Is an aero helmet worth it?

love2ride

I didn't mean i looked or turned my head sideways in time trials. But if you do on a training ride or a triathlon you feel the difference.

Tspec

ugo.santalucia wrote:

Airwave wrote:

Just to be different then,try burying your head in a bucket sand to see if your faster or slower :roll:

Don't get me wrong... I still don't believe a word you guys say. Don't believe Contador would have been 50 seconds slower had he worn a conventional helmet in Annecy... don't believe Pozzato would have caught Boonen had he had one at the Paris Roubaix... but then again, I am skeptic by nature. Obviously I don't have fancy maths that take into account a restricted and purposely selected number of factors to support any of my statements, which are therefore of little use.

I guess the moral is: if you want to get the quickest possible time you need one, but don't expect miracles... 50 seconds in a 25 miles TT is a miracle

What are you basing this on?

scherrit

Getting back to helmets....

I wear a Kask which I love, find it very very much more comfortable than the Bell or Giro which I tried.

As far as I know, this is the next most sensible place to spend your hard-earned dosh after a set of aero bars, and before getting deep section wheels.
YMMV,
Scherrit.

Escargot

ugo.santalucia wrote:

Airwave wrote:

Just to be different then,try burying your head in a bucket sand to see if your faster or slower :roll:

Don't get me wrong... I still don't believe a word you guys say. Don't believe Contador would have been 50 seconds slower had he worn a conventional helmet in Annecy... don't believe Pozzato would have caught Boonen had he had one at the Paris Roubaix... but then again, I am skeptic by nature. Obviously I don't have fancy maths that take into account a restricted and purposely selected number of factors to support any of my statements, which are therefore of little use.

I guess the moral is: if you want to get the quickest possible time you need one, but don't expect miracles... 50 seconds in a 25 miles TT is a miracle

Unfortunately you get a lot of BS with any kind of hobby/sport/etc. Take £200/m speaker cables for example :?

Cycling is no different as there is a lot of BS with cycling too. However having studied this kind of thing I can assure you that an aero helmet will definitely have *some* beneficial effect. With wind/air resistance the amount of resistance experienced is relative to your speed squared so the faster you go the resistance rises exponentially. How the pros still manage to average 35+ mph is beyond me as the wind resistance must be power sapping to the extreme :shock:

But I digress. It's pretty difficult with cycling as your body represents such a horribly un-aerodynamic shape that combatting drag is a nightmare. However one thing is for sure, a conventional helmet will be a lot worse than an aero one that is designed to cut through the air (so to speak). Although your head is not something that represents the largest frontal area, the air still has to flow over it so is important that positioning and shape is optimised (kind of like wearing a cap when swimming). For the rest of the body a skinsuit will help the air flow more efficiently. Other than that I'm not sure there's much else to do other than to get yourself in the most aero position possible.

As I'm not an aerodynamicist then I don't know exact details but have read that an aero helmet is as effective as aero wheels (both of which contribute up to 20% of total drag each).

So not really miracles but sensible engineering.

Escargot

Just to add, the images highlighting flow around different shapes is highlighted on this page:

http://en.wikipedia.org/wiki/Drag_(physics)

Aero helmets are very much like wing sections whereas conventional helmets are more spherical. The images are a bit extreme but not a million miles away.

I'm not sure if this is a good example but the 1989 final TT between LeMond and Fignon was a classic where LeMond wore an aero helmet and Fignon wore nothing at all. If you look the vid up on youtube you can see that LeMond is in an aero position whereas Fignon is all over the place. How much is attributable to the helmet is anyones guess and respective power outputs are also unknown but LeMond won by about 50 seconds. Given both were pretty equal then it is very probable that the difference was down to aerodynamics

ex-pat scot

In priority order for going faster:

- get your position right on the bike. Flat back. flattish arms. And be able to maintain that position for the whole of the TT
- skinsuit (long sleeve is faster than short sleeve)
- deep section front wheel

These things make the most difference (and no, I'm not quantifying them).

Then stuff that is more marginal (in rough order):
- aero helmet (mine is a 1994 MDT carbon shell)
- overshoes
- deep section rear / disc rear
- shaving
- aero components (frames with fairings, solid chainrings, flat profile bars & seatposts)

That's my anecdotal experience.

To be quite honest, I #could# do a set of exhaustive tests of kit combinations using a straight roll test on my local hill. But really, life is too short.

My general approach would be to get a decent comfy set of aerobars, tight skinsuit, aero helmet and deep section front wheel.
I would experiment (using an Ergo stem if necessary) with position, to try and find as flat a position as I can maintain.

And then I'd spend my time and focus on improving the engine...

Pokerface

ugo.santalucia wrote:

That means that if Pozzato was allowed to wear one at the Paris-Roubaix, he would have caught up Tom Boonen who was 10 seconds ahead of him at about 12 Km to the finish, considering that advantage stayed constant until pretty much the end.

I don't believe it... maths rarely apply to road cycling

You are correct in saying the "maths rarely apply to road cycling". But we're talking about TTing, where there are more constants to deal with.

(For the record - ANY rider CAN wear a TT helmet in a road race if they choose to. But they aren't practical, which is why they don't.)

The time savings an aero helmet provide come from keeping the head in a fixed position for as long a period as possible - and that fixed position has to be the optimal aero position that the helmet was designed for.

If you wear an aero helmet, but are constantly bobbing your head all over the place, looking left and right, up and down, etc, etc, then you won't get the time savings. This type of riding is typical in a road race, but not in a TT.

It seems daft on the surface to think such a simple piece of kit can save you so much time, but it is true - if worn and used correctly.

ugo.santalucia

Escargot wrote:

Just to add, the images highlighting flow around different shapes is highlighted on this page:

http://en.wikipedia.org/wiki/Drag_(physics)

Aero helmets are very much like wing sections whereas conventional helmets are more spherical. The images are a bit extreme but not a million miles away.

I'm not sure if this is a good example but the 1989 final TT between LeMond and Fignon was a classic where LeMond wore an aero helmet and Fignon wore nothing at all. If you look the vid up on youtube you can see that LeMond is in an aero position whereas Fignon is all over the place. How much is attributable to the helmet is anyones guess and respective power outputs are also unknown but LeMond won by about 50 seconds. Given both were pretty equal then it is very probable that the difference was down to aerodynamics

That's one way of seeing it: actually Fignon was a good climber and a mediocre time triallist, while Lemond had his strength in the Time trialling and he won his 3 tours "contre la montre". Considering that and considering all the aerodynamic aids he had over Fignon (bars, helmet etc.), 50 seconds is nothing.
I concede that had Fignon had an aero helmet... he would have probably lost the Tour anyway, just instead of 8 seconds, maybe 1...

Pross

Most club TT riders I see wearing the full kit seem to be wasting the benefit by poor position on the bike. I assume to gain the maximum benefit the rear point should be more or less resting between your shoulder blades (as in SBezza's avatar) but I've seen some people so overweight that they can't get into an aero tuck but still have all the kit.

I would say make sure you've got all the "free" benefits first i.e. that you are as fit as possible within your personal training constraints and work on your power in training. Then and only then start getting the extra kit. At the top level these things can make all the difference (Team GB's philosophy of making all the tiny changes that save .001 of a second until they add up to a winning margin) but for the majority of us there are far more serious issues that can make a bigger difference.

a_n_t

ex-pat scot wrote:

Then stuff that is more marginal (in rough order):
- shaving

Escargot

I think shaving legs has been proven to be a useless pursuit but hey, I'm happy to continue paying into Bic's

Anyway, right under our noses is this feature

http://www.bikeradar.com/news/article/how-aero-is-aero-19273

In this test at least, a helmet made quite a difference.