Aero and headwinds

gloomyandy

So the general comments on aero bikes and wheels is that unless you are riding 20+ mph they don't hep that much. What about headwinds though. After battering at 15mph or so tonight into a 18mph headwind it made me wonder if an aero bike and wheels would have helped at all?

hipshot

There will obviously be a small relative benefit in using aero equipment into a direct headwind, but not so much when you make a turn and it becomes a strong crosswind.

It goes without saying that a good aero position in the drops will make a more tangible difference.

Headwinds are grim :twisted:

Duncanandthemachine

What he said!

sloppyschleckonds

The lump in the saddle makes the most difference

VTech

Ive been doing some 360 degree tests and there is no gains that I have found from an aero bike, having said that, I have only personally tested a Felt AR4 over a Triban 3 from Decathlon.
At certain points the Aero is way better than the Triban but side on the Triban is much better.
I am going to be doing a review and will post the findings but if your after a slipstream from an aero bike I am doubtfull you will see a gain.

hatch87

As above, I have aero wheels, but wouldn't take it out in strong winds because of cross winds.

greasedscotsman

VTech wrote:

Ive been doing some 360 degree tests and there is no gains that I have found from an aero bike

VTech wrote:

At certain points the Aero is way better than the Triban

Make your mind up. :roll:

VTech

greasedscotsman wrote:

VTech wrote:

Ive been doing some 360 degree tests and there is no gains that I have found from an aero bike

VTech wrote:

At certain points the Aero is way better than the Triban

Make your mind up. :roll:

They key was in the 360 degree testing :roll: :roll: :roll: we can all do funny faces
The info I gave was very valid, on testing you will find that there is no overall gain on aero bikes, the gains are in slipstream but life isn't like that, you are only in slip at certain times so overall you have to weigh in the good and bad and the side-on negatives in my findings outweigh the frontal gains.
I hope this clears it up for you, if not I am happy to explain further :P :shock: :?

greasedscotsman

VTech wrote:

The info I gave was very valid

Really?

VTech wrote:

The point is that when using a wind tunnel you can make most changes look good but that doesnt mean it performs where it counts.

viewtopic.php?f=40013&t=12905337&start=80

VTech

greasedscotsman wrote:

VTech wrote:

The info I gave was very valid

Really?

VTech wrote:

The point is that when using a wind tunnel you can make most changes look good but that doesnt mean it performs where it counts.

viewtopic.php?f=40013&t=12905337&start=80

Im not sure I understand your meaning ?
The link you just gave backed up 100% what ive written above.

greasedscotsman

Do you think? As I understand it your saying that what works in a wind tunnel doesn't always work on the road. So as interesting as your data might be, it isn't necessarily correct.

greasedscotsman

Oh and you did take the frame bag off your AR4 before testing it?

(There you go, another funny face for you...)

VTech

I think the issue is taking bits from one post and bits from another.
There are facts with wind tunnels but they are facts based on a single test, overall is a different matter.

Something can flow head-on but be worse side-on.

You have to judge wether the frontal slip outweighs the side negatives.
The best way to do this is to measure degrees of +/- and make an argument to either way so if a bike flows 23% better due to design, it is highly possible that they have taken the frontal slip in that quote rather than the entire rid-ability of the bike which in total would/could be worse.

My felt is more aero than the triban, but only on frontal slip. Side-on its not as good.
I have to judge wether or not I can ride in slip for a 30-50k ride in order to ascertain wether or not the felt is less draggy than the triban on an entire ride.

greasedscotsman

VTech wrote:

I think the issue is taking bits from one post and bits from another.

Really? Why is this a problem? Have you changed your mind on something?

VTech wrote:

There are facts with wind tunnels but they are facts based on a single test, overall is a different matter.

So what your saying is that in a wind tunnel one bike is better than another, but this isn't necessarily the same out on the road.

VTech wrote:

Something can flow head-on but be worse side-on.

You have to judge wether the frontal slip outweighs the side negatives.
The best way to do this is to measure degrees of +/- and make an argument to either way so if a bike flows 23% better due to design, it is highly possible that they have taken the frontal slip in that quote rather than the entire rid-ability of the bike which in total would/could be worse.

Who is they? What quote?

VTech wrote:

My felt is more aero than the triban, but only on frontal slip. Side-on its not as good.

You need a wind tunnel to work this out?

VTech wrote:

I have to judge wether or not I can ride in slip for a 30-50k ride in order to ascertain wether or not the felt is less draggy than the triban on an entire ride.

I'd just ride which bike you like best. I think your over thinking this too much.

racingcondor

Worth noting that 'side on' is relative.

In a 10mph wind at 90 degrees from the front if you're doing 20 mph the effective wind direction is 30 degrees off headwind. Essentially it's of limited value testing for wind directions >45 degrees because it takes a hell of a strong wind to change wind direction relative to the rider by that much (assuming your rider with the aero bike is race fit etc and therefore looking at buying aero for gains that might actually be measured against anything but themselves on Strava).

Personally I don't really buy into Aero (at least not for frames) but that's because I think that in most cases ride quality suffers and that's not something I'd give up for a small gain.