I am wondering why the helmets used in different sports disciplines are so different, especially considering professional athletes.

Alpine skiing (source) Alpine skiing helmet

Cycling (source) Cycling helmet

Of course I understand that there are two major requirements

  • Comfort
  • Safety

For cycling it is more important to have ambient cooling, so they designed a helmet with holes to accomplish this. This does make sense to me.

However, in the time trial, maybe comfort is sacrificed

Time trial helmet (source)

Time trial cycling helmet

Now, these helmets are looking more alike, but they are still different. For the cycling I know that the tail is designed for optimal aerodynamics (and I suppose safety is still carefully tested). For the alpine skiing helmet such a tail is not use, why is that?

Side note: I know that Dtuch Olympic champion Bob de Jong (speed skating), wears is shoulder-long hair in a tight not to recreate such a tail, so it might add something?

  • Helmets intended for winter cycling aren't so different from the ski helmets. If you look at downhill mountain biking helmets and winter cycling helmets, you'll find not only that the designs are closer to an alpine skiing helmet, but that some helmets are sold for both winter cycling and for skiing.
    – freiheit
    Feb 9 '14 at 3:13
  • @freiheit Hmm, didn't think about that. So the heat argument remains, but there would still be an aerodynamic difference, or not?
    – Bernhard
    Feb 9 '14 at 8:52
  • I think the aerodynamic differences are small here. That skier isn't in a particularly aerodynamic outfit, so I doubt he's thinking much about the aerodynamics of his helmet. Ski helmets do tend to have features helping with the goggles (smooth where goggle strap goes, ridge above and below) that make venting on the sides even less likely.
    – freiheit
    Feb 9 '14 at 20:03

That ski helmet appears to be an uvex wing rc (or similar). The first cycling helmet appears to be a Kask Mojito variant. Note that both companies make both kinds of helmets.


  • Mostly constructed of crushable foam
  • An outer shell that will slip across surfaces in a collision
  • Fit adjustment systems
  • Moderately aerodynamic design


  • Ski helmet's shell is harder
  • Ski helmet has much less ventilation (it's on the top, where not visible in y our picture)
  • Ski helmet's ventilation can be closed down
  • Bicycle helmet is lighter (220g vs 490g)
  • Ski helmet covers ears
  • Ski helmet is designed to work well with ski goggles
  • Ski helmet has mount points for a chin guard

The ear coverage and ventilation differences have a pretty obvious reason. Skiing is done in sub-freezing temperatures and for a much shorter duration of time than a road race. It's important while skiing downhill to keep warm and to keep the ears covered, but with road cycling it's more desirable to maximize ventilation. Watching the other outdoor winter olympic sports, the cross-country skiers have a band covering the ears, and almost everybody else has a hat, balaclava and/or helmet so that their ears are covered.

Road racing cyclists do everything they can to keep weight down because it helps with climbing and acceleration. Also, the position of the rider and length of a road race means that any extra weight can make the neck tired. Downhill skiers are pulled down by gravity and have a more head-supporting upright posture, so a tiny bit of extra weight won't make a difference.

I believe the shell hardness difference really has 3 reasons. First, skiing downhill has a greater chance of multiple head impacts from a single crash than cycling does. Second, weight. Third, hard shells make ventilation trickier.

As for the time-trial helmet: The regular cycling helmet is made for cycling in a pack for 4 hours. The time trial helmet is made for cycling alone for a much shorter time. There's still ventilation on most time trial helmets, but it's subtle. Aerodynamics are important for both kinds of cycling, but a lot more important in that time trial, since there's never anybody to draft behind. Ventilation is still important for both kinds of racing, but more important for the longer rides, since heat and discomfort will build up over time. And, to top it off, there are regulations about the helmets that I believe wouldn't allow the time-trial helmet in a road race.

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