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10 of the best TT bike helmets

7 of the best time trial aero helmets tested, rated and reviewed by our expert reviewer



Giant’s Rivet TT was designed with pro triathlete Tim Berkel, honed using computational fluid dynamics in the wind tunnel to produce this stubby tail offering (a design which has shown to be more effective and aero in real world conditions). The ear covers have a soft lining which makes it easy to get on quickly in T1 and helps it contour to a variety of face shapes. Cooling is thanks to four ‘ports’ at the front (slightly resembling bowling ball holes) and one big 
rear port, which provided decent cooling in mild temperatures. The dial is a tad on the small side and difficult to access while you’re riding, but Giant’s Cinch Pro retention system allows for a precise fit. While our 2017 wind tunnel testing showed the Rivet to be off the pace of class-leading TT helmets, it’s super comfortable, well-vented and not crazy 

Verdict: a well-balanced, comfortable helmet at a not-too-crazy price 81%

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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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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.


To the staff: Why would you go to all the trouble to test the drag of each of these helmets but then not let the reader see the numerical drag results for *all* the helmets in this article?

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