The Bollé The One helmet allows you to convert easily between a conventional vented helmet, an aero helmet and an mtb helmet, using clip-in inserts. It’s a comfortable fit, but it’s quite an old fashioned-looking design and is significantly heavier than the alternatives. Airflow isn’t that great when the aero covers are in place either.
Lots of small vents
Poor airflow over the forehead with aero covers in place
If you’re not sure whether you want a normal vented helmet or an aero one, Bollé has a solution: the Bollé The One helmet is both.
When you unbox the Bollé The One helmet, it looks like a more enclosed aero number. But there are two removable plastic sections (the black bits) that can be pulled out to convert the Bollé The One to a standard vented helmet.
Vented, you get no less than 31 air inlets/outlets in the helmet. That’s a lot – most helmets only manage fewer than 20. The flip side of lots of vents is lots of ribs between them, so that each vent is of necessity quite small. They tend to reduce in width towards the inside of the helmet, although this does speed up airflow over the head. There’s a wide vent across the forehead, which helps funnel air to the places that get most hot when riding.
The small but numerous vents continue at the rear. Between the 31 total vents, there’s plenty of airflow over the head, although along with the bulbous helmet shape they do lend a slightly old fashioned look to the Bollé The One.
Clip in the two aero inserts and the Bollé The One helmet becomes much more enclosed and purposeful looking, although still rather bulbous. There are just two front side vents and those at the rear left exposed. You still get reasonable airflow over the head, courtesy of the two exposed front vents. But the internal channelling tends to direct the air over the sides of the head rather than the forehead, so the Bollé The One helmet isn’t as cool as, say, the new Mavic Comete Ultimate aero helmet.
The Bollé The One helmet is comfortable, with plenty of padding on the inside. There’s the standard dial adjuster at the rear to tighten the cradle around the head and wide straps with a plastic clip.
A size large Bollé The One helmet is a bit on the heavy side at 294g when used vented. Clip in the aero inserts and it’s up to 372g. That makes it one of the heaviest helmets we’ve tested. The good fit goes some way to mitigating this as the Bollé The One helmet doesn’t move around much, but you can still feel the weight. A dedicated aero helmet will almost certainly save you a significant amount of weight.
By way of comparison, a Lazer Z1 helmet of the same size weighs 258g when vented and 300g with its aeroshell in place, while the Met Manta aero helmet, similarly enclosed to the Bollé The One, weighs 252g for a size large.
The Bollé The One helmet has other tricks up its sleeve too though: if you want a mountain bike helmet, there’s a removable visor. And you can buy a safety LED light that fits into the rear centre of the helmet. If you’re just after a vented helmet, the Bollé The One Base helmet doesn’t include the clip in inserts of the Premium version.
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Paul started writing for Cycling Weekly in 2015, covering cycling tech, new bikes and product testing. Since then, he’s reviewed hundreds of bikes and thousands of other pieces of cycling equipment for the magazine and the Cycling Weekly website.
He’s been cycling for a lot longer than that though and his travels by bike have taken him all around Europe and to California. He’s been riding gravel since before gravel bikes existed too, riding a cyclocross bike through the Chilterns and along the South Downs.
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