In terms of seconds gained for pounds spent, a time trial aero helmet is potentially one of the best biking upgrades. However, before you head out and buy the most expensive and outlandishly profiled helmet available, think about the following points….
The helmet has to suit your riding position. There’s no point having a long-tailed helmet if you roll or drop your head a lot. The tail has to sit flat along your back or it can easily create rather than minimise drag.
Also consider comfort; aero helmets often won’t deliver nearly as much ventilation as a conventional road helmet. That’s not an issue for spring UK races, but a major consideration at, say, Kona. Finally, don’t forget transition. A helmet has to be easy to get on and off and tweak on the move.
Here are 6 of this year’s best aero helmets:
Taking both head positions into account, the S-Works TT from Specialized is the fastest helmet here. It was the most aero when head up and just 1.7 watts behind the Giro when in a deep tuck. That makes it versatile for different courses, riders and positions. It also has a very securely mounted visor that doesn’t impede transitions once you’ve got the hang of spreading the ear flaps.
Ventilation comes from the slats behind your ears and air to your face under the shallow visor; it works but is arguably designed more for TTs than triathlon and it wouldn’t be our first choice for a long, hot event. It’s fine on cool days, though, and, at 419g, it’s also the lightest here and is the only one to come in a travel case. It’s comfortable and stable, though it feels a different shape to other Specialized helmets, so try it on carefully.
Verdict: Super-fast head up or down. Light, but pricey and less vented for warm riding 91%
Buy from evanscycles.com
We’d understand if you were tempted to buy this helmet for the looks alone but before you do, at least read to the end. The Aerohead is well ventilated, with two ducts in the shell feeding internal channels to exhaust vents, and the fit is comfortable thanks to the RocLoc Air retention device and plush padding.
The wrap around lens – a Carl Zeiss item, no less – attaches very securely with magnets and can also be placed inverted above the brow to make transitions slick. It’s easy to reach up and place the visor one-handed. It also features MIPS for added safety at the cost of some stability on bumpy roads. Best of all, the Aerohead was the outright fastest helmet when in an aggressive position, edging out the MET and S-Works. However, head up it was plum last, 7.4 watts back, it’s prone to misting on damp days and it’s the heaviest here at 501g. www.giro.com
Verdict: a great visor, plush and,super fast, but only if you can get your head low enough 90%
Buy from evanscycles.com
The Rivet TT was designed in CFD with input from top Ironman Tim Berkel. Giant say the upper dimples improve airflow and that the brow vents are drag neutral. It only comes in two sizes, covering 51-59cm, and it felt small on a 58cm head, so the Rivet isn’t for big heads. It’s light at 423g and feels even lighter because it’s stubby and well balanced on your head. The brow vents don’t produce much breeze, though, and it’s the air passing noisily over your temples that does most of the cooling. A stubby tail is more effective if your position doesn’t allow a long tail to sit on your back or you’re prone to dropping your head, but in the wind tunnel the Rivet rated poorly – 5.8 watts slower head up, a hefty 14.6 watts slower head down – and the need for glasses slows transitions. If you need a more affordable helmet than the best here, look at Bell’s Javelin. www.scott-sports.com
Verdict: A low price and light but off the pace in the wind tunnel in both head positions 67%
Buy from www.rutlandcycling.com
Continue reading our guide to this year's best TT helmets (2/2)