The CycleChat Helmet Debate Thread

[Justinslow]

Where I ride off road I am guaranteed to hit some branches and stems. A bleeding scalp can spoil a ride. A lid has a handy strap to keep it on unlike my preferred headgear.

As to cycling being hard work... are the laws of physics different in Copenhagen? Your type of cycling might be hard work but we don't all find it so. I can ride for miles expending nor more energy or effort than I would walking. Every ride isn't a faux race.

Yes but has Denmark got as many fat lazy bar stewards living there?

 

[Justinslow]

Where I ride off road I am guaranteed to hit some branches and stems. A bleeding scalp can spoil a ride. A lid has a handy strap to keep it on unlike my preferred headgear.

Don't be ashamed, it's doing its job isn't it!

 

[classic33]

http://www.explainthatstuff.com/how-bicycle-helmets-work.html
How does a bicycle helmet work?

At first sight, a cycle helmet looks much like any other hat, but look more closely and you'll see a lot more thought—and science—has gone into the design. A typical helmet has two main parts: a hard outer shell and a soft inner liner. The hard shell is designed to spread the force of an impact over a broader area so your skull is less likely to fracture, while the soft liner is meant to squeeze inward and absorb the impactenergy, so less of it is transmitted to your head.

Bicycle helmets are a good example of how the right material can make all the difference to how well something does its job. Shells are typically made of composite materials like fiberglass or lightweight carbon fiber, or very hard plastics such as polycarbonate or ABS. Liners are usually about 20cm (0.8 inches) thick and made of two layers of foam: a soft, bouncy layer that absorbs small bashes and bumps and a stiff layer that permanently deforms to absorb very hard impacts. Some helmets are now incorporating energy-absorbing plastics like D3O® that are soft in normal use but harden instantly the moment you hit them, but most still use cheaper and simpler materials like expanded polystyrene (EPS) or expanded polypropylene (EPP).

Photo: How a helmet saves your life: When you bump your head, the hard outer shell (black) spreads the impact over a wide area. The whole of the soft inner liner (orange) then absorbs the energy evenly so (hopefully) there's minimal damage to your head. Without the helmet, the entire impact would be concentrated on a tiny part of your head, very likely fracturing your skull and quite possibly damaging your brain too.

 

[Justinslow]

May have been posted before?
Maybe the uk really does have awful drivers?

http://www.theguardian.com/environment/bike-blog/2015/jun/11/why-cycling-in-the-uk-is-so-scary

 

[classic33]

I know that there are a host of variables, but generally speaking, is there any real world way to give an idea of what a 13 mph impact equates to?

For example, (and I know it's far from the same, but could be a branch on a mountain bike) things like, how fast was the teachers cane going when it hit my hand, or how fast am I going if I trip and fall to the floor?

"Dynamics of falls and blows
It has been said that packed earth can still cause 200G deceleration after a 1.2 metre fall.38 This can be calculated from force/compression data, measured for a given object and ground type by a compression dynamometer. As an example, the following figures were calculated from actual data obtained for a 1.5 kg, 15 cm sphere (equivalent of a 12 kg toddler’s head) indenting packed earth, for a fall of 1.5 metres: velocity, 5.4 m/sec at impact; kinetic energy, 21.9 Joules at impact; deceleration, mean 81 G, peak 238 G; force, peak 3500 Newtons; distance indented, 18.6 mm; stopping time 4.8 msec, assuming all kinetic energy is expended as work of compression (C Wainwright, personal communication). These figures are for the skull—they cannot be calculated for the brain. Deceleration is greater and indentation less for smaller objects, for a harder surface, and if (as must be the case) some of the kinetic energy on impact is absorbed into the head as deformational strain in the skull39 or brain. Deceleration is greater for a higher fall—doubling the fall less than doubles velocity but more than doubles peak deceleration. Kinetic energy of a falling object is proportional to mass and to distance fallen, and independent of ground type. At impact some of this energy is dissipated as work of compressing the ground as the object decelerates. Soft ground may be less injurious than hard, not necessarily because acceleration is less (it operates over a longer time) but because more kinetic energy is absorbed by the surface, less by the head."
http://adc.bmj.com/content/76/5/393.full

 

[ufkacbln]

A bleeding scalp is fairly minor to the injuries that can be caused by a branch catching in the vents!

I was involved in a nasty injury some years ago where exactly this happened

There is also the possibility of strangulation (and even death) in a similar manner as has happened with helmets getting caught on play equipment

Once again, make your own choice, but do be aware of the reality that once again helmets are NOT as beneficial as some would have us believe

 

[theclaud]

At first sight, a cycle helmet looks much like any other hat

There speaks someone in need of a new milliner.

 

[classic33]

There speaks someone in need of a new milliner.

Follow the link and read a bit further down though.

 

[Dan B]

Follow the link and read a bit further down though.

New milliner and a new neurologist?

 

[ufkacbln]

I could have done with a walking helmet this morning. It's been raining here in Granada and the pavements (mainly made of marble) are lethal. I almost went a-over-t a number of times, despite wearing shoes with good soles.

I was more at risk of a head injury than someone on a bike...

Wearing a Tilley with its "proven" life saving abilities would be an appropriate solution?

 

[ufkacbln]

I was wearing my Tilley... an Outback.

Superb taste and refinement!

Today I am off to Worcester for a week on the Canals I will be wearing my ancient and trusty LT3 on the boat and the lighter LT5 when in the pub.

You never know when you will need the protection that a Tilley offers....


They even do one with vents now!

 

[Justinslow]

I could have done with a walking helmet this morning. It's been raining here in Granada and the pavements (mainly made of marble) are lethal. I almost went a-over-t a number of times, despite wearing shoes with good soles.

I was more at risk of a head injury than someone on a bike...

Or avoid walking on "lethal" wet slippery surfaces.........,

 

[ufkacbln]

Or avoid walking on "lethal" wet slippery surfaces.........,

But what about a high speed sole failure?

 

[Justinslow]

Have you ever been to Granada? Your rather childish post would suggest not...

No I haven't, sorry if it came across as childish, I'm just taking @Cunobelin's lead, try to avoid putting yourself in harms way, if that's an impossibility then resort to safety measures?

 

[Justinslow]

But what about a high speed sole failure?

Yes there is that I suppose, delamination.