Aero wheels for a small light rider

freebsd_frank wrote:

Muppets like you for instance, will punch their text straight into the box and therefore have no editing features available to speak of.

What editing features do you need on an internet forum?

Also, are you deliberately setting out to alienate every cyclist on here, may I suggest that if you ever puncture after using your last tube you don't mention who you are to the helpful soul that offers assistance, as you may find that offer of a tube rescinded.

You are coming across as that guy in the pub who winds everyone up and eventually gets decked, then goes off crying about being the victim.

All typed into the text box, and happily so as it uses less keystrokes.

vonhelmet writes:

I know what vi, vim, latex, Unix, shell scripts, etc are and what they're for. I also know how to use a text box on a webpage so that I don't end up introducing a load of line breaks when I copy in from the wrong tool for the job. It's not like I'm over here typing these posts in MS Word and then copying them in FFS.

If you knew anything about unix and it's tools, you would have known I use
them from my handle. You also would have known that I'm using a GUI
because I'm obviously using a browser to read the webpage. You'd also
know that a standard xterm or other terminal emulator which you open vim in is 80x25 chars. Even gvim and other editors such as emacs defaults to 80x25.
You would also have noticed that my line length is less than 80 chars, and
figured out that I was using a text editor to cut and paste into the html text field in the browser. But no, because you're a drooling moron, you decided to have a go, imply that I was some kind of idiot know-nothing (like you) and accuse me of hitting return whilst directly entering text into the field. If you knew anything about vim (like you say you do), you wouldn't accuse me of using the wrong tool for the job. ie. You're lying.

The short and tall of it is that you're a muppet. Carry on digging!

crikey wrote:

Very stiff and Planet X Pro Carbon are not often seen in the same sentence. Lovely bikes, but not renowned for their stiffness...

But it's alright, you can't feel the difference.

Very stiff and Planet X Pro Carbon are not often seen in the same sentence. Lovely bikes, but not renowned for their stiffness...

That's because people like you believe the drivel people i.e
know-nothings, propagate.

...and Frank, how about a link to the stiffness tests that lead to your conclusion, you naughty engineer?

Stiff to a layman doesn't mean what it does to an engineer.
Engineers work-out a materials stiffness (it's Young's modulus), from the
stress/strain graph of the material tested. A material's then formed into a
certain component and it's resistance to deflection ("stiffness" in layman's
terms) is then also dependent on it's cross-section. In an annulus ie. a tube,
the thicker the wall of the tube and the greater the outside diameter,
the stronger and more resistant to deflection the tube.

Additionally, carbon fibre composites properties are dependent on the
lay-up of the fibres in the material. If stressed longitudinally
(along the length of the fibres), they're strong. If not, lower stress is
required to break the material. In other materials like carbon steel for
instance, you don't get this. It's just as strong whichever way you stress it.

Carbon fibre composite whilst strong, with the caveats above, is brittle.
It will fail before it has deflected to any extent, like glass.

Those are some of the properties of carbon fibre composites. People who say
that carbon fibre composite frame x is less stiff than frame y made out of the
same material are fantasists. The material just doesn't flex to any degree
before failing.

There are various grades of carbon fibre composite. I suspect (although I
don't know) is that the only important property that differs is that some
grades are stronger (ie. have higher UTS and E) than others and they use the
stronger (and probably) more expensive grades for more expensive frames.
You'd be able to use thinner/narrower/lighter tubes for a frame of a similar
strength to one built of an inferior grade.

That's a brief explanation but there's plenty more info on the 'net. This is
quite a good layman's guide which doesn't get too technical and there's also
an explanation of what Young's modulus is linked from that page:

http://www.christinedemerchant.com/carboncharacteristics.html

FYI, I knew SFA about carbon fibre composites until recently. I did the
research before I bought a bike made of the material. Anybody, who has
studied maths and physics at GCSE level should be able to too. It's not rocket
science, you don't have to learn all the arcane details (calculus etc.) to get
a basic grasp of engineering principles but people don't bother doing a bit of
basic research before spouting their baseless opinions. It's not like the old
pre-internet days either. There seems to
be plenty of other engineers on this forum but do they bother to inform other
readers about what they know? Do they apply their knowledge to give an opinion
based on those engineering principles? No. They don't even seem to post any
useful links. WTF, is the internet for if not informing people? Those who
don't agree should go back to Twitter or the Daily Mail site from which they
came and read the rot posted there.

All credit to you for wanting to be informed.

freebsd_frank wrote:

Carbon fibre composite whilst strong, with the caveats above, is brittle.
It will fail before it has deflected to any extent, like glass.

Those are some of the properties of carbon fibre composites.

Carbon fibre composite structures can support relatively high degrees of deflection without failing or inducing permanent deformation.

freebsd_frank wrote:

There are various grades of carbon fibre composite. I suspect (although I
don't know) is that the only important property that differs is that some
grades are stronger (ie. have higher UTS and E) than others and they use the
stronger (and probably) more expensive grades for more expensive frames.

You suspect wrongly.

Fukawitribe writes:

Carbon fibre composite structures can support relatively high degrees of
deflection without failing or inducing permanent deformation.

What structures though? I used the example of a simple tube, assuming the lay
up of the fibres would be in-line with maximal stress.

How about a link to the description of such a structure and it's mechanical
properties? I know it's such a hassle to back up baldly stated facts, I seem
to be the only one on here who does.

From what I read on that site, carbon fibre's mechanical properties are
directional. Whilst you could in theory make a bendy carbon fibre composite by
not using the directional properties of the fibre and instead rely on the
properties of the matrix instead, to quote from the article I gave you a
link to, that wouldn't make sense (why use a strong material and then not make
use of that property?) and in practice:

Because of the way the crystals of carbon fibre orient in long flat ribbon or narrow sheets of honeycomb crystals, the strength is higher running lengthwise than across the fibre. That is why designers of carbon fibre objects specify the direction the fibre should be laid to maximize strength and rigidity in a specific direction. The fibre being aligned with the direction of greatest stress.

And later under the heading: Carbon Fibers are brittle:

When the fibers bend they fails at very low strain. In other words carbon
fibre does not bend much before failing.

You suspect wrongly.

This is getting tiresome: to the next muppet who doesn't supply any links,
from now on I wont bother replying.

freebsd_frank wrote:

This is getting tiresome: to the next muppet who doesn't supply any links,
from now on I wont bother replying.

I think this maybe what most dear readers are secretly hoping for...

freebsd_frank wrote:

Fukawitribe writes:

Carbon fibre composite structures can support relatively high degrees of
deflection without failing or inducing permanent deformation.

What structures though? I used the example of a simple tube, assuming the lay
up of the fibres would be in-line with maximal stress.

How about a link to the description of such a structure and it's mechanical
properties? I know it's such a hassle to back up baldly stated facts, I seem
to be the only one on here who does.

For tubes try here

https://www.youtube.com/watch?v=SDVpRSNtcPQ

and other fun from Fabio Gigli or Google Santa Cruz carbon crush test or similar. Or perhaps, as mentioned by others, look at running prosthetics - hey, look in the sky at planes, at old carbon frame soft tails, at aero blades, carbon spokes, boats, leaf springs, at all sorts of shit.

freebsd_frank wrote:

From what I read on that site, carbon fibre's mechanical properties are
directional. Whilst you could in theory make a bendy carbon fibre composite by
not using the directional properties of the fibre and instead rely on the
properties of the matrix instead, to quote from the article I gave you a
link to, that wouldn't make sense (why use a strong material and then not make
use of that property?) and in practice:

Because of the way the crystals of carbon fibre orient in long flat ribbon or narrow sheets of honeycomb crystals, the strength is higher running lengthwise than across the fibre. That is why designers of carbon fibre objects specify the direction the fibre should be laid to maximize strength and rigidity in a specific direction. The fibre being aligned with the direction of greatest stress.

And later under the heading: Carbon Fibers are brittle:

When the fibers bend they fails at very low strain. In other words carbon
fibre does not bend much before failing.

You suspect wrongly.

This is getting tiresome: to the next muppet who doesn't supply any links,
from now on I wont bother replying.

You know one thing, amongst many, I can't recall you mention this whole time is resin... you might want to consider that next time you're educating the world with your knowledge of composite materials.

No more on this thread now Frank, you want to have more discussion -we'll take it to another. Create it and publish the link - let the OP get on with what they want to talk about.

...and Frank, how about a link to the stiffness tests that lead to your conclusion, you naughty engineer?

FYI, I'm not an engineer. I only studied mech/man engineering a long time ago
and I know that I've forgotten a lot of it. I didn't finish my course, for
various reasons, hence I hold no qualifications and haven't worked as an
engineer. I ended up doing a Dip.Comp. which I got and drifted into IT. I do
however remember enough that I can bone up on it, if I need to.

As for the guys who have posted here who have got qualifications in
engineering. The guy who is chartered, a CEng, IIRC it was Nixster, he will
have gone to university got his BEng/MEng, got a job practising as an engineer
whilst simultaneously working towards his professional examinations with his
Institute. IIRC he's a mech eng so his institute would be IMechE: the
institute of mechanical engineers. Whilst working towards getting chartered,
he would have been guided by somebody who's already a CEng. I believe this
takes a few years. Then if he passes his professional exams he becomes
chartered and becomes a full member of IMechE and has every entitlement to
call himself an "engineer". With becoming a CEng comes considerable
professional prestige but also responsibilities. For instance, if you're
significantly negligent in anyway, you face getting kicked out of your
institute. Not good, you're then professionally doomed. For instance, if
you're a chartered civil engineer and the bridge who's design and construction
you oversaw was to fall down because you fouled up: that's the end of your
career.

CEng's are very much in demand. Because they are chartered they can do stuff
engineers who are not chartered can't and are consequently paid more. It is not
at all unusual for CEng's to become directors of their company, like Nixster.

CEng's and even those who aren't chartered, are held in more respect in
some countries. I believe that in France, for instance, they are held in high
regard and social status. Not so much in this country. I don't know why this
is.

The other guy who posted who had a BEng and MSc and worked in aerospace, isn't
chartered or he didn't mention that he was. He didn't get chartered for
whatever reason; possibly because his career path didn't allow it. If he does
any safety critical work, he would have to be overseen by a CEng and to get
his work "signed-off". So my comment about not flying anymore was done
with tongue firmly in cheek.

This is how I remember it being many years ago. But things might have changed.

In IT for instance, you get guys who like to call themselves "software
engineers" and such like. They are no more an engineer than my dustman. They
might have a degree in Comp.Sci but not necessarily so, they don't have a
professional institute and therefore don't have any professional development.
Because of this, they can range from good to atrocious.

I thought I'd post about engineering as a profession even though it's OT
because it's poorly understood by those who aren't in the profession. I'm sure
Nixster for instance, has had occasions where people have asked him what he
does and when he's told them "mechanical engineer" they've thought he carries
a spanner and works fixing car engines.

crikey wrote:

Frank, you don't half write some rubbish.

It's nice outside, go for a ride eh?

Quite, just what I am going to do, 300km overnight Audax on my new Ti frame. I guess I will be imagining any difference it makes to my comfort levels and speed?