuver at high speeds. That's why you test the hypothesis to see if it holds water.

Now then getting to your ear idea. I think that cutting your ears off is extreme. But if you could have them surgically turned around they probably wouldn't catch as much air. After all most fast animals can tuck their ears down when they are moving fast.

Finally if you press your tongue into your cheek....
so, let's shave a cheetahDog
Oct 25, 2001 12:57 PM
let's shave one and see if it slows down :-)
shave one side to see if it can hold a line! :o) -NMTig
Oct 25, 2001 1:07 PM
face hurts from laughing. you guys are killing me. nmJs Haiku Shop
Oct 25, 2001 1:10 PM
more funny stuff.Woof the dog
Oct 27, 2001 3:00 AM
To improve airdynamics of a steel round tubing road bike maybe you could tape some doghair on your frame. Or even better, cheetah hair!!!! I am thinking seatstays will benefit the most, as well as seat tube. Maybe cut off cheetah's tail and stick it to the back of your helmet?

Another good idea: instead of removing ears surgically or using tape to "tape" them back, just use some superglue. Its amazing how well this stuff bonds skin to skin. You could also superglue your dick to the top tube to make you stay down low and aero.

Peace

Woof the superglue dog.
I doubt a "hair-foil" is measurable on a humanTig
Oct 25, 2001 1:05 PM
Don't take this personal. It's just observation.
First, you'd need thick, long hair to complete laminar trailing edge air flow. With the exception of a few grizzly guys I know, most couldn't grow the kind of hair a cheetah has back there. A tiny mohawk strip of fuzzy hair on a round human calf just won't help. The animals mentioned have thinner legs to combine with the hair-foil. The fastest pro races average in the upper 20 MPH, and even a thin-legged rider wouldn't benefit from the fred-hawk hair. It sounds silly, so maybe the silly factor increases speed!
Riiiiiight....grzy
Oct 25, 2001 6:01 PM
Actually you may have a valid phenomenon, but your reasoning is incorrect. The hair would trip the flow to the turbulent regiem earlier to reduce the drag. Kind of nature's vortex generator as it were. To say that this is why the hair is there is making a huge assumption. Ultimately a cheetah is a sprinter and has very limited ability in terms of endurance. Given that the cat is probably operating anerobicaly, endurance issues and minute aero advantages are but a small part of the picture - to be sure aerodynamics is important no matter how long or short the race is. Realiz also that a cat travelling at a high rate of speed has to have legs travelling even faster - the dimensionless ratio that people refer to is the Reynolds number - several of the factors are the size of the object (length) and speed. We're pretty damn slow when on considers the size of our legs/arms and the fact that we aren't travelling that fast in comparison.

Now to call this the best aero tip you've ever heard is really pushing it. How do YOU use it?
re: it's illegalcyclopathic
Oct 25, 2001 10:00 AM
at least things which impair handling (aerobars, bullhorn bars, Tri BB placing).

Little things do get down to road races (wheels, forks, seatpost, frames, helmets) but as Dog said they're usually non-factor. Races are not won on flats they either won on climbs or in sprints both benefit from stiff/light for better power transfer and power to weight.

this of cause excludes TT or ultra marathon events but those don't allow drafting
There was link recently about Road/TT differences..Dutchy
Oct 25, 2001 5:28 PM
Someone posted a link recently about the difference between a "road" bike and a "TT" bike.
It basically stated that the geometry was different for a TT to allow the rider to sit in such
a tight position for long periods. The seat was further forward to stop ones legs hitting their
tummies while in such a low position. Allowing for easier breathing when low.
It was a great article but sorry I don't have the link.

CHEERS.