Whats faster no helmet or Aero helmet?

Langman

I am asking this question because I have been given 2 differents answers by 2 people so please can some one clear this up....

What's faster no helmet at all or Aero helmet in a time trial?

Cheers

Pokerface

Langman wrote:

I am asking this question because I have been given 2 differents answers by 2 people so please can some one clear this up....

What's faster no helmet at all or Aero helmet in a time trial?

Cheers

No helmet. If you have no hair.

Aero helmet should be faster for the way it helps air flow off you. I'm sure someone has a link to the proof you seek...

Langman

I thought aero helmets must be quicker but wanted to see what you guys thought. What sort of time savings are we talking over 10m .... 10 seconds????

chrisw12

Langman wrote:

I thought aero helmets must be quicker but wanted to see what you guys thought. What sort of time savings are we talking over 10m .... 10 seconds????

I honestly think that this is one question that you need to find out for yourself as the answer could change depending on your position (and temperature and race length.)

I tried to test this in the summer with an outdoor track and a powermeter but couldn't get enough runs in to gain any real insight. To cut a long story short, in some positions the helmet seemed better but in others no difference. (from memory, I don't think it was ever worse. :?: but again, no where near enough data to be conclusive on this.)

After testing I did my main A race, a 100 mile tt and went without the helmet to stay cool. In hindsight this was a mistake as I never felt in race mode without my 'lucky' helmet.

In the spring I'll revisit this.

chriskempton

There is some (admittedly sketchy) research someone did comparing aero helmets, where they also tested a bare head, and I think it came out as very similar to one of the better aero helmets. Can't remember where it is, but will see if it comes back to me and post it...... :roll:

Alex_Simmons/RST

It depends on individual morphology and head position. Some people can get large differences between helmet options, other much less so.

Field testing with a power meter or a trip the the wind tunnel is needed to assess.

Muzzlehatch

No helmet = less frontal area, which is good, but the down side to this is that there is no tapered section behind to smooth off the disturbed air.

Therefore, the fastest way would simply be to stick a cone to the back of your bald head (e.g. child's party hat).

Pokerface

Langman wrote:

I thought aero helmets must be quicker but wanted to see what you guys thought. What sort of time savings are we talking over 10m .... 10 seconds????

The real boffins will tell you that savings are never measured in terms of time, but in percentages - as it takes away extraneous factors. So, an aero helmet may save you 1% - which for YOU may translate into 10 seconds. For me it might translate into 30 seconds as I'm more powerful, etc. But thinking in terms of percentages is hard to understand as we all just want to know how much TIME we're going to save.

Some people CAN and WILL save themselves up to 30 seconds in a 10 mile TT with an aero helmet over a standard helmet. Not sure what the savings is over no helmet.

Other very important thing to note - some races require the use of a helmet, therefore you can't ride bald. Your local club TT probably won't, but a CTT event probably will.

andrewgturnbull

Pokerface wrote:

Other very important thing to note - some races require the use of a helmet, therefore you can't ride bald. Your local club TT probably won't, but a CTT event probably will.

Hi there.

More likely to be the other way round... CTT sanctioned races do not insist on helmets. My club races do, plus all cycle events up here in scotland under the SCU banner make helmets compulsary (we don't do CTT up here).

Cheers, Andy

Pokerface

andrewgturnbull wrote:

Pokerface wrote:

Other very important thing to note - some races require the use of a helmet, therefore you can't ride bald. Your local club TT probably won't, but a CTT event probably will.

Hi there.

More likely to be the other way round... CTT sanctioned races do not insist on helmets. My club races do, plus all cycle events up here in scotland under the SCU banner make helmets compulsary (we don't do CTT up here).

Cheers, Andy

Sorry - you are correct (unless you're under 18 - in which case you DO have to wear one for a CTT race).

Langman

When I asked this question I thought the answer would be pretty straight forward, but it seems not to be. I have bought a helmet online and am waiting to receive it . I shall then give the definative answer, which is quicker and by how much.

Alex_Simmons/RST

Langman wrote:

When I asked this question I thought the answer would be pretty straight forward, but it seems not to be. I have bought a helmet online and am waiting to receive it . I shall then give the definative answer, which is quicker and by how much.

So you are testing with a power meter then. Cool.

Otherwise, you can never really know how to account for all the uncontrollable variables.

Langman

Well, I'll have a good idea. Same course same weather same effort and one will be quicker.

jim one

There was an article on bikeradar last year from specialized that suggested an aero helmet saved a whole 7 watts over a normal helmet. How a normal helmet compares to no helmet I can not remember.

Alex_Simmons/RST

jim one wrote:

There was an article on bikeradar last year from specialized that suggested an aero helmet saved a whole 7 watts over a normal helmet. How a normal helmet compares to no helmet I can not remember.

The impact of any helmet is completely dependent on the individual using it.

There is simply no way to make generalisations about the aerodynamic impact of helmets.

Anonymous

Alex_Simmons/RST wrote:

jim one wrote:

There was an article on bikeradar last year from specialized that suggested an aero helmet saved a whole 7 watts over a normal helmet. How a normal helmet compares to no helmet I can not remember.

The impact of any helmet is completely dependent on the individual using it.

There is simply no way to make generalisations about the aerodynamic impact of helmets.

wear the pointy bit at the front, like concorde...

Pokerface

Alex_Simmons/RST wrote:

jim one wrote:

There was an article on bikeradar last year from specialized that suggested an aero helmet saved a whole 7 watts over a normal helmet. How a normal helmet compares to no helmet I can not remember.

The impact of any helmet is completely dependent on the individual using it.

There is simply no way to make generalisations about the aerodynamic impact of helmets.

Actually - it is VERY easy to make generalisations! Because they are so, well..... general.


The specific details are much harder to come by.

Harry182

It's worth noting that up until fairly recently the aero timetrial "helmets" used by the the pros were really just head fairings, ie they offered no crash protection and only served to reduce the rider's wind resistance. IIRC, it's only been in the past couple of years that the UCI has required protective helmets be worn during timetirals.

Assuming that until the UCI started enforcing protective helmets be worn during timetrials that the riders could have chosen to ride helmetless and didn't, it would seem to suggest aero helmets are faster than no helmets.

(I'm assuming that aero helmets are effectively as aero as unprotective head fairings.)


Also, I recall a magazine study claiming that (normal) bike helmets are more aero than uncovered heads of hair but less aero than a clean shaven head.


I reckon the aero helmet is faster than no helmet. (However, we're still only talking seconds over a 10km course.)

fnegroni

Harry182 wrote:

Also, I recall a magazine study claiming that (normal) bike helmets are more aero than uncovered heads of hair but less aero than a clean shaven head.

I have short hair, and event though I can't measure the aerodynamics involved, I can categorically say that without helmet I am a lot more comfortable, my head is cooler, my neck is less strained, and I can therefore deliver a better performance.

Admittedly I have a 4 yo helmet, well vented and 260 grams, but still not the latest Limar Pro ultralightweight... you get my point.

tarquin_foxglove

The difference between an aero helmet and a bare head with a ponytail?

DVV

Frontal area is not the be-all and end-all of aerodynamic drag - e.g a teardrop shape with the same frontal area as a sphere will experience less drag over a wide range of operating conditions. Similarly, an aero helmet could most definitely reduce drag as compared to wearing no helmet, but this effect is likely to depend upon body position etc. A simplified example would be that if you were sat fully upright an aero helmet make censored all difference, whereas if you are in a full-on tuck the aero helmet would make more of a difference.

Alex_Simmons/RST

Pokerface wrote:

Alex_Simmons/RST wrote:

jim one wrote:

There was an article on bikeradar last year from specialized that suggested an aero helmet saved a whole 7 watts over a normal helmet. How a normal helmet compares to no helmet I can not remember.

The impact of any helmet is completely dependent on the individual using it.

There is simply no way to make generalisations about the aerodynamic impact of helmets.

Actually - it is VERY easy to make generalisations! Because they are so, well..... general.


The specific details are much harder to come by.

It's easy to make inaccurate generalisations.

Alex_Simmons/RST

Harry182 wrote:

It's worth noting that up until fairly recently the aero timetrial "helmets" used by the the pros were really just head fairings, ie they offered no crash protection and only served to reduce the rider's wind resistance. IIRC, it's only been in the past couple of years that the UCI has required protective helmets be worn during timetirals.

Assuming that until the UCI started enforcing protective helmets be worn during timetrials that the riders could have chosen to ride helmetless and didn't, it would seem to suggest aero helmets are faster than no helmets.

That and sponsorship by helmet manufacturers.

Harry182 wrote:

I reckon the aero helmet is faster than no helmet. (However, we're still only talking seconds over a 10km course.)

Well in aero testing of two helmet options for a rider I coach that set a new UCI world best record for the masters hour (48.317km), the difference between two aero helmets was equivalent to over 1km on the record.

So I would suggest that the impact can be quite substantial even between aero helmets.

However the same two helmets on another rider with a different head postion may well be quite minimal.

Bhima

I just saw some photos of myself sprinting and, even though my head is right down low, the back of my helmet was sticking right up! :shock:

So I took off my helmet and got a friend to take a photo of me sprinting again. I'm not sure if I was going faster, but there was a significant reduction in frontal area.

However, when i'm seated, on the drops with my back parallel to the ground, really tucked in, I tend to keep my head down and the helmet is not exposed to the wind in the same way (from what I can see from the photos).

So... Maybe you could take some photos and see what things look like... It's not a very scientific approach, but maybe, for me, it'll save a couple of watts in future, now that i've developed a different head position when sprinting. You could use photographs to see how you would have to position your head to make it look more aerodynamic and experiment from there...

dave milne

Armstrong always wore one from 99 onwards and he wasn't one to miss a trick on the technology side.

Langman

dave milne wrote:

Armstrong always wore one from 99 onwards and he wasn't one to miss a trick on the technology side.

This is a good point, it seems aero helmets are quicker afer all. Lemond wore one in 89 thinking it was quicker, it turned out it actually cost him 12 seconds, but the thought was that it was possible to make you quicker using an aero helmet. Surely technology must have allowed this to happen buy now 20 years later.

cougie

Pokerface wrote:

Some people CAN and WILL save themselves up to 30 seconds in a 10 mile TT with an aero helmet over a standard helmet. Not sure what the savings is over no helmet.

Doubt its as much as 30 seconds in a 10.

The winners at IM Kona this year both rode with normal helmets. If your rule is right - the aero helmet would have saved them over 5 and a half minutes - which is considerable.

Kona is hot mind you - but a lot of people still ride with aero helmets there.

Langman

I think from experience no helmet gives you 30 seconds over a normal £50.00 helmet.

Alex_Simmons/RST

cougie wrote:

Kona is hot mind you - but a lot of people still ride with aero helmets there.

The heat question is a key factor at Kona and several athletes will choose not to use one for that reason - the more you ventilate an aero helmet, the less aero it becomes.

I know that in aero testing this year, I borrowed a Limar aero helmet and it made very little improvement to my aerodynamics versus my regular mass start helmet.

I do however have a better helmet to test, as well as another that I suspect will be aero in name only.

One thing I keep repeating, there is no standard improvement factor for any given helmet on any given rider. It is a highly individual thing.

I'm not sure how the Lemond 12 second claim was established - unless they subsequently did aero testing to determine the variance in CdA.

DaveyL

I recall an interview with Lemond on Competitor Radio, where he says the aero helmet cost him time because of his ADD - he kept looking down at his speedo rather than keeping his head up all the time, turning the helmet into a sail!

It's something I see quite a lot of - and the aero helmet is only going to work (if at all) if you keep your head up!

Alex_Simmons/RST

DaveyL wrote:

I recall an interview with Lemond on Competitor Radio, where he says the aero helmet cost him time because of his ADD - he kept looking down at his speedo rather than keeping his head up all the time, turning the helmet into a sail!

It's something I see quite a lot of - and the aero helmet is only going to work (if at all) if you keep your head up!

When coaching an athlete for the World Masters Hour record this year, I removed his power meter from view for that very reason.