Hard Helmets (Explosive! Expletive?) for the Hard Men of Cycling

[Andre Jute]

The stuff inside my elegant leather iPhone case is D30, a military plastic that is flexible enough when at ease but in an impact becomes harder than steel.



http://www.d3o.com/d3o_products/helmet-liner-range/

This stuff's already used in limb protection on bicycles, leg guards and arms guards and suchlike for downhill flyers and other offroaders.

http://www.d3o.com/d3o_products

But I'm just wondering whether there isn't a bicycle helmet application here. You put this stuff on the inside of the helmet, the foam compresses in the normal manner, and even as the helmet is destroyed the layer of impenetrability hardens and stops pointy bits sticking into your brains (yes, we know, but we're being polite!) or even unpleasant gashes and abrasions.

http://www.d3o.com/d3o_products/trust-helmet-liner-system/

Actuallement, if I were in charge of the experimental program, I'd go for pinky-guards first, because it's always my little fingers I break first in any shunt. (Must stop genteelly drinking tea on my bike!)

[jags]

but aren't helmets designed to break on impact bit like formula 1 racing cars.

[il padrone]

Yes, a hard shell does nothing for impact absorption. Our styrofoam hats are designed to compress on impact, a bit different from breaking. Once the shell breaks apart it can do very little to absorb impacts.

[Andre Jute]

A cycle helmet isn't supposed to break. It protects by the foam compacting/deforming/crushing to absorb the impact. It offers zero protection again penetrating elements.

What I'm wonder is whether a helmet with a crush zone of foam on the outside and a layer of D30 on the inside wouldn't  be the best of both worlds, offering both crush deceleration and protection against penetration.

[il padrone]

The thing is, helmets used to have a hard shell. The ancient Bell Biker and MSR both had a shell made from Lexan polycarbonate, the same thing bullet-proof vests and screens are made from. When my MSR had passed it's use-by and had been replaced, I attempted to destroy the shell with a hard attack with a ball-peen hammer. The hammer head simply bounced off at great velocity - gave me a great shock.

The hard shell was dropped from bike helmets because to put it simply, penetration is not the sort of thing which causes severe head injury. A hard shell is very much overkill.

[Andre Jute]

Okay. Bad idea. Thanks for the history lesson: I hadn't realized helmets were once quite that hard-shelled.

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