I don't recall what Craig was wearing but Chrissie Wellington was wearing a regular bike helmet. Does that mean that aero helmets are hype? No, they are not hype.

There is a great article on that can explain this much better than I can, I quote:

" Cote: Most people don't realize that a nonaero helmet creates four times the drag of a nonaero wheelset. So you can spend two thousand dollars on a wheelset, or spend two hundred on a helmet and be faster. How you put your race number on matters more than having an aero wheel; today, we glued on our numbers to get them to fit flatter. Then there's water bottle placement: On a round-tubed frame, having a bottle on your seat tube is more aerodynamic than not having one at all, and it's much more aero than putting it on the down tube. And wearing gloves in a time trial will slow you down more than using a nonaero front wheel. "

The rest of the article can be found here:

http://www.bicycling.com/article/1,6610,s1-3-12-14995-1,00.html

We get so hung up on the gear that sometimes we fail to realize the "engine" is everything and the gear just compliments it. These are elite athletes and they choose to not wear an aero helmet. The engine is still that of an elite athlete.

Some say aero helmets are hotter than regular helmets because they don't have vents. Perhaps these two get too hot and opt for a less aero but cooler head. Personally, I have an LG Chrono and I can't tell the difference between it and my road helmet.

I got an aero helmet last year as a birthday present and it helps to the tune of roughly 0.2 mph faster average over 20 miles (I rode the same course one week apart with/without the helmet, not too scientific but it's all I have. The science says it's faster as well, otherwise, the TTs in the Tour wouldn't look the way they do). Ridden in 85 degree temps over a 40K race they are not too hot. Finally, I like them because, like most tri addicts, I like the psychological boost I get from feeling my equipment is not limiting my personal potential. As to the Ironman question, it's 112 freaking miles, man! Not a time trial by any stretch. Personal comfort/training style becomes paramount. Although perhaps Alexander is now thinking if he had worn one, could he have taken the race? We'll see what's on his head next race. Good luck and speedy racing.

How do they measure the claim that an aero helmet will save you 30-60 per hour? I haven't read any of they articles but I'm guessing they do it in a wind tunnel? How often do you race in conditions where the wind is hitting you head on the entire time? Wouldn't a crosswind affect an aero helmet more? Maybe not, but is a good question. Also, are you in your aero position the entire time? Everytime you put your head down (and the tail of your helmet comes up) you increase your frontal area, increasing drag....

I don't have an aero helmet and I'm bored, so I'm playing devil's advocate. :)

:)

someone should invent an aero helmet that floats on your head like one of those weebles we all played with when we were kids then it would sit level no matter how we put our head

The drag the aero helmet saves isnt really in the extended tail- its the lack of vents. All those vents on a normal helmet give air LOTS of room to move around and lots of little walls for it to hit- at ANY angle. The long flaired tail simply helps shape the air in the direction you are traveling for the entire race- forward.

You can tape or heat shrink a normal roadie helmet, like I do, and get 85% of the aero helmet benefit by eliminating all those spaces and walls. It makes ytour helmet look shiny. And if you dont do a good job taping it, it looks like crap. I am looking at an aero helmet just save the time it takes to do a quality taping job.

I think I saw the same article GGehrke. The person listed different items based on aero improvement for the least cost. There were many free things that would give a second or two advantage over 40k (shaving legs, taping down shoelaces, removing a water bottle). Deep dish wheelsets and aerohelmets were shown to improve potential performance much more, but cost much more as well.

It's hard to say whether wheels or helmet will actually improve performance the most because there are so many variables involved. But the general conclusion I've gleaned from many different articles is that the benefit is close to equal. Since an aero helmet costs far less I think it makes sense to upgrade that first.

I agree, but actually for a different reason. It's been shown in these types of applications that frontal area is actually less significant than reducing the parasitic drag behind a moving body. That is, it's more effective to try to get the rear tapered so the air can return to laminar flow than it would be to try to minimize frontal area. That's not to say some giant object with a long tail will be more aerodynamic than a torpedo type object that is slender all the way along, but if you're going to put effort into improving the aerodynamics of something like a helmet, adding a fairing is the best way to go. Without it, the air forms a pocket of low pressure behind you that literally pulls you back. (This is the same pocket of air that allows a wheelsucker to suck). The tail on an aero helmet allows the air to become laminar more quickly. This is also where the vents come in - not so much that they form little forward facing parachutes, but that they create turbulence around the helmet which disrupts the laminar flow around the helmet and allows that pocket of low pressure to form in the area directly behind the head. A standard helmet has air going every which way around and through it, creating a terribly dirty bit of air behind the rider's head. Dirty air=low pressure and low pressure sucks.

Again, I'm not an aero engineer, so I'm not going to try to talk intelligently about Reynolds Numbers or anything like that, but the benefit of an aero helmet is that it essentially acts as a rear fairing - the only legal type of fairing in cycling - and reduces parasitic drag. This is also why it's so important to have one that fits well with your neck and back shape to get the best advantage possible.

-Grant-

And I thought peaking just shy of 50mph on my bike was a rush. How much fun must THAT be!

-Grant-

Try one. Here is what I did. I rode 5 km TT without and then 5km TT with (I know unscientific).
Saved around 30secs. More importantly I could notice a decrease in sound wearing the aero one. Sound is energy wasted. Therefore a quiter helmet means you are wasting less energy.

Also, you aren't truly a tri-geek until you can sport a "sperm" helmet and think you look cool!

We need a photo of the swim with both helmet styles to finish off this discussion! :D

Someone out there has both types of helmets, right?

only with the reg helmet ;)

The only reason I knew the name was because myself and a group of college buddies tried to build one as a senior engineering project. However, we were nowhere near the 81 mph record. However, it is now apparent we might have beat the record if we had worn an aerohelmet.

Let's put it this way, an Aero helmet is more drag efficient than a conventional helmet, So, if you can get one at a reasonable price then I would get it.

i'm 13 and doing my first iron distance in 2 weeks i'm going to wear my buddies spiuk feels great and looks cool!!!