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10 of the best TT bike helmets

6 of this year's best time trial aero helmets tested, rated and reviewed by our expert reviewer



The Drone WB has had a tweak for 2017 with a new magnetic visor attachment and a subtly revised shape that’s claimed to save a couple of watts. We never managed to knock off the old visor in a race, but it was easy to do and then fiddly to reattach. The new magnetic visor is more secure for fumble-proof transitions and can be placed one-handed.

Yet MET have missed a trick that Giro didn’t – the Drone’s visor can’t be mounted upside down. Still, owing to its wide shape, the opening makes for a large target at which to aim your head while in a hurry. The bulbous shape is designed to deflect air over the shoulders when in a low TT position at the cost of greater frontal area. So it was no surprise when, despite a strong showing in the tunnel head down (just 3.4 watts off the best), the 442g Drone was second last in a head-up position.

Verdict: Airy, fairly light and fast in a low position but slow when riding with the head up 89%

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The evolution of the Wasp continues with this new Tri version of the short-tailed Air model, bringing a useful extra vent on the top and a clever sprung flap through which you can squirt water to cool down, which is easy to use and effective. The 424g Wasp comes with a swappable extra-short tail and a bag.

Available separately are a very long tail, LifeBEAM heart rate monitor and Lazer’s Inclination Sensor that beeps when you move your head out of your programmed aero position. The visor can be pulled into two forward positions to reveal brow vents but the mechanism on this is so stiff that you can’t operate it while riding. It’s comfortable, stable and wicks sweat away well. Head down it was the slowest by 10 watts, but head up - what it was designed for and how many age-group triathletes ride – it was second fastest, just 3 watts off the S-Works. 

Verdict: Best cooling, light, feature packed, tri-focused but position sensitive 91%

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The Split is a deceptive helmet in a couple of ways: it appears to lack venting yet it’s designed to draw air in from the front and then channel it through to the rear exhaust vent; the wind catching under the brow feels anything but aero, yet the Split tested decently when head up in the tunnel (3.9 watts off the best). It was poor when head down in an aggressive position, though, over 13 watts down on the Giro, failing to meet our back neatly, though it may work better for other riders with different postures. Its decent aerodynamics are matched to a fair weight and reasonable cooling; the air hitting your face is refreshing but there’s no breeze to be felt inside even over a shaved head on a cool day. The need for glasses adds one more element to transitions, too. It’s well priced, at least. Once good, now overtaken.

Verdict: Value, speed, ventilation,comfort... the Split is decent enough at all of them 73%

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The final verdict

The test results show why we test in two positions – the rankings are completely different. Ask someone to take a photo of your race position to guide your choice.

The Scott and Giant are more affordable but were off the pace and easy to rule out. The other four are all contenders, hence the close scores. The MET and Giro are both very fast in low positions and airy. The MET is great for broad riders as it helps air past your shoulders, the Giro tested faster and has the cleverest magnetic visor. Both, though, tested poorly for more typical
age-grouper positions.

The S-Works TT is the only helmet to be really fast in both positions and it’s also the lightest, so it’s hugely appealing, but it’s costly and the venting is minimal.

Our winner is a helmet that tested last in a low position in the wind tunnel, the Laser Wasp Air Tri. However, very few of us ride that low and in a more sustainable posture it offers great speed to go with its superior cooling. Lazer’s focus on the needs of our sport has produced a great tri helmet. 

How we tested
To find out how fast these helmets are, we took them to the R J Mitchell wind tunnel at the University of Southampton. We tested them on a rider on a tri bike in two positions. The first, head up to put the helmet in clean air. The second, head down in line with the spine to test each helmet’s ability to integrate with the rider. Some big differences in results for each position underlined the importance of choosing a helmet that suits you. We tested at 0º (straight into the wind) and at 30mph. That’s above typical tri race-day speeds but it adds resolution to the data.

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So, what does the heads-up/heads down position look like?

It would also be helpful in these comparisons to see a relative sheet of drag so we can compare helmets. The way I read this, the Lazer must have the best venting on earth.

It's only a little less expensive than the S-Works, much slower heads down, and only a little quicker than the Scott that isn't liked heads up.

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