Crank Stiffness Tests???

Sandy said:

On another front - I just got a pair of Aksiums (Mavic's new cheapo wheels)
for winter use, and they have around 1000 km on them already. Excellent
wheels, IMHO. What would you have cooked up for me for the price of 160
euros ?? Yes, bought at the local store, not by mail or e-mail.

160 euros should be at least nearly enough for open pro or aerohead,
ultegra/XT, and single-butted DT or Wheelsmith spokes. Not anything
particularly shabby.

Jasper

Ron Ruff said:

Doesn't really make sense though... since the only sensible way to test
would be similar to how Velonews did it. If the French mag mounted all
the cranks on an actual frame so that they were really getting frame
deflections also, then the numbers would make some sense... but that is
a poor way to test cranks.

Applying force downward at the pedal or sideways on the crank eye makes a
*huge* difference.

Jasper

Jasper Janssen said:

Quoted message said:

Doesn't really make sense though... since the only sensible way to
test would be similar to how Velonews did it. If the French
magazine mounted all the cranks on an actual frame so that they
were really getting frame deflections also, then the numbers would
make some sense... but that is a poor way to test cranks.

Let's leave the bicycle out of this for now. Because that would only
cloud the results, what frame should be chosen?

Quoted message said:

Applying force downward at the pedal or sideways on the crank eye
makes a *huge* difference.

I believe there are two static tests that would give a figure of merit
for cranks. The only crank to test is the left one since it is the
longer and more slender one at its base, otherwise being identical to
the right crank.

The should crank mounted on its designed spindle held in a rigid
collet up to its normal point of bearing support. At a standard
distance from the face of the crank, apply a downward load to a dummy
pedal shaft with the crank first in the horizontal (forward) position
and then straight down.

This would give its torsional rigidity in its forward position and its
bending strength when downward. Because most failures result from the
downward position, this is important for strength while the forward
one would reveal whether the cross section is torsionally rigid.
I-beams are notoriously flimsy in torsion and crank designers
gravitate toward this shape.

Additionally, the crank should be subjected to its maximum design load
in both positions once and then inspected under a microscope for
surface cracking, especially aluminum cranks that have been anodized.

Carbon fiber cranks are still less well defined in their failure modes
that separation between the metal and fiber parts may be their feet of
clay.

Jobst Brandt

Quoted message said:

Jasper Janssen writes:

Quoted message said:

Quoted message said:

Applying force downward at the pedal or sideways on the crank eye
makes a *huge* difference.

I believe there are two static tests that would give a figure of merit
for cranks. The only crank to test is the left one since it is the
longer and more slender one at its base, otherwise being identical to
the right crank.

The should crank mounted on its designed spindle held in a rigid
collet up to its normal point of bearing support. At a standard
distance from the face of the crank, apply a downward load to a dummy
pedal shaft with the crank first in the horizontal (forward) position
and then straight down.

The straight down version would be more-or-less the equivalent of directly
applying a load sideways on the crank face (ie, hold the crank horizontal
by the spindle and apply a load to the pedal eyelet, since most testing
machines are vertically oriented). More less than more, because the
pedal/crank eye interface contributes significantly, and can be different
between cranks. Especially so for carbon, where there is an extra material
interface designed in the crank, and thus no "but all cranks act the same
in that respect" thing.

Quoted message said:

This would give its torsional rigidity in its forward position and its
bending strength when downward. Because most failures result from the
downward position, this is important for strength while the forward
one would reveal whether the cross section is torsionally rigid.
I-beams are notoriously flimsy in torsion and crank designers
gravitate toward this shape.

Apart, of course, from the ones that are gravitating to hollow girders.

I think there is a third parameter, that might be a bit harder to test
for: Chainring versus pedal versus spindle movement. You really need to
include the rings and not just the spider because rings of equal number of
teeth with a smaller spider will be, in and of themselves, flexier (but
the spider will be less flexible and the question is whether it matters as
a whole).

Quoted message said:

Carbon fiber cranks are still less well defined in their failure modes
that separation between the metal and fiber parts may be their feet of
clay.

Depends, I think. What you really need in bonding things like mast stay
eyelets (think tonnes load) to (glass)fiber composite boat hulls is mainly
a big metal plate to distribute the load. So I'd expect that ideally, you
want something as a base that is more or less a (weak) crank, and then
slather it with copious amounts of fibers for strength. So more or less a
composite/alu/composite sandwich construction.

Quoted message said:

The only crank to test is the left one since it is the
longer and more slender one at its base, otherwise being identical to
the right crank.

After looking at the French test again, I see that their deflections
must have included the spindle torque (left crank?). They show one
chart where a few of the cranks were tested with different bottom
brackets, and the Record crank with a TA Ti BB, was only 80% of the
stiffness of the Record crank with Record BB. It appears that the BB
has a much greater effect on the stiffness (as they measured it) than
the crank. I don't what particular BBs were used with which cranks for
their final results.

Quoted message said:

Because most failures result from the
downward position, this is important for strength

I thought we were supposed to be applying much higher forces near the
horizontal crank position... with good technique, at least...

Ron Ruff said:

Quoted message said:

The only crank to test is the left one since it is the longer and
more slender one at its base, otherwise being identical to the
right crank.

Quoted message said:

After looking at the French test again, I see that their deflections
must have included the spindle torque (left crank?). They show one
chart where a few of the cranks were tested with different bottom
brackets, and the Record crank with a TA Ti BB, was only 80% of the
stiffness of the Record crank with Record BB. It appears that the BB
has a much greater effect on the stiffness (as they measured it)
than the crank. I don't what particular BBs were used with which
cranks for their final results.

Quoted message said:

Quoted message said:

Because most failures result from the downward position, this is
important for strength

Quoted message said:

I thought we were supposed to be applying much higher forces near
the horizontal crank position... with good technique, at least...

Forget about technique. Everyone stands on a downward pedal now and
then and more often if climbing while standing. Anyway, if you review
crank failures, the nearly all beak across the brand dimension of the
crank that is loaded when standing on the downward pedal.

Higher force may be on the downstroke, but the cross section is far
smaller in bending at the bottom of the stroke. That stress goes as
the third power of the cross section height in that plane. Cranks are
often twice as broad as they are thick, especially the I-beam shaped
models that also have high stress concentration on the outer ridges.

Jobst Brandt

jim beam said:

Qui si parla Campagnolo said:

jim beam said:

Qui si parla Campagnolo wrote:

>[email hidden] wrote:
>
>
>>hi, anyone know of any good crank stiffness tests out there that have
>>been done to compare newer road cranks? with all these light weight
>>carbon models coming out i'd be interested to see how stiff they are.
>>thanks!
>
>
>Try to remember that crank and BB stiffness tests were accomplished by
>a gorilla machine that exerted FAR more force than the mere human can,

peter, with respect, those machines exert forces in the same range as
humans. the only reason machines are used is so that the tests are
controlled & repeatable. and this is not an accelerated fatigue test,
just deflection. deflection with just one pound of force is measurable,
so the relative difference between cranks can be gauged - and that's the
objective.

Give Lennard a shout and ask him about their most recent crank/BB
tests.

why?

Cuz he conducted the latest crank/BB stiffness tests...is why.

Quoted message said:

Quoted message said:

Sandy said:

Gee, Peter, I am trying to remember. I had to look it up. The figures I
quoted from Le Cycle magazine's test were far from extraordinary. I wonder
where your tests were published, so I could get a look at them. You didn't
make that statement up, by any chance ???

Quoted message said:

If they used forces like those exerted by the average, 45 yr old
cyclist, then the results would have been inconclusive and not able to
be used by the marketeers.

So I guess you're saying that *any* crank is good enough. Even cranks from
The Republic ?

Huh? I guess I'll say it s l o w l y for you. By saying one crank or
another is 'lighter/stiffer/more reliable', implys that others are
heavy/flexy/unreliable and that isn't true. Crank tests are like any
'test', are the stuff of magazines, bike stuff sellers. Very much like
wind tunnel tests of this or that, then applied etched in stone, to a
cyclist..crappola.

Quoted message said:

On another front - I just got a pair of Aksiums (Mavic's new cheapo wheels)
for winter use, and they have around 1000 km on them already. Excellent
wheels, IMHO. What would you have cooked up for me for the price of 160
euros ?? Yes, bought at the local store, not by mail or e-mail.
--
Sandy

yep, these are $250 retail in the US...how about a Veloce or 105
hubset, double butted spokes(those are straight gauge, asian bladed), a
Velocity Aero or new Mavic 'sport' rim....better rear hub, certainly,
same price, less weight..but not French, tho, i guess that's what sways
you.

Sandy said:

Dans le message de
news:[email hidden],
[email hidden] <[email hidden]> a réfléchi, et puis a déclaré :

Quoted message said:

I'd find it hard to believe that there is no measureable difference,
many of them are totally different in construction. Kind of like most
bike frames are similar in shape, but they all sure aren't similar in
stiffness! Anyone know of a web link or anything at all that has
published numbers from a legitimate test? I think if we had one to
look at, we could figure out how much of a performance difference
that's going to have. Even a tiny amount of difference might add up
to quite a bunch of seconds in something like a climb or time
trial..........wonder if Shimano has numbers anywhere on their 9spd
vs. 10spd cranks??????

Mentioned before - it's in PAPER in the magazine Le Cycle.
What they found (not from Shimano, but from testing) was that the Ultegra
10V crankset was MORE rigid than the DuraAce.

You allergic to print ?

I guess I'm not the only person you are eager to be a [censored] to.....why
not sit down, eat a baggette, drink some of your overpriced vino and
relax a wee bit.

Quoted message said:

I wish I could still worry about chasing seconds, instead of minutes, in
TT's.
--
Bonne route !

Sandy
Verneuil-sur-Seine FR

Dans le message de
news:[email hidden],
Qui si parla Campagnolo <[email hidden]> a réfléchi, et puis a déclaré :

Quoted message said:

Sandy said:

Gee, Peter, I am trying to remember. I had to look it up. The
figures I quoted from Le Cycle magazine's test were far from
extraordinary. I wonder where your tests were published, so I could
get a look at them. You didn't make that statement up, by any
chance ???

Quoted message said:

If they used forces like those exerted by the average, 45 yr old
cyclist, then the results would have been inconclusive and not able
to be used by the marketeers.

So I guess you're saying that *any* crank is good enough. Even
cranks from The Republic ?

Huh? I guess I'll say it s l o w l y for you. By saying one crank or
another is 'lighter/stiffer/more reliable', implys that others are
heavy/flexy/unreliable and that isn't true. Crank tests are like any
'test', are the stuff of magazines, bike stuff sellers. Very much like
wind tunnel tests of this or that, then applied etched in stone, to a
cyclist..crappola.

Saying it even more slowly for you - you made that stuff up. A general
statement with nothing behind it, except your reputation for being a crank
[sic -myself].

Light versus heavy is too easily measured. Rigidity, too. Reliability of
all of the current models is so high, I'm surprised anyone (except Mr
Brandt) makes noise about it.

And lest we forget - YOU sell things, too. Just like, but more directly,
the magazines you can't and won't read.

Quoted message said:

Quoted message said:

On another front - I just got a pair of Aksiums (Mavic's new cheapo
wheels) for winter use, and they have around 1000 km on them
already. Excellent wheels, IMHO. What would you have cooked up for
me for the price of 160 euros ?? Yes, bought at the local store,
not by mail or e-mail. --
Sandy

yep, these are $250 retail in the US...how about a Veloce or 105
hubset, double butted spokes(those are straight gauge, asian bladed),
a Velocity Aero or new Mavic 'sport' rim....better rear hub,
certainly, same price, less weight..but not French, tho, i guess
that's what sways you.

Mavic could be Indonesian or Coloradan, and it would mean no more than its
being French. The fact is that very few units of the enormous quantity
produced fails. Take out user error (crashing, etc.), miniscule amounts.
Unless you have real figures to prove me wrong, this remains true. And the
people who put the wheels together do it all the time, all day long, all
work week, not just in between promoting their Ergolever repair facility, or
dumping on innovation. They do that, QA is a further safeguard, and the
wheels sell because they work. Marketing - advertising - won't sell a
product for as long as Mavic has been around. You get a voice here because
it's an open forum, not because you're right. Repetition in advertising may
make some people believe things. Just like some may believe Mavic to be
inferior because you like to rant on your competitors.

And we still don't know your price. Figure the euros I quoted is equal in
dollars, as the VAT is included. So, for 160 USD, what do you sell ?
--
Sandy
Verneuil-sur-Seine
*******

La vie, c'est comme une bicyclette,
il faut avancer pour ne pas perdre l'équilibre.
-- Einstein, A.

Dans le message de
news:[email hidden],
Qui si parla Campagnolo <[email hidden]> a réfléchi, et puis a déclaré :

Quoted message said:

Sandy said:

Gee, Peter, I am trying to remember. I had to look it up. The
figures I quoted from Le Cycle magazine's test were far from
extraordinary. I wonder where your tests were published, so I could
get a look at them. You didn't make that statement up, by any
chance ???

Quoted message said:

If they used forces like those exerted by the average, 45 yr old
cyclist, then the results would have been inconclusive and not able
to be used by the marketeers.

So I guess you're saying that *any* crank is good enough. Even
cranks from The Republic ?

Huh? I guess I'll say it s l o w l y for you. By saying one crank or
another is 'lighter/stiffer/more reliable', implys that others are
heavy/flexy/unreliable and that isn't true. Crank tests are like any
'test', are the stuff of magazines, bike stuff sellers. Very much like
wind tunnel tests of this or that, then applied etched in stone, to a
cyclist..crappola.

Saying it even more slowly for you - you made that stuff up. A general
statement with nothing behind it, except your reputation for being a crank
[sic -myself].

Light versus heavy is too easily measured. Rigidity, too. Reliability of
all of the current models is so high, I'm surprised anyone (except Mr
Brandt) makes noise about it.

And lest we forget - YOU sell things, too. Just like, but more directly,
the magazines you can't and won't read.

Quoted message said:

Quoted message said:

On another front - I just got a pair of Aksiums (Mavic's new cheapo
wheels) for winter use, and they have around 1000 km on them
already. Excellent wheels, IMHO. What would you have cooked up for
me for the price of 160 euros ?? Yes, bought at the local store,
not by mail or e-mail. --
Sandy

yep, these are $250 retail in the US...how about a Veloce or 105
hubset, double butted spokes(those are straight gauge, asian bladed),
a Velocity Aero or new Mavic 'sport' rim....better rear hub,
certainly, same price, less weight..but not French, tho, i guess
that's what sways you.

Mavic could be Indonesian or Coloradan, and it would mean no more than its
being French. The fact is that very few units of the enormous quantity
produced fails. Take out user error (crashing, etc.), miniscule amounts.
Unless you have real figures to prove me wrong, this remains true. And the
people who put the wheels together do it all the time, all day long, all
work week, not just in between promoting their Ergolever repair facility, or
dumping on innovation. They do that, QA is a further safeguard, and the
wheels sell because they work. Marketing - advertising - won't sell a
product for as long as Mavic has been around. You get a voice here because
it's an open forum, not because you're right. Repetition in advertising may
make some people believe things. Just like some may believe Mavic to be
inferior because you like to rant on your competitors.

And we still don't know your price. Figure the euros I quoted is equal in
dollars, as the VAT is included. So, for 160 USD, what do you sell ?
--
Sandy
Verneuil-sur-Seine
*******

La vie, c'est comme une bicyclette,
il faut avancer pour ne pas perdre l'équilibre.
-- Einstein, A.

Sandy said:

Marketing - advertising - won't sell a
product for as long as Mavic has been around.

Of course not. It requires a steady supply of hapless or obtuse
customers as well.

It seems that not only the USA but France as well has its quota.

In article <[email hidden]>,

Quoted message said:

drink some of your overpriced vino and
relax a wee bit.

I don't know if it's a good time to dispel this rumor, but in France it's
possible to find a lot of pretty darn good wines that are far lower in
price than what you'll find in the USA.

Just thought I'd help,
john

In article <[email hidden]>,

Sandy said:

Marketing - advertising - won't sell a
product for as long as Mavic has been around.

Which Mavic? The name has changed hands at least once.
Marketing is something Mavic does very well these days.
Every one is waiting for their 2007 component set. Mavic
rims used to be the very best rims in the world, better
than the rims with the Mavic name on them today.

--
Michael Press

[email hidden] (John Red-Horse) wrote in
news:[email hidden]:

Quoted message said:

In article
<[email hidden]>,

Quoted message said:

drink some of your overpriced vino and
relax a wee bit.

I don't know if it's a good time to dispel this rumor, but in
France it's possible to find a lot of pretty darn good wines that
are far lower in price than what you'll find in the USA.

I will second that having just returned (from France) and done my
damnest to counteract falling wine consumption.

Sandy said:

Dans le message de
news:[email hidden],
Qui si parla Campagnolo <[email hidden]> a réfléchi, et puis a déclaré :

Quoted message said:

Sandy said:

Gee, Peter, I am trying to remember. I had to look it up. The
figures I quoted from Le Cycle magazine's test were far from
extraordinary. I wonder where your tests were published, so I could
get a look at them. You didn't make that statement up, by any
chance ???

> If they used forces like those exerted by the average, 45 yr old
> cyclist, then the results would have been inconclusive and not able
> to be used by the marketeers.

So I guess you're saying that *any* crank is good enough. Even
cranks from The Republic ?

Huh? I guess I'll say it s l o w l y for you. By saying one crank or
another is 'lighter/stiffer/more reliable', implys that others are
heavy/flexy/unreliable and that isn't true. Crank tests are like any
'test', are the stuff of magazines, bike stuff sellers. Very much like
wind tunnel tests of this or that, then applied etched in stone, to a
cyclist..crappola.

Saying it even more slowly for you - you made that stuff up. A general
statement with nothing behind it, except your reputation for being a crank
[sic -myself].

Light versus heavy is too easily measured. Rigidity, too. Reliability of
all of the current models is so high, I'm surprised anyone (except Mr
Brandt) makes noise about it.

And lest we forget - YOU sell things, too. Just like, but more directly,
the magazines you can't and won't read.

Quoted message said:

Quoted message said:

On another front - I just got a pair of Aksiums (Mavic's new cheapo
wheels) for winter use, and they have around 1000 km on them
already. Excellent wheels, IMHO. What would you have cooked up for
me for the price of 160 euros ?? Yes, bought at the local store,
not by mail or e-mail. --
Sandy

yep, these are $250 retail in the US...how about a Veloce or 105
hubset, double butted spokes(those are straight gauge, asian bladed),
a Velocity Aero or new Mavic 'sport' rim....better rear hub,
certainly, same price, less weight..but not French, tho, i guess
that's what sways you.

Mavic could be Indonesian or Coloradan, and it would mean no more than its
being French. The fact is that very few units of the enormous quantity
produced fails. Take out user error (crashing, etc.), miniscule amounts.
Unless you have real figures to prove me wrong, this remains true. And the
people who put the wheels together do it all the time, all day long, all
work week, not just in between promoting their Ergolever repair facility,or
dumping on innovation. They do that, QA is a further safeguard, and the
wheels sell because they work. Marketing - advertising - won't sell a
product for as long as Mavic has been around. You get a voice here because
it's an open forum, not because you're right. Repetition in advertising may
make some people believe things. Just like some may believe Mavic to be
inferior because you like to rant on your competitors.

And we still don't know your price. Figure the euros I quoted is equal in
dollars, as the VAT is included. So, for 160 USD, what do you sell ?
--
Sandy
Verneuil-sur-Seine

My rant to you was because you slammed the guy that asked for a source
of the information. It had nothing to do with wheels, everything to do
with him being 'allergic to print'.

Ya gotta get out more. Euros are not equal to dollars, not even close.
I just went to Milan and got 65 Euros for $100...$262 = $160 euros and
for that a Veloce hubset, DT dbl butted spokes, Velocity or Mavic
'Sport' rims...like I said before. Better rear hub, by far, probobly
lighter, probably more relaible and easier to fix, like I said before.

Qui si parla Campagnolo said:

Ya gotta get out more. Euros are not equal to dollars, not even close.
I just went to Milan and got 65 Euros for $100...$262 = $160 euros and
for that a Veloce hubset, DT dbl butted spokes, Velocity or Mavic
'Sport' rims...like I said before. Better rear hub, by far, probobly
lighter, probably more relaible and easier to fix, like I said before.

Doesn't work that way. Prices for bike and computer stuff are pretty much
the same number in euros as in dollars. The exchange rate is about 30% in
favour of the euro, but sales tax/VAT in europe takes care of about 20% of
that, and the other 10% is just things being generally more expensive
here.

Jasper

Dans le message de
news:[email hidden],
Qui si parla Campagnolo <[email hidden]> a réfléchi, et puis a déclaré :

Quoted message said:

Ya gotta get out more. Euros are not equal to dollars, not even close.
I just went to Milan and got 65 Euros for $100...

Not quite - current exchange (today) is 1,19 USD for 1 euro.
Our VAT is in the price I quoted, at 19,5%, making it a wash, numerically.
No shipping.

Quoted message said:

$262 = $160 euros and
for that a Veloce hubset, DT dbl butted spokes, Velocity or Mavic
'Sport' rims...like I said before.

So for ONE HUNDRED dollars more, you come up with something OK. And when
you sell it by internet, it turns into "wheels in a box".

Quoted message said:

Better rear hub, by far, probobly
lighter, probably more relaible and easier to fix, like I said before.

As you have said many, many times before.

I'll take the nearly half-price deal. Not your "wheels in a box". Thanks.
--
Sandy
Verneuil-sur-Seine
*******

La vie, c'est comme une bicyclette,
il faut avancer pour ne pas perdre l'équilibre.
-- Einstein, A.

Quoted message said:

Jasper Janssen said:

Simply to go for worst-case, I'd probably do it at the end of the
pedal.

There is a relationship between rotational torque and lateral bending,
both of which affect rigidity. Just the same, rigidity is not a
reasonable consideration with cranks that don't break, so I think the
whole subject is something for the weight wienies.

Depends on if nothing starts touching that shouldn't be touching from the
flexing.

Quoted message said:

Quoted message said:

However, why does the spider/chainring stiffness not matter? It's
not a safety issue (much), admittedly, but purely on stiffness and
energy-loss-into-flexing grounds it ought to matter, surely? There
are people around who've managed to collapse spider/chainrings,
while the cranks themselves took the load.

There is no significant flex in the spider and especially the
chainring. I rode on much flimsier CW spiders and rings in the days
of steel cranks and noticed no flex. Pedal flex is primarily in the
bicycle frame, not in cranks, crank spiders or chainrings. I think
the whole subject is off base because crank failure is the main
parameter of interest, the micro-motion of crank flex being trivial in
comparison. Just sit on your bicycle and push on one pedal. There is
significant motion but it isn't in the crank assembly.

Then how do people taco their chainrings? The flex as a result of pedal
loading may be in the cranks, bb, and frame, but the load coming from the
chain has to have an effect on CW/spiders.

Quoted message said:

Cranks have been made for a long time now and there is no excuse for
using the I-beam shape that is still popping up aplenty. Servo
brakes, and non linear brakes are no good in bicycles for the same
reasons they are no good on motor vehicles.

Power-assisted brakes seem to be used in many vehicles.

Jasper

Jasper Janssen said:

Quoted message said:

Quoted message said:

Simply to go for worst-case, I'd probably do it at the end of the
pedal.

Quoted message said:

Quoted message said:

There is a relationship between rotational torque and lateral
bending, both of which affect rigidity. Just the same, rigidity is
not a reasonable consideration with cranks that don't break, so I
think the whole subject is something for the weight wienies.

Quoted message said:

Depends on if nothing starts touching that shouldn't be touching
from the flexing.

Quoted message said:

Quoted message said:

Quoted message said:

However, why does the spider/chainring stiffness not matter? It's
not a safety issue (much), admittedly, but purely on stiffness and
energy-loss-into-flexing grounds it ought to matter, surely?
There are people around who've managed to collapse
spider/chainrings, while the cranks themselves took the load.

Quoted message said:

Quoted message said:

There is no significant flex in the spider and especially the
chainring. I rode on much flimsier CW spiders and rings in the
days of steel cranks and noticed no flex. Pedal flex is primarily
in the bicycle frame, not in cranks, crank spiders or chainrings.
I think the whole subject is off base because crank failure is the
main parameter of interest, the micro-motion of crank flex being
trivial in comparison. Just sit on your bicycle and push on one
pedal. There is significant motion but it isn't in the crank
assembly.

Quoted message said:

Then how do people taco their chainrings? The flex as a result of
pedal loading may be in the cranks, bb, and frame, but the load
coming from the chain has to have an effect on CW/spiders.

I don't believe that is caused by CW or spider flex but rather extreme
chainline and frame flex that allows the chain to pull substantially
to one side. I climbed Filbert street in SF 31.5% in a gear large
enough to require a chain tension of at least 600lbs with no damage to
flimsy CW's. The chain line as off axis by 1.5 sprocket widths going
from the inner of two CW's to the leftmost of a five speed cluster.
That's not what CW benders are doing. They are in big crossover mode.

Quoted message said:

Quoted message said:

Cranks have been made for a long time now and there is no excuse for
using the I-beam shape that is still popping up aplenty. Servo
brakes, and non linear brakes are no good in bicycles for the same
reasons they are no good on motor vehicles.

Quoted message said:

Power-assisted brakes seem to be used in many vehicles.

Just the same power brake response is linear and on bicycles there is
no power other than the rider so that is not an option. Power assist
is only a multiplier, not a variable mechanical advantage.

Jobst Brandt