Thanks - "Be Bright - Wear White" vs' "Fight Back - Wear Black"

Thanks for all of the observations. Here are a few of my own:

1 - It's far better to be lit up at night - and ride with the mentality that
you're in matt black and everyone driving a car has a guide dog in the back.

2 - On unlit lanes, you need a bright front light. In addition to
illuminating the road/obstacles ahead, it forces oncoming drivers to dip
their headlights.

3 - I've read cyclecraft and after lots of experimentation, came to the
conclusion that if you're too far out, you get a lot of abuse from drivers.
I agree that being in the left tyre track is the best position for 3
reasons:
a) You're in the line of sight of drivers - without appearing to be
deliberately hogging the road (important at rush hour).
b) It forces "use of brain" overtaking in a way that being too far over to
the left doesn't.
c) There is much less road debris as it tends to get knocked aside by motor
vehicles . I once clipped a house brick in the middle of the road which
gave me the SHIVERS.

4 - Juggling in the dark is hard.


On a similar point to 1 above, I firmly believe that it's crucial to wear a
helmet - and ride with the mentality that your brain is encased in an egg
shell.

A testament to this is that an oncoming SMIDSY* WVM once pulled across me to
turn right and I went into the side of him at around 30 mph (I was going
down hill at the time). I didn't even have a chance to put my hands out
and I ploughed into him head first - resulting in a cracked helmet but an
intact skull. I am convinced that things would have been quite different
had I not conceded to my wife's powers of persuasion and started wearing a
helmet.

*I'm not really sure if he was a SMIDSY because he drove off in a cloud of
diesel exhaust fumes.

Drinky wrote:
..


On a similar point to 1 above, I firmly believe that it's crucial to wear a
helmet - and ride with the mentality that your brain is encased in an egg
shell.

I don't.

Drinky wrote:

On a similar point to 1 above, I firmly believe that it's crucial to wear a
helmet - and ride with the mentality that your brain is encased in an egg
shell.

If you're wearing a lid, ride with the mentality that it will do what
they have a proven track record of doing: nothing to save serious
injuries. There is /no/ compelling evidence that they'll save you from
anything more than a graze, and though a graze isn't any fun it's by no
means "crucial" that you avoid them at all costs.

A testament to this is that an oncoming SMIDSY* WVM once pulled
across me to
turn right and I went into the side of him at around 30 mph (I was going
down hill at the time). I didn't even have a chance to put my hands out
and I ploughed into him head first - resulting in a cracked helmet but an
intact skull. I am convinced that things would have been quite different
had I not conceded to my wife's powers of persuasion and started wearing a
helmet.

If your helmet cracked then it failed. It is quite unlikely your skull
would have cracked, skulls are very hard and the sides of white vans are
actually quite ductile (broad, unstressed sheets of thin, soft metal
which dent easily with nothing behind them to bring you to a sudden
stop) and in impacts will undergo the sort of deformation without
breaking that your helmet /should/ have done if it had worked properly
to absorb the blow. It wouldn't have been any fun, but it's most
unlikely you'd have been killed and very possibly not much injured
beyond a bit dazed. I'm afraid this looks like another "a helmet saved
my life!" anecdote which if a control was possible would turn out not to
be quite the benefit you've assumed.

Pete.
--
Peter Clinch Medical Physics IT Officer
Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
net http://www.dundee.ac.uk/~pjclinch/

Response to Peter Clinch:
I'm afraid this looks like another "a helmet saved
my life!" anecdote which if a control was possible would turn out not to
be quite the benefit you've assumed.


And "brain enclosed in eggshell" perception or not, I found myself
wondering if the PP would have been riding downhill at 30mph at all if he
hadn't been wearing a lid. I hope I'm under no illusions as to the lack
of benefit/dangers of helmets, but on the rare occasions I wear one, I
still wonder if I'm guilty of a degree of risk compensation.

--
Mark, UK.
We hope to hear him swear, we love to hear him squeak,
We like to see him biting fingers in his horny beak.

Peter Clinch wrote:
If your helmet cracked then it failed. It is quite unlikely your skull
would have cracked, skulls are very hard and the sides of white vans are
actually quite ductile (broad, unstressed sheets of thin, soft metal
which dent easily with nothing behind them to bring you to a sudden
stop)

Indeed. confession time In my callow and reckless youth I was cycling
rather too fast around a corner and found a white van (one of the little
ones based on a car) parked there where there hadn't been before :-).
Naturally I stared at it in terror and therefore hit it :-) but had the
presence of instinct to manage to skid the bike sideways so I hit it
with me sideways on. There was a godalmighty BANG.

Once I'd dusted myself off and figured that none of me was broken, I
inspected the van. There was a HUGE dent in the side. So wearing my
most sheepish expression I knocked on the door of the house without
which it was parked. The owner came out, listening to me apologise, and
was inspecting the damage - when there was another, slightly less huge,
BANG, and the entire side popped out again to resume its original shape.
He looked at me, I looked at him, and he said, "Well, that's alright
then. Forget about it, mate" and wandered back inside.

R.

Drinky wrote:
Thanks for all of the observations. Here are a few of my own:

1 - It's far better to be lit up at night - and ride with the mentality that
you're in matt black and everyone driving a car has a guide dog in the back.

More or less with you so far. Unfortunately there are so many lights of
all sorts in (sub)urban environments that the relatively feeble ones
found on normally equipped bikes do not necessarily stand out.

2 - On unlit lanes, you need a bright front light. In addition to
illuminating the road/obstacles ahead, it forces oncoming drivers to dip
their headlights.

As the author of the post that inspired this thread, I ought to point
out it had nothing to do with riding on unlit roads where there is a
need to illuminate your route. However, I am amused by your notion that
anything the cyclist does forces a driver to do anything. Au contraire
to your supposition, I have known car drivers switch from dip to full
beam upon getting a glimpse of an oncoming cyclist. Perhaps they were
curious to find out what was approaching. Perhaps they thought this a
way of communicating "you have only one light working" to the thing they
had glimpsed. Perhaps they just hate cyclists.

3 - I've read cyclecraft and after lots of experimentation, came to the
conclusion that if you're too far out, you get a lot of abuse from drivers.
I agree that being in the left tyre track is the best position for 3
reasons:
a) You're in the line of sight of drivers - without appearing to be
deliberately hogging the road (important at rush hour).
b) It forces "use of brain" overtaking in a way that being too far over to
the left doesn't.
c) There is much less road debris as it tends to get knocked aside by motor
vehicles . I once clipped a house brick in the middle of the road which
gave me the SHIVERS.

Position is indeed crucial.

4 - Juggling in the dark is hard.


On a similar point to 1 above, I firmly believe that it's crucial to wear a
helmet - and ride with the mentality that your brain is encased in an egg
shell.

Could not agree less.

A testament to this is that an oncoming SMIDSY* WVM once pulled across me to
turn right and I went into the side of him at around 30 mph (I was going
down hill at the time). I didn't even have a chance to put my hands out
and I ploughed into him head first - resulting in a cracked helmet but an
intact skull. I am convinced that things would have been quite different
had I not conceded to my wife's powers of persuasion and started wearing a
helmet.

Anecdotes are not evidence or a testimony to the helmet's efficacy and
give no worthwhile indication of what would have happened otherwise.
Would you be impressed by one of my (many) stories about how I went on a
ride without a helmet and did not hit my head off anything at all? Why not?

--
Joe * If I cannot be free I'll be cheap

Peter Clinch wrote:
Drinky wrote:

On a similar point to 1 above, I firmly believe that it's crucial to
wear a helmet - and ride with the mentality that your brain is encased
in an egg shell.


If you're wearing a lid, ride with the mentality that it will do what
they have a proven track record of doing: nothing to save serious
injuries. There is /no/ compelling evidence that they'll save you from
anything more than a graze, and though a graze isn't any fun it's by no
means "crucial" that you avoid them at all costs.

A testament to this is that an oncoming SMIDSY* WVM once pulled
across me to

turn right and I went into the side of him at around 30 mph (I was
going down hill at the time). I didn't even have a chance to put my
hands out and I ploughed into him head first - resulting in a cracked
helmet but an intact skull. I am convinced that things would have
been quite different had I not conceded to my wife's powers of
persuasion and started wearing a helmet.


If your helmet cracked then it failed. It is quite unlikely your skull
would have cracked, skulls are very hard and the sides of white vans are
actually quite ductile (broad, unstressed sheets of thin, soft metal
which dent easily with nothing behind them to bring you to a sudden
stop) and in impacts will undergo the sort of deformation without
breaking that your helmet /should/ have done if it had worked properly
to absorb the blow. It wouldn't have been any fun, but it's most
unlikely you'd have been killed and very possibly not much injured
beyond a bit dazed. I'm afraid this looks like another "a helmet saved
my life!" anecdote which if a control was possible would turn out not to
be quite the benefit you've assumed.

Pete.


SMIDSY
No can't get this one? (small minded idiot driving...?)

skulls are very hard and the sides of white vans are
actually quite ductile (broad...

I thought skulls were comparativly weak requiring only about 8lbs per sq
inch to break. Thats what I was taught as a RM.

Sniper8052

On Tue, 23 Nov 2004 14:28:37 GMT, "Sniper8052(L96A1)"
wrote:

SMIDSY
No can't get this one? (small minded idiot driving...?)

"Sorry, mate, I didn't see you"

Guy
--
May contain traces of irony. Contents liable to settle after posting.
http://www.chapmancentral.co.uk

88% of helmet statistics are made up, 65% of them at Washington University

On 23/11/04 2:28 pm, in article
, "Sniper8052(L96A1)"
wrote:

SMIDSY
No can't get this one? (small minded idiot driving...?)

Sorry Mate I didn't See you.


skulls are very hard and the sides of white vans are
actually quite ductile (broad...

I thought skulls were comparativly weak requiring only about 8lbs per sq
inch to break. Thats what I was taught as a RM.

RM? I'd be most surprised if a skull would break at 8lb per sq in.

So far I have found the following:

Young's modulus of bone varies from 1.8x10e10 N/m2 fro compact bone to 7.6 x
10e7 for trabecular bone.

Tensile strength is 1.2x10e8 N/m2

Compressive strength is 1.7x10e10 (compact) 2.2x10e6 (Trabecular).

I suppose it does matter where you put your 8lb/sq in but a quick
calculation indicates this is equivalent to 2.8x10e5, at least an order of
magnitude below the tensile strength of the bone.

...d

Sniper8052(L96A1) wrote:

I thought skulls were comparativly weak requiring only about 8lbs per sq
inch to break. Thats what I was taught as a RM.

Comparitive to what? If they were too weak to be useful fractured
skulls would be commonplace, but though bumps and scrapes happen a lot
fractures don't strike me as /that/ common. Especially if the impact is
against a broad sheet to spread the load that also deforms and conforms
as you strike it.

Pete.
--
Peter Clinch Medical Physics IT Officer
Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
net http://www.dundee.ac.uk/~pjclinch/