Best time trial helmets: real-world testing of five TT favourites

A look at life with five of the best TT lids available

A key component in any time-trial tester or triathlete’s kit is the helmet atop their head. It is the leading edge in the fight against aerodynamic drag.

Brands go to great lengths to test the aerodynamics of their helmets and calculate the relative advantages of each design, and the watts they may save,

The unfortunate truth however is that it’s also exceptionally difficult to make recommendations about TT helmets because their performance is highly individual. So we won’t spend any time debating the relative advantages or watts saved by these helmets, but would encourage you to perform your own testing or seek consultation from aero experts.

Instead, this is a look at how they fit, feel, and hold up to routine use. What are shortcomings and strengths that may affect comfort and speed? What are design elements that stand out? Depending on the length of time trials or triathlons that you race, your decision-making priorities will change. I used all of the helmets here in a size medium and each helmet saw many hours of use during my preparations for an upcoming 12-hour time trial. Each of them ran true to size though some are certainly snugger than others. All weights were measured on the same Feedback Sports digital scale.

POC Cerebel Raceday

BikeRadar score4.5/5

The Cerebel tops our list thanks to its comfortable interior, good ventilation, and crystal clear, easy to use visor.
The Cerebel tops our list thanks to its comfortable interior, good ventilation, and crystal clear, easy to use visor.

POC’s Cerebel is a huge departure from the company’s first go at a time trial helmet, the Tempor. Not only is it much smaller in overall size, it is also derived from an entirely different design philosophy. The Cerebel is meant to be fast in a wide variety of positions for a wide spectrum of riders. Again, we can’t confirm these claims, but with its rounded, bobtail shape, it’s easy to understand them.

The POC has a wonderfully small overall size but is still very comfortable with the shell standing off the ears nicely. Adjusting the rear dial mechanism is best done with the helmet off the head but those with smaller hands may be able to reach inside the soft tail section to do so on the fly.

The POC offers an exceptionally large field of vision, especially above the brow. Those riding with a super low position will certainly appreciate this but anyone trying to get aero can appreciate an unobstructed view.

The ventilated visor and the gills at the side of the helmet do a surprisingly good job of moving air through the helmet. That said, the POC can also be something of a whistle factory. Depending on the tilt of your head, it’s easy to experience some noise. I found that when I dropped my head, looking down, that it would whistle at me. While initially annoying, I came to view it as a reminder to keep my head up, looking forward.

The magnetic attachment of the visor is also nicely executed. For riders who like to squeeze into the smallest helmet possible, the POC makes it easy to take the visor off before putting the Cerebel on and just as simple to remove it before taking the helmet off.

The Cerebel arrives with two visors, one in a nearly clear yellow, the other a darker tint for brighter conditions. The tint is, according to POC’s website, “specially developed together with Zeiss to enhance the contrast of the road surface, allowing the rider to spot any irregularities or obstacles in time.” While at times I wish the tint was darker, it does do a good job of highlighting differences in road surface.

With its claimed aerodynamic robustness, the POC is certainly a contender for those who struggle to hold a static position, take on ultra distances, or for track athletes taking on sprint efforts. It is a comfortable helmet with a great visor. At £330 / $350, the Cerebel is the most expensive helmet in this round-up, but it does arrive with two visors and a semi-rigid carrying case, and is likely to be fast for a wide variety of athletes.

Lazer Wasp Air Tri

BikeRadar score3/5

Lazer's Wasp Air Tri is perfect for those who race in a wide variety of conditions thanks to its adjustable ventilation and accessories.
Lazer's Wasp Air Tri is perfect for those who race in a wide variety of conditions thanks to its adjustable ventilation and accessories.

Lazer’s Wasp Air Tri is something of a shape shifter. While certainly designed to be fast, it also puts an emphasis on ventilation. With an optional long tail and several different venting options, the Wasp Air is widely adaptable for changing conditions and different rider needs.

In addition to a vent at the front of the helmet, on top of the helmet is a hatch that Lazer calls the Aquaport. It’s designed to allow a rider to pour water over her head during extended efforts in high temperatures. While the feature adds weight to the helmet, if you run hot it’s probably worth its weight in gold.

The Wasp’s visor is aids in ventilation as well. It can be, using different indents in the mounting hardware, pulled away from the helmet to increase ventilation and doing so works exceptionally well. The difference between the visor closed and open can make or break an effort on a hot day. It may be slower aerodynamically, but if it keeps you from overheating you’re better off in the long, or short, run.

While I love the adjustability of the visor, the lens itself could use some help. The optics are not nearly as crisp as many of its rivals reviewed here. In particular, there are a few wavy spots near the nose cutout that make looking down at your computer a somewhat nauseating ordeal.

On the upside, the Wasp may offer some of the best situational awareness of any full coverage time trial helmet I’ve worn. It allows you to hear approaching traffic far better than most helmets that cover your ears. I’m not sure that there’s a performance correlation to made here but it’s a wonderfully quiet helmet.

Beyond the inherent versatility of the Wasp, Lazer also offers its accessory LifeBEAM heart rate monitor that reads your pulse via helmet pads. A clever inclination sensor can be installed in the helmet as well. It helps remind a rider to keep the tail of the helmet low and against the back. While certainly something that can be worn during a race, it’s also a great training tool. As mentioned above, Lazer also offers an optional longer tail section for riders who like an elongated helmet profile.

Great for riders who race in a wide variety of conditions, the Wasp Air Tri lists at $310. Additional accessories will raise that price tag, but with its versatility and the included helmet bag, the Lazer could be considered a bargain.

Specialized S-Works TT

BikeRadar score4/5

Based on the McLaren S-Works helmet, the revised S-Works TT receives side vents that Specialized calls
Based on the McLaren S-Works helmet, the revised S-Works TT receives side vents that Specialized calls

Of the helmets in this round up, the Specialized is the longest, making it arguably best for riders who are disciplined about their riding position. It’s important to keep the tail down on a longer helmet in order to make your shape as slippery as possible.

Derived from Specialized’s previous S-Works McLaren TT helmet, the newer S-Works TT is updated with patented side “gill” vents that increase airflow through the helmet. Having never tried the McLaren, I can’t comment on any improvement in cooling, but the S-Works TT is reasonably well ventilated for a time trial lid.

The Specialized arrives with a pair of great visors, one tinted for bright conditions, the other clear. The optics are crystal clear with no appreciable distortion. The visor installs with a trio of plastic clips. This mounting is secure to a point and I managed to eject a visor while riding as I tried to rotate the helmet back on my head to get the tail down. Thankfully, you can also run the S-Works TT without the visor and use regular sunglasses as many Specialized sponsored athletes do.

The S-Works TT is comfortable even on longer rides despite essentially tying with the Giro as the heaviest in the round up. Perhaps the longer tail brings some of the weight rearward aiding in keeping the tail down and head up.

Like the POC and Giro, the Specialized arrives with a zip closure, semi-rigid storage case. This keeps your helmet and visors from getting dinged up during transit.

While this test is about life with each of the helmets reviewed here, the Specialized, with its long tail, is bound to be fast for riders who can concentrate on holding a fast head position. If that sounds like you, the S-Works TT is worth a try.

Giant Rivet TT

BikeRadar score4/5

Worn to good effect by Tom Dumoulin and his SunWeb teammates, the Rivet TT is an affordable aero option.
Worn to good effect by Tom Dumoulin and his SunWeb teammates, the Rivet TT is an affordable aero option.

Perhaps the most straightforward of the helmets in this test, the Giant has a clear pedigree thanks to Tom Dumoulin, Ellen Van Dijk and their Sunweb teammates. There is no visor on offer, no shape-shifting tail section. But what you do get is a very fast helmet that is designed for a wide variety of rider positions.

Of all the helmets in the test, Giant’s was the best ventilated and the one I reached for whenever the mercury rose. Much of this has to be due to the lack of a visor. Ventilation is also aided by the four round vents at the front of the helmet, deep, internal channels, and a large exit port at the rear of the helmet.

The lack of visor does mean that you’ll need to check to see if your eyewear of choice fits inside the helmet. I typically wore a pair of Oakley EVZero Path sunglasses with the Rivet TT. Their slim ear stems and frameless design are great for riding in a low, TT position. By comparison, my Adidas Zonyk Pro glasses didn’t fit so nicely.

The Giant is fairly tight over the ears, likely a good thing in terms of aerodynamics, but can be a bit uncomfortable on longer rides. For this reviewer, the Rivet TT would be great for short, hot time trials or triathlon.

Giant’s Rivet TT is the least expensive helmet in this review at $229. But the next cheapest, the Giro, comes with a great storage case and uses a nice wraparound visor. Of course, it doesn’t ventilate as well as the Giant. It’s all a matter of your priorities. If you prefer to run sunglasses in lieu of a visor and if staying cool is a constant struggle, the Rivet TT is the way to go.

Giro Aerohead MIPS

BikeRadar score4/5

The Aerohead MIPS has a short tail but an extended brow that Giro claims helps direct airflow better.
The Aerohead MIPS has a short tail but an extended brow that Giro claims helps direct airflow better.

Giro’s Aerohead MIPS is unique in many ways. First of all, it is the only helmet in this test with a MIPS rotational impact liner. The Aerohead also has a forward-overhanging shape that Giro claims is fast over a spectrum of head positions. It certainly extends further over its wearer’s brow.

Also unique is the wraparound, magnetic visor. With the visor off and stored conveniently atop the helmet using magnets, one’s ears are exposed. Installing the visor over the face is easy enough and can be performed with one hand.

While certainly fast, the Aerohead has its foibles. The visor’s optics are decent, but not as good as the POC or Specialized. The Aerohead is within two grams of the Specialized, the heaviest helmet in this test. And with that forward overhang and abbreviated tail, it wants to pull your head down. Over a short race, this isn’t a problem, but roll along for a few hours and it can begin to wear on your neck.

Additionally, the Aerohead isn’t the coolest helmet in the lineup. The wraparound visor covers more of the face and this probably adds to the sensation of an already hot head.

But at £260 / $250 / AU$380 it is $50 less than the S-Works TT and $100 less than the Cerebel. Like them, it arrives with a semi-rigid, padded case, but only one visor. As such it’s a bargain for a super slick helmet with a well-executed visor. If the absolute lowest drag is your aim, Giro also offers the Aerohead Ultimate, a slightly smaller overall shape that deprioritizes ventilation but runs a premium £520 $550 / AU$800.

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