jackmyster wrote: Loads of people seem to be hooked on the idea that the bike helmet im using is not desighned for multi impact..- WRONG.
No you are soooooooooo wrong.
The helmet you have linked is made with "EPS" ,expanded polystyrene. It is the cheapest, worst, and has the lowest stress limit, so is much more likely to deform, of any protective material in helmets. Most white water helmets are made out of EPP, which is Expanded Polypropylene. This material is much stronger, it is chemically a much stronger polymer. This material has a much higher stress impact! Both helmets can absorb impact and be fine, however something that will break your EPS helmet will not break your EPP. Hence why an EPP helmet, most WW ones, is multi impact.
The next bit you talk about mtb helmets taking lots of hits, wrong again. In my experience all mtb crashes have one big hit then someone, usually me, is lying on the floor in pain, and walks off/hopples off. In kayaking I go over, and take some hits, roll back up and usually find myself back over taking more hits. then I might decide to swim, and I might take a few more hits, SO we need multi impact hits. Our hits are less severe but more occur, so we need a helmet to cope. a mtb helmet is designed to take one big hit and break to disperse the energy.
jackmyster wrote:ALSO just incase noone realised- With any major extreme sport such as motogp, kayaking, motocross or mountain biking ALL THE HELMETS ARE DESIGNED TO TAKE ONE SINGLE IMPACT in an ideal world. In essence every helmet is meant to take on hit and then the shell is comprimesed and is meant to be replaced. The reason why very few people replace their helmets after one hit? cost and laziness, in theory if ANY KAYAKER HAS DROPPED OR TAKEN A HIT TO THE HELMET IT SHOULD BE THROWN AWAY, the same for any sport. The only sport this is policed in is Motogp. For example, if I walk across the paddock, helmet in hand and drop it, no matter how high from the ground, that helmet is comprimsed. I must replace it ( often £500) or I am not allowed to race. ( yes there are rganisations that check all the racers helmets before race)
So much of this is wrong, i have already said why in kayaking we don't just take one hit. i have also explained how with different materials with a higher stress level the shell will not be deformed from a standard hit, for example the materials in A WHITEWATER KAYAK HELMET!!
If you read about helmets, mtb manufactures recommend a helmet is replaced after a " serious impact" i don't think dropping it from two feet counts, falling on my head off a jump and its lying in pieces does. So your comment about throwing away helmets is rubbish, only if a serious hit, or there is obvious marks on the helmet, though if unsure always buy a new one!
I can not comment about motocross as i have no experience in that. I will say that in motocross you go alot faster than in kayaking, thus a crash will have alot more energy in it, so a helmet is designed to cope with this.
Sweet's mtb helmets look so much like the rocker bet they do the same job!
I went out with a twin a while back, when drunk I once accidentally tried to kiss her sister thinking it was her, and got a slap in the face! Morale of the story if it looks the same it might not actually be the same!!!
If you look deeper into it the sweet mtb you'll find it is made of EPS! whilst the WW is made of EPP, i think i covered the difference.
If you don't believe me, despite me being a chemical engineering student who spends his time learning about different materials, then give this website a read about the different materials in a helmet: http://www.allsportprotection.com/Types ... _s/687.htm
People spent time and money coming up with the best way to protect your head, years of research has been spent on this topic. Please don't think that you instantly know best. Use the helmet for the sport it is meant.