Why do aero helmets look like fancy dress?

Ex-pro racer and aerodynamics expert

Ex-pro racer and aerodynamics expert

Andy Turner

Andy Turner is an ex-pro racer turned Aerodynamicist. He works with Venturi Dynamics at the Silverstone Sports Engineering Hub, where his expertise assists Olympians and professional athletes in understanding and refining their aero performance. He knows a thing or two about what works and what doesn’t when it comes to saving watts in the wind.

When it comes to marginal gains, aero-tech remains a key battleground at the World Tour level. Rapid prototyping and improved access to simulations and testing technology are driving incremental advances that make professional cycling almost as difficult to keep up with as Formula 1 in terms of aerodynamic developments. It hasn’t yet matured to the extent that wings have developed winglets — perhaps thankfully — but races, and in-particular time trials, can be won or lost in the wind tunnel, and the new equipment that delivers these ever faster times is pushing cycling’s well-established aesthetic proclivities to their limits.

The reality is that whilst the shapes created are often challenging to look at, they work. The advantages can now even be tailored to not just the discipline (as we see in TT frames) but also to the specific needs and shapes of an individual. The Specialized TT5 helmet was primarily designed for Remco Evenepoel on the Soudal Quickstep team, for example.

Helmet development is in the spotlight here for its obvious impact on aesthetics but it forms a massive part of the aero-equation and I suspect will remain critically important in time trialling, thanks to the relative stability of the rider's head in this discipline.

Unlike some of the other developments over the years, such as fairings for our rear mechs which make little to no real-world difference, the gains here can be really meaningful, as the head makes up a large proportion of the all-important frontal area - responsible for so much of the drag that slows us down. Much more in the case of the rider’s head, for example, than say the frame or wheels.

Last year, Visma-Lease a Bike turned out with a helmet design only a mother could love, in the Giro Aerohead 2.0. It looks challenging, to say the least. It should really have been identified with a suitably disparaging name like the ‘Speed Sniffer’ SL8 concept which landed with an audible gasp when Specialized’s update to the SL7 broke cover. The ‘Aerohead’ features a massively elongated front, and flared rear of the helmet, which means it wouldn’t look out of place on the Death Star.

Aero isn’t new of course, but neither are the inter-galactic looks. The tech has just got a lot more advanced. The speed benefits have been clear since Greg LeMond won the 1989 Tour De France. Who can also forget Armstrong and Ulrich’s long-tailed helmets in the early 2000s?

A big difference now is that more sport cyclists understand the benefits of aero-tweaks. It also seems that pro-tour technology has a now routine habit of finding its way into our shopping baskets and onto our own bikes much more quickly than it may have done in the past. Sometimes, regardless of the cost-benefit analysis. The worry is here that we’re all going to be riding around in fancy dress.

I can understand that concern. My own work optimising athletes positions in the wind tunnel used to be delivered for brands and pro teams almost exclusively, but amateur riders are increasingly interested in their own aero performance to aid their racing or experience, and investing heavily in their hobby.

As a result, most of us now understand the benefits of bringing one's shoulders in, or dropping one’s head. And at any amateur TT, or triathlon these days, you can see people adapting positions to bring their heads closer to their hands or closing the gap between them.

What about road racing?

But will more focus on aero performance mean these crazy-looking helmets break out of the TT scene and catch-on in road racing too?

Well, the idea behind them is sound. They are extremely effective at smoothing the transition of airflow all the way from the hands, over the head and shoulders and out over the back. This reduces turbulence and friction drag. The likes of Rudy, Giro, and many other helmet manufacturers will now sell you an incredibly effective aero helmet. Still, it’s hard to imagine them being a very high-volume play for those brands, given the niche nature of time trialling and more importantly, just how out of place off the bike or outside of a time trial they would instantly seem.

Visma-Lease a Bike bike is convinced the looks are worth it. They are already using the Giro Aerohead time trial helmet in road races, such as the Tour of Oman earlier this year. It is not the very latest and most extreme space-helmet effort from the brand, instead they are using the older, first generation Aerohead helmet, as used in 2015 to win the opening prologue in that year’s Tour de France. It was a smaller, profiled, smooth helmet designed to have a small frontal area. It turns out it is a very quick design for road racing due to its capacity to work in the context, and not impact aerodynamic drag negatively when moving the head around.

Many do not work so well in so many conditions though. And, practically all ultra-slippery helmets forgo quite a lot of ventilation in favour of maximal aerodynamic performance. This is one of the reasons why in triathlon, and especially long course or Ironman competitions, athletes will often opt for an aero road race helmet, rather than a specialist time trial set-up due to the comfort and practical advantages. There is also a lot more positional movement on the road. It’s just the nature of the road race. You move your head around more to climb, sprint or to simply be aware of your surroundings, so a helmet that’s ultra-sensitive to position just doesn’t make as much sense.

To counter that slightly, my time in the wind tunnel has shown me that helmets like the POC Tempor can be incredibly fast on certain riders. However, when moving the head upward slightly, it can then become one of the slowest options. That particular POC lid was launched way back in 2012 but only received more widespread use much more recently when the HUUB Wattbike team started using it.

Even then, these helmets are quite rider-dependent. A good example is the British Cycling pursuit team, who often wear different helmets to each other with the sponsor's logos removed, as do Lidl Trek in time trials. This is because for each individual rider, a specific and individual helmet is generally the fastest in their own most efficient position. It’s another reason why these latest time trial helmets vary so much and so often in their designs.

What’s right for you?

If you do want to go down the aero helmet route, or just want to optimise with one of the less challenging-looking road-style helmets, you can read reviews of the best helmets and make decent gains via a lid with fewer vents, or go the whole hog to find out which one works best for you and your position in the tunnel, and you may well find bigger gains.

You don’t need a tunnel however, and there is now some good tech which will allow you to do it yourself; if you can control and account for conditions as best you can, you can get by with some software and some consistency.

Non-cyclists might assert that we already wear some pretty outlandish gear, but do these new ultra-aero designs benefit real riders out on the road, and are we ready to start stepping out in them? I don’t think so.

And, if they cross the rubicon into fancy dress (as most, if not all, of them now do), I just don’t think the time is coming where many of us are going to tolerate them on the Sunday run too.