“They are all made to protect
from a bad blow…” Not exactly. Even motorcycle helmets don’t protect from a direct blow over about 15 mph.
You have to define what you mean by a bad blow.
One kind of blow is just bad enough to knock you out or stun you, so you can’t react to your situation. A shock absorbing liner helps, but it can be a liner that recovers. The shell should not be so stiff but that it initiates the shock absorption of the liner.
Another kind of blow markedly depresses most helmet shells, and can fracture or cave in your skull. That kind needs a stiff liner and a sacrificial, force absorbing liner. Makes for a thick, heavy helmet.
I can’t see that ww helmet design has fully matured to confront these issues.
Fortunately, I found that cheap helmets like ProTec kept me from lasting harm through almost 40 years of moderate whitewater paddling. Now I have a Shred Ready t-dub, but I don’t know if it’s functionally much better. Sweet and Gath are worth looking at, too.
Fashion and false notions of effectiveness still infect the ww paddling industry. There is no Bell of ww helmets.
catastrophic versus routine
Guideboatguy is right on. I think of a bicycle helmet like a car airbag – you hope never to need it, and once you use it, it’s done. Paddling helmets, on the other hand, are designed to stand up to multiple impacts, and particularly if you’re paddling whitewater, chances are you’re going to need it more than once. My helmet has certainly saved my noggin on several occasions.
Another difference is that most bike helmets have vents/holes in order to allow air to circulate over your head while riding. That’s fine for their intended purpose, but definitely NOT a feature I’d want on the river.
Okay…the bike helmet was a bad example
for sure, but skiing? Rock climbing, just wondering. I get the importance of covering the ocipital and ears, forhead. Just curious, that’s all.
Thanks
Coastal Paddling
If you are going to be mostly paddling out through surf, make sure you find a helmet that is somewhat hydrodymanic and stays put. Lots of whitewater helmets actually get blown off with wave impact. You also want something that will protect your head from multiple impacts over a long time. Think about being upside down and being dragged over a rocky reef or getting trashed in a rock garden. Helmet must be resistant to seawater, lots of helmets have hardware that will rust away. After trying lots of helmets I stick with Gath Gedi, but there are certainly better helmets for impact protection, but if they aren't on your head, well they don't help much. I don't use visors, bills or face shields, because they come loose or get tangled in kelp.
one more difference
The lining of my Gath kayak helmet is non-absorbing. The lining in many dry sports helmets is made to absorb sweat.
I like the Gath Gedi because it fit my giant XXL noggin and you can close the ear holes which is nice punching out through big cold surf. The Sweet carbon ballcap style look nice and has a big sun visor and will fit through a small round hatch unlike my Gath.
Try on helmets with a thin mystery material or neoprene skull cap to make sure you have enough room.
Thin shell Styrofoam
If a thin shell Styrofoam lined helmet has an impact and the foam is compressed, that foam is no good from that point on. This applies to a bike helmet and any other helmet of that design. I have a rock climbing helmet made for head impact (vs. rock fall impact) and it is a use-once helmet. If the foam is compressed, it will never again absorb shock in that area.
I would guess that paddling helmets are made with a thick outer shell so the foam doesn’t compress from most typical impacts. The one paddling helmet I have worn was that type. My ski helmet is also that type.
I just wanted to point out that helmets can vary even within a sport and the helmet design is the factor that makes them appropriate for a specific use, not just the sport that uses them.
I would use my ski helmet for paddling but it’s lined with comfy stuff that won’t want to get soaked. It’s too bad because if I ever want to play in the surf or try WW, I’ll need to have four helmets instead of the three I have now.
Dave
some good pointers on the lining…
wouldn’t have thought about the material absorbing water or not. I did learn something. 
Sacrificial helmet or not
Bike helmets are a sacrificial layer of protection. One hit and the helmet has done its job already.
Paddling helmets may have to protect against multiple hits in just ONE outing, never mind on other days.
Also, bike helmets are designed for impact protection, not necessarily pierce-through resistance. Remember the ultralightweight foam Giro helmets that you covered with a lycra half-dome? Yeah. Those have been replaced by helmets that all have at least a thin hardshell, but some of the shells don’t feel like they’d protect against a sharp pointy object. Not to mention all the venting holes and slots in bike helmets! Paddling helmets’ shells are thicker and very hard.
I don’t know this, but I would guess that rock climbers’ helmets have to protect against falls from much greater heights than either cyclists or paddlers incur. And those helmets are probably heavier for this reason.
Rock helmets are for things that fall on
you from above. If your safety rope fails, you may easily hit the ground so hard that even a full-face motorcycle helmet couldn’t save you. And you wouldn’t want to wear one of those on a long climb, believe me.
still wishing there was a like button !
We Can Talk
I bought a whitewater helmet that was marked way down. It looked really cool and I needed it for some areas that I sometimes paddled in the sea kayak. Well I bought it online so I didn’t get to try it on. When I got it it felt awful. The fix was taking out some of the inner, velcroed on, padding on the sides. Ahh much better.
Check the padding inside the helmet. Change it around 'til it feels good.
Not all bike helmets.
There are more than just the typical foam bike helmet with the thin plastic shell. There are bike helmets that are made to take multiple hits. Nutcase is one, they make all sorts of helmets for water, bike etc. Off road mountain bike helmets are made to take more than one hit and done.
Nutcase is just one example. Fox, Bell and Bern are other hard shell bike helmets that are made for the long haul.
Nutcase site; http://www.nutcasehelmets.com/collections/water
Glad you could fix it.
I had to remove all the added sizing liners in my SR t-dub, and then it just fit. First serious, expensive (but discounted) helmet I’d tried that could sit on my head and not cause pressure pain.
I’d looked at a Sweet, but it pressed on the sides of my fat head. There was so much liner, I thought I could take the barrel of a hot soldering iron and thin the sides of the liner a little. But that voids the warranty…
Not just a bad blow
Other than the breather holes and water resistance, they all do the same thing. One point I would like to make is that a tiny blow to the head can be pretty devastating. I was rock gardening with a friend and a wave knocked him over (we both don’t wear helmets) and he rolled up bleeding. A tiny contact with a rock opened him up enough to cause bleeding. A helmet would have prevented that.
helmet question
I purchased a shred ready kayak helmet. Mine came with adjustable inserts for head size, & has the HOG (hand of god) strap on the nape of the neck which prevents your helmet from slipping up exposing your forehead. My advice is to get a “kayak” helmet which does not absorb water, and will stay in place. Mine was about $80. Well worth the $$.
what is the difference between…
…rock climbing, sking, horseback riding , biking and a paddling helmet?
I don’t own horseback riding nor climbing helmets. But I do have the other 3. So here’s what it looks to me:
- Bike: light weight, flimsy, lots of vents. Probably a bad substitute for WW, though might work for surfing till you bong it once.
- Ski: heavy with a thick shell, have some vents that can be closed or opened. Though it’s still pretty hot in spring skiing even with all vents open and I’m flying down the slope at 30-40 mph. My guess it can substitute for paddling. It’s a bit heavier than my paddling helmet.
- Paddling: thin shell with some small vents. Weight half way between my ski and bike helmet.
Both the ski and paddling helmets are multi-use.
Last but not least, the ski helmet cost more than the paddling helmet.
Biggest difference
Is that kayaking helmets are really made for water use – they have closed cell foams and glues that should hold up better than other designns.
You can get a decent paddling helmet in the $80 to $100 range, and the better ones are $200 to $300.
The question is, what is protecting your head from injury worth? 30? 200? I guess it depends on the value of the contents therein. If you are only willing to buy a $30 helmet, maybe your head only has $30 worth of contents. 
Jim
Doubt it
"Is that kayaking helmets are really made for water use – they have closed cell foams and glues that should hold up better than other designns. "
All the ski and bike helmet I’ve seen would stand up to water soaking perfectly well.
People don’t just bike or ski on good weather days, you know. I’ve skied and biked in heavy downpour where I was like swimminng in costant sheets of rain. It may not be enjoyable but the helmet melting is the last thing that has any hint of happening!
“The question is, what is protecting your head from injury worth? 30? 200? I guess it depends on the value of the contents therein. If you are only willing to buy a $30 helmet, maybe your head only has $30 worth of contents. ;-)”
Wrong!
Ski helmets are much heavier and I bet my healthy head it’ll protect yours equally well if not BETTER than paddling helmets! Better yet, motorcycle helmet would protect your head WAY better than a paddling helmet. Whether you want to deal with all that extra weight and bulk is a different matter.
Price of helmet is never proportional to the protection. It’s all about marketing. Plus a bit of comfort and adjustability. They key is finding one that fits well. But that’s got nothing to do with price. Most sport specific helmets try to balance on providinng the “appropriate” level of protection, not necessarily the MAXIMUM level of protection!
Your $200-300 helmet is merely protecting a $20-30 cut rate brain if you really believe what you wrote…
doubt it
You are mixing things up. A $30 helmet is not going to do the job no matter what it is. This is not about saving money. It is about choosing a helmet that is designed for the protection that is needed and doesn’t add other problems (like unnecessary weight). That is a paddling helmet that fits, doesn’t move around at all, and is designed to take repeated hits of the kinds that occur in paddling. You cannot get that for $30.
but still higher cost isn’t always best
I agree $30 is likely too low but simply looking for more expensive even in a fully qualified water sport helmet isn’t always best. Some of the higher cost is often due to non-safety aspects. Also you need to consider your risks. If you paddle along some rocks but never in fast current and never in more than two foot surf then any super impact absorbing ability is likely not needed. Sure something extra bad CAN happen but using that logic we’d all carry shark repellents, huge booms with reflectors for boat traffic and who knows what else. So understand the benefits of each helmet and compare it to your expected situations.