Raleigh

"Just zis Guy, you know?" <[email hidden]>typed

Quoted message said:

At Sun, 10 Jul 2005 16:21:59 +0100, message
<[email hidden]> was posted by Tilly
<[email hidden]>, including some, all or none of the
following:

Quoted message said:

Quoted message said:

Then it's doubly fortunate that I will have a stock of school helmets
in various sizes.

Quoted message said:

Tch! How can this possibly be a problem? Helmets are *cheap*! They
must be, the BMA Board of Science said so :o)

It's not just size. SHAPE is at least as important when getting a h*lm*t
to fit. My head is nearly impossible to get a secure fit.

A mutant

--
Helen D. Vecht: [email hidden]
Edgware.

Tilly said:

Then it's doubly fortunate that I will have a stock of school helmets
in various sizes.

If you need one that's basically more or less
elongated/spherical/whatever than Exhibit A, that Exhibit B is a
bigger or smaller won't help you much. Square pegs, round holes, etc.

From Brian Walker's article in Cycle:

"Apart from racing cyclists either off or on road, I hardly ever
see a cycle helmet worn properly. The effectiveness of any type of
protective headgear in an accident is influenced to a lagre degree
by the fit on the head and the correct wearing position."

Specialized helmets fit me better than Bells. And so similarly or
otherwise for other people/hat combinations. Just like shoes, the
fact that I use Brand X is no help to someone else, even if they're
the same nominal size as me.

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 [email hidden] http://www.dundee.ac.uk/~pjclinch/

Peter Clinch said:

Tilly said:

Then it's doubly fortunate that I will have a stock of school helmets
in various sizes.

If you need one that's basically more or less
elongated/spherical/whatever than Exhibit A, that Exhibit B is a
bigger or smaller won't help you much. Square pegs, round holes, etc.

From Brian Walker's article in Cycle:

"Apart from racing cyclists either off or on road, I hardly ever
see a cycle helmet worn properly. The effectiveness of any type of
protective headgear in an accident is influenced to a lagre degree
by the fit on the head and the correct wearing position."

Specialized helmets fit me better than Bells. And so similarly or
otherwise for other people/hat combinations. Just like shoes, the
fact that I use Brand X is no help to someone else, even if they're
the same nominal size as me.

My helmet has internal adjustments that will hold to 2/3 of the head
around the rim. The top of the head touches the helmet. It won't
wobble on my head. This is the same with the most helmets I fit to
children, occasionally the helmet is too large to fit snugly to the
head and occasionally it is too small.

My climbing helmet is a different design altogether, but has the same
principle of adjustability, so I can't think the problem is specific
to cycling. Oh... and I've fitted helmets to classes of 30 primary
school aged children for rock climbing and caving and never had a fit
problem that couldn't be fixed.

I agree that most cycling helmets are not correctly fitted, but it is
only a matter of seconds to adjust them so they fit them correctly.
And they are not like shoes as they have more adjustments than a shoe
lace. Perhaps sandals with a heel adjustment would be a closer
comparison.

Tilly said:

My climbing helmet is a different design altogether, but has the same
principle of adjustability, so I can't think the problem is specific
to cycling.

My climbing and cycling helmets are completely different. But OTOH
they're designed for different jobs, so it's hardly surprising.
In my climbing lid (an Ecrin Rock) it is the internal, separate
cradle you're adjusting, and the helmet sits *away* from the head
on the foundation of the cradle. Resizing a flexible cradle, much
of which conforms to the wearer because it is flexible, is much
easier than reshaping a rigid chunk of polystyrene. Climbing
helmets sit much further above the head than cycle helmets and the
lid shell itself never touches the head of the wearer (possibly
exceptions for the like of Petzl Meteors, which are based on cycle
helmets, though I've never examined one close up so can't be sure).
Cycle helmets rely on the shell being flush against the head to
maximise the spread of impact force across the widest possible
area. If they're not, they won't work properly. Climbing helmets
use the airspace to their advantage, but they can only do that
thanks to a much less brittle shell which will retain integrity
while passing on force to the cradle, and more airspace. So
they're not a good comparison to cycle helmets at all.

Quoted message said:

Oh... and I've fitted helmets to classes of 30 primary
school aged children for rock climbing and caving and never had a fit
problem that couldn't be fixed.

And the above tells you why that is (I go caving too, and have a
caving helmet too, again with a different adjustment, more similar
to the climbing helmet but not as bombproof as the main name of the
game is constant abrasion rather than traumatic shock, so still an
apples vs. oranges comparison).

Quoted message said:

I agree that most cycling helmets are not correctly fitted, but it is
only a matter of seconds to adjust them so they fit them correctly.

If it is the wrong basic shape then no amount of fiddling with the
straps is going to alter that. It is the rigid and unadjustable
shell that needs to conform closely to the wearers head for the
impact spreading and deformation under load by which a cycle helmet
works in an accident to work optimally.

Quoted message said:

And they are not like shoes as they have more adjustments than a shoe
lace. Perhaps sandals with a heel adjustment would be a closer
comparison.

And again it will illustrate that if the basic shape is
fundamentally wrong then you're *not* going to get a good fit. I
don't like Merrel sandals because I find the footbed is too narrow
for me. Any amount of fiddling with the straps doesn't change
that, so I wear Tevas by preference. Roos wears Merrels, not
getting on with Tevas, for the equal and opposite reasons. But
rather than a foot which is a bit less comfy, you get a helmet
which can't be trusted to perform to the expected standards.

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 [email hidden] http://www.dundee.ac.uk/~pjclinch/

Tilly said:

My helmet has internal adjustments that will hold to 2/3 of the head
around the rim. The top of the head touches the helmet. It won't
wobble on my head. This is the same with the most helmets I fit to
children, occasionally the helmet is too large to fit snugly to the
head and occasionally it is too small.

Quoted message said:

I agree that most cycling helmets are not correctly fitted, but it is
only a matter of seconds to adjust them so they fit them correctly.

You must be extremely lucky.
I estimate that about 80% of the helmets I come across are badly fitting
- they usually can be pushed to the back of the head.
Quite often this is with new helmets that *should* have been fitted by
the supplier. IME few helmets have good internal adjustment - I am
surprised you say "most" as the majority I see are cheap ones that only
have padding and strap adjustability.
And of course wiith these the wearer *never* brings along the
alternative pads.

I agree completely with Peter that helmets should match to the shape of
the head and that the wrong shape helmet will never fit correctly.
Unfortunately too few cyclists/parents have the helmet properly fitted
when they purchase them - usually only possible at a good LBS.
Instead they buy from such experts as Woolworths, Argos, Halfords or
even mail order.

Getting helmets to fit is, IMO, one of teh most frustrating aspects of cycle-instruction.

John B

JohnB said:

Getting helmets to fit is, IMO, one of teh most frustrating aspects of cycle-instruction.

I said that most helmets are not correctly fitted. Your implied
figure of 20% is optimistic.

However, most helmets can be adjusted to fit correctly within a few
seconds. It's a tedious job, and with two instructors it takes five
to ten minutes of the first lesson with a group of 12.

Tilly said:

However, most helmets can be adjusted to fit correctly within a few
seconds.

No amount of fiddling with straps will change the basic shape of
the shell, because the shell is a fixed rigid form and so is the
head. The shell should conform to the shape of the wearer's head
cloesly for the helmet to work properly according to specification.
It is a basic requirement that the head be more or less up
against the shell throughout the volume of the helmet, and since
you can't change the shape of the shell or the child's head you are
stuck as far as adjustment goes. If the shell is basically the
wrong shape for the child's head then it *cannot* be adjusted to
fit correctly: correct fitting requires conformance of the shell to
the head, not simply optimal adjustment of the strapping.

That any given cycle helmet can't be assumed to work optimally on
any given head is an important lesson to learn for anyone that will
be wearing one.

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 [email hidden] http://www.dundee.ac.uk/~pjclinch/

Tilly said:

JohnB said:

Getting helmets to fit is, IMO, one of teh most frustrating aspects of cycle-instruction.

I said that most helmets are not correctly fitted. Your implied
figure of 20% is optimistic.

That's around what I find.
One in five have them fitted adequately.

Quoted message said:

However, most helmets can be adjusted to fit correctly within a few
seconds.

That's where we differ then.
I find that many are just not suitable for the shape of the rider's head
- something which would have been avoided had they taken expert advice
at the outset.
But FWIW I do find I have less problems with the skateboard style helmets.

Quoted message said:

It's a tedious job

Sure is :-(
Too many follow the example of the reading helmet expert:
http://freespace.virgin.net/jpb.design/helmetadvice.html

John B

in message said:

Sure is :-(
Too many follow the example of the reading helmet expert:
http://freespace.virgin.net/jpb.design/helmetadvice.html

Sure is :-(
Too many follow the example of the reading helmet expert:
http://freespace.virgin.net/jpb.design/helmetadvice.html

"In not more that ten words what should this famous 'cycling'
personality do to improve road safety?"

Head-butt a speeding truck wearing her protective polystyrene beanie.

--
[email hidden] (Simon Brooke) http://www.jasmine.org.uk/~simon/

;; L'etat c'est moi -- Louis XVI
;; I... we... the Government -- Tony Blair

On Fri, 08 Jul 2005 21:33:59 +0100, Peewiglet <[email hidden]>

Quoted message said:

My little bike is a hybrid and I think it must be a blokes' style as I
have to swing my leg up to get on.

Yes, from what I remember of it, it *is* a "man's bike". I've always
had a "woman's bike" and feel happier with that style - probably
because that is what I am used to.

Judith

Judith said:

On Fri, 08 Jul 2005 21:33:59 +0100, Peewiglet <[email hidden]>
wrote:

Quoted message said:

Quoted message said:

My little bike is a hybrid and I think it must be a blokes' style as I
have to swing my leg up to get on.

Quoted message said:

Yes, from what I remember of it, it *is* a "man's bike". I've always
had a "woman's bike" and feel happier with that style - probably
because that is what I am used to.

Worth noting that there's more to it than whether the crossbar is low or
not, though traditionally that *was* the only difference. The main
difference in a women's specific frame should be the reach, which tends
to be proportionately shorter in women than men.
http://www.cannondale.com/bikes/05/cusa/cats/FEM.html shows you a range
of very nice WSD bikes with high crossbars.

A high bar makes for a stiffer frame than a step-through, which can make
a significantly useful difference in some applications, but for just
pootling about it's frankly a non-issue and it just makes it harder to
get on and off. One of the reasons I like the Brompton for an urban
hack is the easy stepover.
Where serious engineering is thrown at it you can get some very stiff
frames with low stepovers, Moultons being a classic example (see
http://www.alexmoulton.co.uk/).

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 [email hidden] http://www.dundee.ac.uk/~pjclinch/

JohnB said:

Quoted message said:

However, most helmets can be adjusted to fit correctly within a few
seconds.

That's where we differ then.
I find that many are just not suitable for the shape of the rider's head
- something which would have been avoided had they taken expert advice
at the outset.
But FWIW I do find I have less problems with the skateboard style helmets.

After all this discussion I looked at the helmets of my eight trainees
today with renewed interest.

I checked them all again to see how well they fitted on the head. I
found them all to be a good fit with much of the top and front of the
helmet in contact with the head. At the back there were gaps, but the
helmets' internal adjustment fitted correctly, holding the helmet in
place without much movement. I needed to adjust a few of the straps
which had loosened over the week, but that is to be expected.

Am I overlooking something? Have I just been lucky? Do I have lower
standards of fit than I should?

Tilly said:

I checked them all again to see how well they fitted on the head. I
found them all to be a good fit with much of the top and front of the
helmet in contact with the head. At the back there were gaps, but the
helmets' internal adjustment fitted correctly, holding the helmet in
place without much movement. I needed to adjust a few of the straps
which had loosened over the week, but that is to be expected.

Am I overlooking something? Have I just been lucky? Do I have lower
standards of fit than I should?

Helmets are made for typical heads, and they typically fit a lot of
heads as a result. But not all of them. Different manufacturers use
slightly different "standard" head shapes, so some brands fit some
people better than others.

However, "internal adjustment" is *not* actually adjusting the shape of
the shell, which is what should be fitting against the head. If the
shell itself is not close up against the head then the load spreading
functionality of the helmet won't work as designed. In a climbing
helmet the load spreading is done by the flexible internal cradle, but
it's the shell itself that does this in a cycling helmet.

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 [email hidden] http://www.dundee.ac.uk/~pjclinch/

Tilly said:

JohnB said:

Quoted message said:

However, most helmets can be adjusted to fit correctly within a few
seconds.

That's where we differ then.
I find that many are just not suitable for the shape of the rider's head
- something which would have been avoided had they taken expert advice
at the outset.
But FWIW I do find I have less problems with the skateboard style helmets.

After all this discussion I looked at the helmets of my eight trainees
today with renewed interest.

I checked them all again to see how well they fitted on the head. I
found them all to be a good fit with much of the top and front of the
helmet in contact with the head. At the back there were gaps, but the
helmets' internal adjustment fitted correctly, holding the helmet in
place without much movement. I needed to adjust a few of the straps
which had loosened over the week, but that is to be expected.

Am I overlooking something? Have I just been lucky? Do I have lower
standards of fit than I should?

Without doing a direct exercise using the same group, those questions
are difficult to answer.
I do find adjusting straps alone to be fairly quick, but it is the fit
of the helmet to the head shape which is most problematical as this
often requires adjustment to padding - not always available (for which
read 'never'😉.
Of course it is better that helmet shape and head shape are correctly
matched in the first place, but if they are not then any result will
always be some degree of bodge.

On another tack, two of my five trainees the other night had those awful
full face hemets :-(

Best adjustment in those cases is complete removal ;-)

John B

JohnB said:

I do find adjusting straps alone to be fairly quick, but it is the fit
of the helmet to the head shape which is most problematical as this
often requires adjustment to padding - not always available (for which
read 'never'😉.

But typically the padding you get is lightweight open cell foam, which
is basically useless from a load spreading point of view so anything
much beyond the minimum amount for comfort is tending you towards a
cosmetic exercise in any case.

Perhaps another reason why helmets aren't nearly as much use in reality
as we're assured they must be... :-(

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 [email hidden] http://www.dundee.ac.uk/~pjclinch/

Peter Clinch said:

JohnB said:

I do find adjusting straps alone to be fairly quick, but it is the fit
of the helmet to the head shape which is most problematical as this
often requires adjustment to padding - not always available (for which
read 'never'😉.

But typically the padding you get is lightweight open cell foam, which
is basically useless from a load spreading point of view so anything
much beyond the minimum amount for comfort is tending you towards a
cosmetic exercise in any case.

I know, I know, I KNOW.
Heads should ideally be dipped in plaster to create a mould.

But if mummy or teacher won't let child undertake training unless they
are wearing a helmet, some padding is better than not riding at all.

Quoted message said:

Perhaps another reason why helmets aren't nearly as much use in reality
as we're assured they must be... :-(

You are implying there Peter, that they have *some* use.

Do be careful ;-)

John B

JohnB said:

some padding is better than not riding at all.

For the individual concerned, perhaps.

For the population of cyclists as a whole, perhaps not.

R.

JohnB said:

But if mummy or teacher won't let child undertake training unless they
are wearing a helmet, some padding is better than not riding at all.

Indeed, though in Tilly's case she's Clued In enough not to resort to
that sort of hysteria, but apparently didn't know the extent to which
correct fitting is dependent on the shell/head fit rather than
straps/head fit, so I figured possibly useful information.

Since it's the case that helmets can't necessarily be made optimally
fitting by just careful fiddling with the straps, as had apparently been
considered the case, the money earmarked for lids might be spent
differently, perhaps either on a greater cross section of styles as well
as sizes, or (preferably IMHO) some alternative sizes and/or styles of
cycles, while parents who insist on their moppets having hats given as
much information as they can have poured into them on selecting a
personal model optimised for their child for the best possible safety.

IMHO safety equipment is best left to people who will have its *sole*
use: IME a lot more care gets taken of it that way, and a lot more care
goes into its selection. And that's not just because of safety cares,
it's people just caring more for their own stuff. I've seen shameful
treatment of club climbing ropes people are relying on to keep them
alive while the very same people will be very careful of their own.
Hire or loan kit is regularly mistreated far more than personal kit, and
that's part of why it tends not to be so good.

Quoted message said:

You are implying there Peter, that they have *some* use.

Do be careful ;-)

"some padding is better than not riding at all" ... ;-/

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 [email hidden] http://www.dundee.ac.uk/~pjclinch/

Richard said:

JohnB wrote:

Quoted message said:

Quoted message said:

some padding is better than not riding at all.

Quoted message said:

For the individual concerned, perhaps.

For the population of cyclists as a whole, perhaps not.

But perhaps yes... more riders on the roads are known to be a Good Thing
for the cycling population at large.

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 [email hidden] http://www.dundee.ac.uk/~pjclinch/

Peter Clinch said:

Richard said:

JohnB wrote:

Quoted message said:

Quoted message said:

some padding is better than not riding at all.

Quoted message said:

For the individual concerned, perhaps.

For the population of cyclists as a whole, perhaps not.

But perhaps yes... more riders on the roads are known to be a Good Thing
for the cycling population at large.

Indeedy, but more % of riders wearing helmets -> more implication that
cycling is dangerous -> less cyclists -> more danger for those that
remain. 8-)

It's a tricky business.

R.