Weight Weenies

I think about the time trial helmet is the fastest, based on the measurements as a vindtundel tests show.

Some who know of such a test and could link to it.

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Tillquist, I know you know this… it's the one that fits YOU the best. The aero helmet needs to fit your position on the bike and your body profile (primarily back profile for a clean transition from helmet to back).

Decent description of what's important:
http://www.socalttseries.com/p/wind-tunnel-results.html

With all that said, the Kask Bambino has tested really well for a variety of rides. Personally, I love the Rudy Project Wingspan (and the Wingspan 57 is even better, just spotty availability).

Don't have a link to such a test atm.
But here are all available neatly listed with some comments.
http://www.helmets.org/chrono.htm

I used to be professional aerodynamicist. Some of time trial markets on the market today make me laugh. Definitely a case of style over substance.

As others have said, the most important aspect of the helmet is fit. It has to fit your body position when exhausted on a bike. My old colleagues are currently doing a lot of wind tunnel studies with cyclists for the Australian Institute of Sport and they have found the same thing. Different helmets work for different riders.

^ All of the above. Of course, it's pretty unhelpful if you don't have the means/inclination to do testing yourself. From the ERO Sports Aerocamp thread on Slowtwitch, the LG P-09 seemed to be good on just about everyone, and the best on the majority of them.

No way to know what helmet is fastest for you and your position unless you go into a tunnel or do something like the Chung method.

However the Giro A2 tests well on lots of people. Depending on your position, it might be the fastest or it might be in the top 2 or 3 for you. But I have heard that it tests very well on lots of people.

If you are also looking for something to use on a road bike, the Specialized Evade tests very well and is comparable to many TT dedicated helmets. Better venting as well and safer to ride on training rides and races as you will be better able to hear cars and other noises around you.

BTW my comment about 'exhausted' is based on a mate (who does a lot of TT'ing) who says that long tailed helmets are nice to try on in the shop but towards the end of a longer race it takes a lot of effort to keep your head up and keep the tail pointing along your back.

Which is why many helmets are now designed to work well in the heads down position as well.

Helmets that interest me at the moment are the Lazer Wasp and Kask TT helmets. I also think it would be fairly simple to do some flow-visualisation testing on a helmet to give you an idea of how effective it is.

Son used Giro pointed end thing and KASK. Prefers the KASK Bambino because with the Giro the cost of moving the head is too high. On a short TT the Giro may be better. Longer TT - Bambino. Also the KASK Bambino has been used in Crits.

I think the visor is significant, however there can be fogging issues.

Short TT:

KASK Bambino

It's not really my kind of thing but Im curious by nature.
As far as I understand the purpose of such a helmet mainly is to reduce drag.

Does anyone know if there were done experiments with just normal round or egg shaped helmets with smooth surface and a kind of gurney style little spoiler on the back of a shirt?

I use a Limar Chrono 05.

Short tailed helmet that has tested fastest for quite a few people, especially those that tend to look down a lot (and so the tail sticks up in the wind), and faster than its bigger brother, the Speed Demon

Not a popular helmet, but seems to be a similar shape to the crop of newer short tailer helmets available.
Will dig up a link and post it later on.

I've been using the LG P-09 for 1.5 months now and it's fantastic. Comfy, not hot and my times are improved from my previous helmets which included a Bell Javelin and a Giro Selector. I know, many other factors for improved times but man, if that thing doesn't at least feel fast. And what Rush said about being exhausted. It's fun to sit on the trainer and make videos of yourself but very little of that matters until you're at 105% with another 15 minutes to go in a tt.

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