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New road-style aero helmets from Giro, Bontrager and MET + video

Lids designed to keep your head cool while improving your aerodynamics

Three major brands have all just revealed road helmets designed with aerodynamics in mind, so here are the Bontrager Ballista, the Giro Synthe MIPS and the MET Rivale.

All three helmets are designed for general road use as opposed to being time trial-specific, hence the silhouettes being similar to those of standard road helmets. There’s nothing with a long tail here. They’re all currently being used in the Tour de France.

Bontrager Ballista

Jens Voigt actually wore a prototype of the Ballista when setting his hour record last September and Trek Factory Racing riders have been wearing Ballistas since the Tour Down Under. /content/news/130539-jens-voigt-smashes-hour-record-his-final-challenge

Bontrager says that it used computational fluid dynamics (CFD) to analyse prototypes of different shapes and vent configurations, and then took a collection of physical prototypes to be tested in the San Diego Wind Tunnel.

The aero results persuaded the designers to select a mid-length helmet with three central vents. Bontrager says that the helmet concepts were then tested on heated head forms with 36 thermal couples in order to find out about the cooling properties of each venting system. A front-centre channel is designed to draw in air for increased cooling while internal recessed channels are included to manage airflow through the helmet and over the head.

The Ballista features Bontrager’s existing Headmaster II fit system that allows you to make adjustments via a dial at the back.

Bontrager claims a weight of 262g for a medium size helmet. We have one in for review here at and ours is 266g.

You can choose between matt black, polished white, high-vis yellow, and the Trek Factory Racing team issue white. Like all of Bontrager's helmets, Ballista comes with a crash replacement guarantee: you get a free replacement helmet if it’s damaged in a crash during the first year of ownership.

The Ballista is priced £159.99.


Giro Synthe MIPS

Giro has unveiled the Synthe MIPS that will sit in the range alongside the existing Synthe that we've reviewed here on It is currently being used in the Tour de France by members of BMC, Katusha, and IAM Cycling.

Giro has already added MIPS technology to some of its other models. MIPS stands for Multi-Directional Impact Protection System and it is said to provide more protection in certain impacts.

MIPS-equipped helmets have three key features: an interior foam liner, a Low Friction Liner, and an elastomeric attachment system between them.

“In an angled impact, the elastomeric attachment system stretches to allow the interior foam liner to rotate independently around the rider’s head and redirect energy,” says Giro. “Although the system only moves a few millimetres, Giro’s testing shows that helmets equipped with this technology can reduce the amount of rotational force that may be transferred to the brain in certain impacts.”

The Synthe MIPS, like the existing Synthe, is designed to offer better aerodynamics than a standard road helmet.

“Using wind averaged drag, a formula that takes into account 72 different yaw angles and calculates a single drag measurement for a standard head angle of 30° and speed of 25mph, the Synthe MIPS is more aerodynamically efficient than any road helmet Giro tested, including the acclaimed Air Attack,” says Giro.

We don’t know which other helmets were included in that test.

The Synthe MIPS is said to weigh 260g (CPSC-certified version in size medium) – so virtually the same as the Bontrager Ballista. It will be available from late summer in four different colours at £225.

MET Rivale

MET’s new Rivale is being used by Team MTN Qhubeka in the Tour. The brand says that it is “the lightest open aero road helmet in its class”, weighing in at 230g.

“The streamlined and compact shape provides unbeatable low drag performance for its class with a saving of three watts at 50km/h (31.25mph),” says MET. “Utilising the Venturi effect [the reduction in pressure that results when air flows through a constricted space], the strategically positioned vents allow for the maximum intake of air by pulling the air through the helmet to the rear exhaust vents.”

The Rivale is made using what MET calls its HES technology. HES stands from Homothetic Embedded Skeleton and the idea is that  it ensures that the force of any impact isn’t localised in one specific region.

The Rivale uses MET’s existing Safe T Advanced retention system which is designed to have a large cradle surface area for security and comfort, and also to provide ventilation to the back of your head. You get the choice of four different vertical fit positions for the cradle and you fine-tune the fit using a micro adjust dial at the back. A retention ring goes 360° around your head to secure the fit.

The Rivale comes with lightweight Airlite straps and Coolmax internal padding.

We don’t have details on UK availability or pricing yet, although we have asked MET for that information.

Mat has been in cycling media since 1996, on titles including BikeRadar, Total Bike, Total Mountain Bike, What Mountain Bike and Mountain Biking UK, and he has been editor of 220 Triathlon and Cycling Plus. Mat has been technical editor for over a decade, testing bikes, fettling the latest kit, and trying out the most up-to-the-minute clothing. He has won his category in Ironman UK 70.3 and finished on the podium in both marathons he has run. Mat is a Cambridge graduate who did a post-grad in magazine journalism, and he is a winner of the Cycling Media Award for Specialist Online Writer. Now over 50, he's riding road and gravel bikes most days for fun and fitness rather than training for competitions.

Add new comment


brackley88 | 9 years ago

BMC look like they are cycling around with a bunch of bananas on their heads...

...that said, I do like bananas, and perhaps it is part of a new feed strategy

J90 replied to brackley88 | 9 years ago

The Met has a hint of Protone about it, although it probably won't cost stupid money. I think they could be onto a winner, nice helmet.

Also, Giro's aero helmet isn't as aero as the Synthe? Ah.

brackley88 wrote:

BMC look like they are
cycling around with a bunch of bananas on their heads...

This is the problem with the Synthe haha.

Anthony.C | 9 years ago

Indeed, good work by Bikeradar, never believe a company's puffs . . It makes me very pleased that I bought the LG Course and not the Synthe.

joules1975 | 9 years ago

Well this is what we've been waiting for ... a decent independent comparison.

Don't think Giro/Bell will like the results!

Now we just need a similar test of aero bikes!

Solo77 | 9 years ago

The Rivale is defiantly the way to go with the low weight and best ventilation. Want a faster one..... they have revealed the Manta which is gonna come in at 200g and save 10w at 50kph/31.5ish mph = 5seconds

The _Kaner | 9 years ago

Best looking MET helmet in a long time....found myself looking for it after seeing MTN Qhubeka wearing them... much more rounded/compact than their usual fare...estimated €130 which is a fairly decent price (IMO)

PhillBrown | 9 years ago

I found myself googling the Giro Synthe after spotting it on the front of the peloton with BMC yesterday... £225 for the Aero and £199 for the standard version seem rather high though!

midschool replied to PhillBrown | 9 years ago
PhillBrown wrote:

I found myself googling the Giro Synthe after spotting it on the front of the peloton with BMC yesterday... £225 for the Aero and £199 for the standard version seem rather high though!

One isnt more aero than the other. £225 is for MIPS, and £199 is for the non mips. Both have exactly the same aero properties, its the safety features that are different.

PhillBrown replied to midschool | 9 years ago

I stand corrected.

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