cthenn

Has this been asked yet? What's the deal with the unvented road helmets? I saw Rabobank and Garmin, among others, wearing really lame mining/rock climbing oversized looking helmets with hardly any vents. And then Cav has an unvented helmet which still has some of the indentations of a vented road helmet.

Is there something behind this, or is this the latest stupid bike manufacturer farce of saving 0.001 watts or making you 0.001% more aero or something? Sorry, just a bit cynical at all this "technology" that the common man eats up. Can't wait for the first guy on the next club ride to wear this helmet, thinking he's gonna outsprint his buddy to the stop sign or something.

chasm54

The helmets aren't unvented. They are standard helmets (all the kit in the tour has to be available to the ordinary cyclist - if they can afford it) but they put covers on them to make them more aerodynamic. So the indentations on Cavendish's helmet are indeed vents, with a cover stretched tightly over them.

And it isn't 0.001 watts, it's between 5 and 10. Aerodynamics really matters, and the faster you go, the more it matters. Cavendish goes quite fast.

DropDeadFred

i hate the look...bet you'll see more aero road helmet in the next year following Giro...p.s. i love that giro helmet

Bacciagalupe

Giro designed a road helmet with minimal venting, as noted above for aerodynamics. They'll only use it on flat stages, since the riders will cook if they aren't riding fast enough to generate airflow.

It's probably snake oil, but since it's a high-priced item pushed by a sponsor, the riders are probably stuck with it unless it really doesn't work.

chasm54

I don't know about the Giro helmet specifically, but the business of covering over the vents to reduce drag isn't snake-oil. They've spent a lot of time in wind tunnels determining that it makes a useful difference to the sprinters. Five or six watts is a pretty tiny percentage of Cavendish's power when he's giving it full gas, but he beat Greipel by about four inches yesterday at maybe 75kph. Small margins...

Bacciagalupe

I know you believe what you're told but to me it's BS.

Sagan aced a whole bunch of riders on Stage 1 wearing a standard helmet. For years, Cav has used a non-aero bike, and beaten sprinters on aero bikes to the line over an over and over again. And when he wins, the praise -- rightly -- goes to him and his abilities, not a helmet cover.

Timing, lead-outs, tactics and luck are what make a sprinter truly great. And you can't buy those at the bike shop.

chasm54

The fact that people win without using every possible advantage doesn't mean that those advantages aren't real. You can believe it's BS if you like. Cavendish evidently disagrees. I'm inclined to place more faith in his opinion than yours.

Shimagnolo

https://www.bikeforums.net/showthread...-Helmet-Design

Keith99

You do realize that stage 1 was on a significant climb right?

Hezz

Some are just lycra helmet covers to improve aero but still allow some air circulation. Some are so tight they may look like the helmet was designed with no vents.

I noticed both Cav and Wiggins were wearing one today. Save some energy and improve sprint on a cooler day with a little rain possible. Saving 5-10 watts is significant on final sprint and during the course of the race. Probably on really hot days it would be worse to have it on but at more moderate temperatures could give a slight edge.

Could also be part of Sky's plan to adapt to warmer riding conditions by having less cooling on head on some days.

cthenn

LOL David Millar looks like TRON. Come on...this is hilarious. There is so much nonsense in the bike techology game. Yes, it may help you that extra miniscule amount at the very top end of your output, but this is all along the same lines as the aftermarket tuner parts the kids put on their Hondas. At 7,000 RPM and 120MPH, you get an extra 5 horsepower!!! (I know, I used to be one of those dumb kids back in the day.) The average racer/rider riding at a normal pace is not going to experience jack from a slightly more aero helmet....common sense tells me that, I don't need an Excel spreadsheet to tell me otherwise

cthenn

OMG there is a ZERO percent chance in heck you get 5-10 watts from a freakin helmet. I don't even think Zipp claims their very aero wheels gives you THAT much extra watts. (Says the guy staring at his rip-off 404's across the room )

chasm54

You're mistaken. Read this article. As you'll see, wind tunnel data indicates that at 40kph a TT helmet will give you close to 10 watts over a normal vented helmet. So it's perfectly reasonable that covering the vents might give you more than half of that benefit. Your aero wheels give you the smallest bang for the buck of any of the possible improvements.

Bacciagalupe

Sure, if you're riding solo. In a wind tunnel. At a 10บ yaw.

The aerodynamic effects of a single parameter will be significantly different if you're drafting single file, or in a peloton, or if you're coming around another rider into the wind, or coming around against the wind. Unfortunately, all of these things are extremely difficult to test in a consistent and reliable manner. Heck, they can't even run a good test with one rider outdoors on a track -- the variations in wind conditions are too great. Thus wind tunnel data is very useful for TT's or if a rider is soloing off the front, but I'd think its utility in mass start races or sprints is limited.

And at the risk of increasing your blood pressure.... is 5 watts always significant?

Of course, it is drilled into us that any gain in watts is immensely important. But sprinting is not necessarily about the power.

Greipel claims that he can hit 1820 watts in a sprint. 5 watts is a 0.274% increase in wattage. Under those circumstances, 5-10 watts may not make a measurable difference in speed.

In contrast, Cavendish claims his max is "only" 1580 watts.

It's entirely possible these two are lying through their teeth. But let's assume that even if they are lying, Greipel still puts out significantly more watts than Cav -- and still loses to Cav.

So, between that and Cav beating the crap out of guys on "faster" bikes than him over and over, I'm gonna guess that the aero stuff has far less utility than the manufacturers would have you believe. Seems like sprinting is about the ability to rapidly ramp up to the 1600-1800 watt range, to maintain that kind of output for a longer duration, to conserve energy at other points in the day/stage race, the ability to read one's competitors, the tactical choice of when to sprint, as well as the rider's aero position and general aero profile, will far outweigh the benefits of something as small as an aero helmet.

I will grant that if you put Cav on a 20-pound flexy round-tube bike, downtube shifters, a 12-speed drive train, box rims and crappy tires, he'd lose a few watts. But he still might beat everyone else at the line, no matter what bike he's on.

In theory the minute aero advantages makes a difference. In practice, it's probably snake oil.

chasm54

Bacciagalupe, You seem to think I believe that these incremental improvements will turn a poor sprinter into a good one. I don't. What makes a winner is complex.

Cavendish's numbers aren't that impressive. So unimpressive, in fact, that he very nearly didn't make it onto the British Cycling development squad when he was a teenager. He couldn't put out as much power as his contemporaries, so they were going to cut him from the programme. Fortunately some of the coaches pointed out that despite being physically inferior, he kept winning. The rest is history.

But this argues in favour of the importance of aerodynamics, not against it. One of Cvendish's advantages, it seems to me, is his ability to sprint at high cadences, out of the saddle, in a lower position than the competition. Aerodynamics is key to his success because, as you point out, he is making less watts than the bigger guys like Greipel. So it makes absolute sense for him to maximise that advantage by whatever means possible.

As for whether five watts is always significant, i'd say no. Most of the time it is insignificant. But on occasions (and stage 2 looked like one of them) the margins are so tiny, why wouldn't you take an extra five watts if it was available?

mustang1

gel.eye with more airvents are lighter because there's less helmet, and more hole. so.the more holes they have, the lighter it is, and since low weigh equals high price, well there you go.

Now they are going in reverse, less holes equals better asrodynamics.

I don't mind the manufacturers marketing all this bullcrap, but when people fall for it, it makes me cringe for the human race.

Nerull

I'm curious, reading this many seem to be under the impression that the tour is a charity ride.

It isn't. It's a race. It's the race. Are these sort of improvements small? Sure. But in a race, every little bit counts.

How many millions will F1 teams dump into improvements of similar value?

Bacciagalupe

Quite the contrary. I'm saying:

• Great sprinting is about tactics, timing, fitness and training -- not raw power and bike schwag.
• The testing protocols are almost certainly relevant to solo performances, but may not be relevant to riding in a peloton or a bunch sprint.
• The improvements aren't incremental. They're negligible. No one is winning because they are using an aero bike or an aero helmet.


Yes, and that's physiology, position and training. I.e. athleticism.


If the aero helmet is hotter and offers no tangible benefit, why would you use it?

If the aero helmet offers no discernable advantage, would you even consider buying one? (Let's dispense with the illusion that sponsorship is not ultimately about selling stuff to spectators.)

Is it beneficial for a rider to hold false beliefs about gear?

Equally important is that focusing on the equipment distracts us from what is really making the difference: Tactics, timing, mental toughness, and athletic ability.

chasm54

That is merely a statement of your opinion. The figures seem to indicate that you are mistaken. If two riders perform equally on a given day, these small advantages will make the difference.




But as we have discussed, it does offer a discernible benefit. As for it being hotter, EBH returned to the team car about 30km from the finish today to swap his ventilated helmet for an unventilated one. Clearly minimising the downside while maximising the upside.

No, I wouldn't buy one. But I don't wear a helmet anyway, unless I'm racing, and when I am racing I am nowhere near the standard at which my equipment is a limiting factor on my success.