Tied and soldered spokes.

On 20 Nov, 18:38, Ian Smith wrote:
On Fri, 20 Nov 2009 17:22:32 +0000, Tom Anderson wrote:
*On Thu, 19 Nov 2009, Marc wrote:

thirty-six wrote:
Tying and soldering the spokes will diminish the possibility of a
radial buckle in a lighweight rim when heavily loaded.

A desperate troll for attention.

*Played for, and got.

Out of interest, however, has anyone ever seen a purely radial buckle
on a bicycle wheel?

If you find yourself a 400g shallow section rim I can give you a
description of horw to perform a radial buckle when 'building', for
that is how i managed to get mine. It takes a bit of effort to get it
this wrong, but actually doing it this bad was enlightening to me.

On Nov 21, 3:38*am, Ian Smith wrote:
On Fri, 20 Nov 2009 17:22:32 +0000, Tom Anderson wrote:
*On Thu, 19 Nov 2009, Marc wrote:

thirty-six wrote:
Tying and soldering the spokes will diminish the possibility of a
radial buckle in a lighweight rim when heavily loaded.

A desperate troll for attention.

*Played for, and got.

Out of interest, however, has anyone ever seen a purely radial buckle
on a bicycle wheel?

I've dented a rim wall (think severe pinch flat territory). Does that
count?

James

On Fri, 20 Nov, wrote:
On Nov 21, 3:38*am, Ian Smith wrote:

Out of interest, however, has anyone ever seen a purely radial
buckle on a bicycle wheel?

I've dented a rim wall (think severe pinch flat territory). Does
that count?

I don't think so. In fact, it would tend to demonstrate the case that
they don't happen - you can hit the rim hard enough to cause plastic
material failure and no radial buckle occurred.

But wait - did you have tied-and-soldered spokes?
Perhaps that prevented it becoming a radial buckle?

regards, Ian SMith
--
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Ian Smith wrote:
On Fri, 20 Nov, wrote:
On Nov 21, 3:38 am, Ian Smith wrote:
Out of interest, however, has anyone ever seen a purely radial
buckle on a bicycle wheel?
I've dented a rim wall (think severe pinch flat territory). Does
that count?

I don't think so. In fact, it would tend to demonstrate the case that
they don't happen - you can hit the rim hard enough to cause plastic
material failure and no radial buckle occurred.


Like James, I've dented a rim wall but without buckling the rim as a
whole - I have seen a radial buckle, but in a motor cycle wheel. I
reckon it is possible to radial buckle a wheel but you have to hit it
very hard indeed. The other thing with a pedal cycle wheel is that to
get a purely radial buckle you'd not only have to hit it very hard, but
also dead square, otherwise it will buckle laterally as well. Then you
could argue for days about whether that counts as a radial buckle.

--
Andrew

Ian Smith wrote:
On Fri, 20 Nov, wrote:
On Nov 21, 3:38 am, Ian Smith wrote:
Out of interest, however, has anyone ever seen a purely radial
buckle on a bicycle wheel?
I've dented a rim wall (think severe pinch flat territory). Does
that count?

I don't think so. In fact, it would tend to demonstrate the case that
they don't happen - you can hit the rim hard enough to cause plastic
material failure and no radial buckle occurred.


Like James, I've dented a rim wall but without buckling the rim as a
whole - I have seen a radial buckle, but in a motor cycle wheel. I
reckon it is possible to radial buckle a wheel but you have to hit it
very hard indeed. The other thing with a pedal cycle wheel is that to
get a purely radial buckle you'd not only have to hit it very hard, but
also dead square, otherwise it will buckle laterally as well. Then you
could argue for days about whether that counts as a radial buckle.

--
Andrew

On 21 Nov, 20:16, Naqerj wrote:
Ian Smith wrote:
On Fri, 20 Nov, wrote:
*On Nov 21, 3:38 am, Ian Smith wrote:
Out of interest, however, has anyone ever seen a purely radial
buckle on a bicycle wheel?
*I've dented a rim wall (think severe pinch flat territory). Does
*that count?

I don't think so. *In fact, it would tend to demonstrate the case that
they don't happen - you can hit the rim hard enough to cause plastic
material failure and no radial buckle occurred.

Like James, I've dented a rim wall but without buckling the rim as a
whole - I have seen a radial buckle, but in a motor cycle wheel. *I
reckon it is possible to radial buckle a wheel but you have to hit it
very hard indeed. *The other thing with a pedal cycle wheel is that to
get a purely radial buckle you'd not only have to hit it very hard, but
also dead square, otherwise it will buckle laterally as well. *Then you
could argue for days about whether that counts as a radial buckle.

I'm guessing this wasn't a motocross wheel which had the crossings
tied and soldered, because they do it so as not to collapse wheels.
More likely the trailing and leading spokes dont touch so the wheel is
unable to benefit from the locking together of spokes as required by
Palmer. (No not Harold, but C A). When the load is big enough in
comparison to the radial stiffness, the rim will buckle, this is
epecially prevelant in lightweight bicycle rims and I mean 10oz and
less. These do get trashed (did) because of radial buckling. The
wheels which were susceptible were not tied and soldered, those that
were tied would have their ties examined and possibly re-soldered
before the start of a new season.

On Sat, 21 Nov 2009 20:16:35 +0000, Naqerj wrote:
Ian Smith wrote:
On Fri, 20 Nov, wrote:
On Nov 21, 3:38 am, Ian Smith wrote:
Out of interest, however, has anyone ever seen a purely radial
buckle on a bicycle wheel?
I've dented a rim wall (think severe pinch flat territory). Does
that count?

I don't think so. In fact, it would tend to demonstrate the case that
they don't happen - you can hit the rim hard enough to cause plastic
material failure and no radial buckle occurred.

Like James, I've dented a rim wall but without buckling the rim as a
whole - I have seen a radial buckle, but in a motor cycle wheel. I
reckon it is possible to radial buckle a wheel but you have to hit it
very hard indeed. The other thing with a pedal cycle wheel is that to
get a purely radial buckle you'd not only have to hit it very hard, but
also dead square, otherwise it will buckle laterally as well. Then you
could argue for days about whether that counts as a radial buckle.

It would be relatively simple to determine whether it was a radial
buckle - you'd need to plot distance of rim from hub centre and
see if you had an elastic-type variation from constant, then destress
the wheel and see if it recovers.

Every lateral buckle I've seen on a bicycle wheel looks like a
near-enough purely lateral buckle - the 'pringles' look. I don't
think you can load a bicycle wheel on a bicycle to a level that causes
a radial buckle without first triggering either a plastic failure, or
a lateral buckle.

It's like an euler strut - you can't actually make pin-ended strut
buckle into a two-half-wave mode (even though such a load and failure
exists mathematically) , because it will fail to a one-half-wave mode
first.

regards, Ian SMith
--
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|o o|
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"Ian Smith" wrote in message
. ..

It's like an euler strut - you can't actually make pin-ended strut
buckle into a two-half-wave mode (even though such a load and failure
exists mathematically) , because it will fail to a one-half-wave mode
first.

Is the former S-shape and the latter C-shape? (or maybe (-shape :-) )

On Sun, 22 Nov, Clive George wrote:
"Ian Smith" wrote in message
. ..

It's like an euler strut - you can't actually make pin-ended strut
buckle into a two-half-wave mode (even though such a load and failure
exists mathematically) , because it will fail to a one-half-wave mode
first.

Is the former S-shape and the latter C-shape? (or maybe (-shape :-) )

Yes - if you load a pin-ended strut axially it can (in theory) buckle
to one of any number of modes, but because the first buckling mode can
occur at a lower force than any of the others, it happens first.

So in principle you can load a strut and have it buckle in an S-shape
with two half waves, but in practice, unless you do very specific
things, it will buckle to a C-shape before you get to the load that
the maths says can cause a S-shape. [Specific things would include
restraining the mid-point in such a way that it can't deflect but can
rotate - then you'd be likely to get a S-shape buckle].

Likewise, I think you'll always get a lateral buckle from a wheel
before you get a radial buckle. You might get a material failure
before you get a radial buckle, but I'm not sure about that (which can
also occur in the strut case - if your strut is stiff enough, you
might actually crush it before it buckles).

regards, Ian SMith
--
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|o o|
|/ \|

On 22 Nov, 18:08, Ian Smith wrote:

Likewise, I think you'll always get a lateral buckle from a wheel
before you get a radial buckle.

If always, then wheels have too poor a lateral stability. The loads
are predominantly radial so radial failures should be the dominant
failure mode. The radial buckle is caused by rotation of the rim wrt
the hub, making 1/2 the spokes tighten and half of them slacken. It's
something you may see on a motorcross wheel but unlikely on anything
but the lightest rimmed bicycle wheels prbably powered by Chris Hoy.

*You might get a material failure
before you get a radial buckle, but I'm not sure about that (which can
also occur in the strut case - if your strut is stiff enough, you
might actually crush it before it buckles).

Thin walled rims, less than 1mm have curved braking surfaces which
help to prevent crumpling.