[quote]First and foremost, it's important that the materials offer good elasticity and damping characteristics as well as absorbing shocks, since this is the only way the rider can be protected from undue vibration.
Well, not the 'only' way ... new shorts, different saddle, even a change of tyre pressure or bike set-up will help .
[quote="Alex S"]These helmets are made to withstand collisions of up to 12MPH!!!
The same as just about every bike helmet on the market then, downhill MTB helmets excluded obviously. The safety standard of a bike helmet is to withstand an impact test of 12mph.
I did wonder why 3 of mine have all snapped Is it a stupid question to ask why they dont make them to withstand impacts over speeds of 12mph , like lets say 20-30?
[quote="jon avery"]I did wonder why 3 of mine have all snapped Is it a stupid question to ask why they dont make them to withstand impacts over speeds of 12mph , like lets say 20-30?
Because they are designed to disintegrate, thereby dissipating the impact force and slowing the deceleration of your head. Most RTA brain injuries are the result of the brain moving around inside the skull rather than spilling out over the road. A helmet that could withstand a 30mph impact would offer no protection. Even motorbike helmets are only tested to impacts between 9-16mph.
I thought the european standard "CE" mark indicates that the helmet is "safe" for a slow collision, equivalent to the impact of falling over and hitting your head from standing still.
And i know that the more serious brands like specialized + giro etc conform to the more rigourous snell tests and can therefore be deemed "safer".
If my memory serves me well, specialized's dual density (2D) helmet is designed for higher speed collisions (around the 25-30mph mark)
All depends how they word their descriptions, exactly what they say it will do, and what tests were done. A test being independent doesn't make it a good or valid test.
Snell testing criteria are based on a minimum decelerating effect provided by a helmet in a variety of circumstances and don't provide indication of a "safe maximum collision speed", granted, but their criteria are widely respected as more difficult to "pass".
The european standard CE is the minimum requirement to call a helmet a helmet. If it failed european standard tests it would be called a hat.
Snell differentiates "good" helmets from "bad" helmets based on whether they pass or fail more thorough tests.