We continue our guide to aero bike helmets for triathletes...
Looking back to the Giro Aerohead (which still performs admirably in the wind tunnel and is legal to race in), the changes over the 25 years since it appeared have hardly been dramatic. Every now and then some experimental designs materialise that buck the traditional shape.
Most recently the Darth Vader-like POC Tempor caused a bit of a stir, but you’d have to be pretty self-confident to wear one, especially in orange. Tri-friendly tweaks, such as the external adjustment dial and magnetic buckle included on the Lazer Tardiz (below), are always appreciated but are hardly game-changers.
Rob Wesson believes that there will be more steady progression in the years to come. “There will certainly be experimentation with the shape. We’re already factoring course profiles and weather patterns into our designs and this will only become more sophisticated.
"Every time we go in the tunnel we learn a bit more and can make a few tweaks. There won’t suddenly be any crazy shapes though; it’ll be evolution not revolution. It’s worth looking at the automotive industry; they slowly tweak their models towards the ideal.
"You could have a really great idea and it could work really well but, if the market isn’t ready for it, it’ll fail. Change will continue to be incremental.”
If the shape of aero helmets is going to evolve slowly, what other developments could we see? We’re certainly hoping that manufacturers will continue to tweak vent placement and design or even develop new cooling solutions in the quest for the Holy Grail of ventilation that doesn’t compromise aero integrity.
A guaranteed non-misting visor would also be fairly high on our wish list. With the technology already appearing in ski goggles, a head-up display (HUD) for visors is surely a possibility. For keeping a solid head position, HUDs definitely make sense. It’ll be interesting to look back in another 25 years and see how different the cutting-edge helmets on the Queen K Highway are compared to 2015’s designs.
Aero helmet essentials
Wind tunnel data isn’t the only thing to consider when it comes to picking an aero lid…
Designed to slide along the road if you crash and slip through the air as you ride, the shell is what gives a helmet its aerodynamic profile. The shape will generally be a teardrop, but there’s considerable variation when it comes to tail length. Most manufactures opt for a smooth surface but some use golf ball-like dimples, claiming they create even more zip.
One of the key determining factors as to how well a helmet will perform for any given rider is the shape and length of its tail. Long tails can be very aerodynamic provided they stay flat against your back but, if you drop your head or don’t ride with a flat back, any gains can easily turn into losses. A stubbier tail or tail-free helmet could be a better choice.
The expanded polystyrene (EPS) foam is what absorbs the impact energy of a crash and is designed to be sacrificial. This is why you should diligently check your helmet after a crash, or if you drop it, even if there’s no visible damage to the shell.
On an aero helmet, vents are always going to be a compromise between cooling and aerodynamics. By sucking in air they generate turbulence, and therefore drag, but without any ventilation you’re likely to overheat.
Logic says that a visor smooths out the frontal profile of your helmet and face and should therefore decrease drag. However, independent wind tunnel testing on some designs has found they’re faster with the visor removed. You’ve also got to factor in potential overheating and fogging issues but, on the other hand, they look cool.
Cradle and straps
Like a conventional helmet, the cradle secures the helmet to your head and is usually adjusted using a ratchet, dial or a similar mechanism. Straps tend to be fairly standard too but, if you’re in the pursuit of marginal gains, trim the ends down once they’ve been correctly adjusted.
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