Cycle helmet broken in fall

This sub-forum all discussions about this "lively" subject. All topics that are substantially about helmets will be moved here, if not placed here correctly in the first place.
Posts: 3382
Joined: 23 Feb 2010, 4:10pm

Re: Cycle helmet broken in fall

Postby beardy » 22 Dec 2014, 11:33am

The helmet failed to work in the way that it is supposed to do, the ambulance service glorify it because the failure looks spectacular and the rider will probably replace it with the same model because "it worked so well".

The way it failed looks rather like one of those fake ones.


Steady rider
Posts: 2189
Joined: 4 Jan 2009, 4:31pm

Re: Cycle helmet broken in fall

Postby Steady rider » 22 Dec 2014, 7:47pm

To the cyclist this seems a simple case of protection but a number of issues arise. The speed was low yet he lost control.
The actual junction with the cobbles can you say where this is? It may be more dangerous than needs be.

Riding over cobbles the head may be subject to about 1-3g forces according to some research. The helmet may weigh say 250grams, so may give off forces equivalent to more than 0.7 kg at a time of braking hard and leaning, so will probably increase the risk of falling. CT scan X rays both may incur risk, without the fall these may have been avoided.

Some degree of concussion occurred it seems. So probably the impact did affect the brain. The impact location above ear, the widest part of the skull, probably about 75mm from centre line of head, add helmet 100 mm probably, 33% increase. The risk increase from perhaps behaviour, fall off rate, contact rate - combined perhaps 50%+

On the one hand, broken helmet that save me approach and on the other hand would I have fallen or been riding in the same way without a helmet? yes he may have been but would head contact have been made? Other injuries also resulted
that could have been serious.

The above is taking a rather negative view and lets hope another fall is a long way off, if at all.


ps Table 1 comparing m/cyc vs car occ. 26%, 34%, 50%, compared to car occupants, m/cyc safety reduced
1970 m.cyc 3880 million km, 1980 7700 million km
1970 approx. 100 billion miles for cars, 1980 approx. 135 billion miles
Accounting for distance, 26% ratio in 1970 increased to 39% by 1980 but figures need checking ... ummary.pdf