Crank Stiffness Tests???

Quoted message said:

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!

Velonews did some tests in late 2003 and found that the new Dura ace
cranks were by far the stiffest. The carbon cranks were fine though, as
far as stiffness is concerned.

A French magazine tested a bunch of cranks in 2004, and found that the
FSA Energy cranks (fat hollow aluminum) were the stiffest.

The stiffness of carbon cranks varies a lot depending on the design...
but does stiffness even matter? I doubt that there is a perceptible
difference in feel or performance. I'd be more concerned about
durability... and I've seen no published tests for that.

Quoted message said:

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,
even greater than big boy sprinters like mario, and Chalo...

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.

Qui si parla Campagnolo said:

Quoted message said:

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.

Quoted message said:

even greater than big boy sprinters like mario, and Chalo...

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.

well, i weigh 205, and when i'm climbing, there is undoubtedly a
substantial difference between my old solid armed suntour superbe pro
and my dura-ace hollowtech cranks. does it stop me getting up the hill?
no, of course not. but is it nicer to ride? absolutely. you bantam
weights are lucky you never get to experience the difference. noodles
are not much fun.

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

Quoted message said:

Quoted message said:

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,
even greater than big boy sprinters like mario, and Chalo...

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 ?

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
Verneuil-sur-Seine
*******

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

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??????

Peter Chisholm said:

Quoted message said:

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.

Quoted message said:

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, even greater than big boy sprinters like Mario, and Chalo...

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.

I take it this is in the line of frame flex and lost energy. Don't
worry about crank stiffness, worry about crank failure, which can be a
fatal flaw. If a left crank breaks while pedaling in the standing
position adjacent to a ready-mix truck, for instance, the rider WILL
take a dive under the wheels of that truck if he is not lucky enough
to crash into its tires which is also not a benign collision.

Crank manufacturers are not addressing the principal failure modes of
current cranks, which are in bending crosswise to the bicycle and that
occur at the bottom of the stroke and especially the breakout of pedal
eyes. Besides that, Campagnolo is still finishing their Record cranks
with a, more than cosmetic, milky anodizing that causes crack
initiation.

Jobst Brandt

jobst.brandt said:

Don't
worry about crank stiffness, worry about crank failure, which can be a
fatal flaw. If a left crank breaks while pedaling in the standing
position adjacent to a ready-mix truck, for instance, the rider WILL
take a dive under the wheels of that truck if he is not lucky enough to
crash into its tires which is also not a benign collision.

Crank manufacturers are not addressing the principal failure modes of
current cranks, which are in bending crosswise to the bicycle and that
occur at the bottom of the stroke and especially the breakout of pedal
eyes. Besides that, Campagnolo is still finishing their Record cranks
with a, more than cosmetic, milky anodizing that causes crack
initiation.

Well, they probably don't get too many complaints -- most people don't
ride anywhere near the number of miles it takes to break a crank. Those
who do are likely to be sponsored riders who get new equipment all the
time anyway.

Note that these days one can buy a whole new crank w/ chainrings, on sale,
for less than the cost of replacement chainrings from a bike shop. An
engineer from a large bike company once said to me, "it's probably better
that way." (Actually he was even more concerned about BB spindles, and
thus pro-cartridge.) And no, I ain't tellin' who.

So of course you're right, but I can't believe you really think they'd
ever admit it. I know you weren't born yesterday. Maybe it's wishful,
"thinking out loud," but still...

Matt O.

Jobst states:

<Besides that, Campagnolo is still finishing their Record cranks
with a, more than cosmetic, milky anodizing that causes crack
initiation>

When you state "cosmetic, milky anodizing", may I presum you speaking
of Campagnolo's aluminum cranks, not the carbon cranks. Does this same
this same anodizing appear on other Campy cranks like the Centaur and
Veloce aluminum crank like here:

http://www.yellowjersey.org/CENCOMPC.JPG

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

Sandy
Verneuil-sur-Seine FR

Sandy states:

<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. >

One thing about boutique wheels from Mavic, Campy, et al., is the cost
of replacement parts. If you damage the rim or a spoke breaks, how much
does it cost to replace? Its my understanding for fancy boutque wheels
like Mavic's high-end Kyserium (sp?) or Campy pre-built wheels (e.g.,
neutron, etc.), a replacement rim is like $150-200 EACH! Further, both
wheelsets have "proprietary spokes" which also cost $$$. That means if
you're in the middle of nowhere and break a spoke, you can't replace it
with a standard DT or Wheelsmith double-butted spoke! That's sad.....

I've heard a rumor that Tour has tested cranks in May 2005... data
anyone? But this is the most recent I have. Sorry about the columns...
is there some way to keep them straight?

Velonews Nov 2003

Crank lbs/in grams $

Dura-Ace FC-7800 1681 745 366
FSA Carbon Pro SL 1186 710 400
Campy Record Carbon 1176 765 550
Colnago Carbon 1111 795 995
TruVativ Rouleur 1048 825 230
Profile Elite Carbon 995 740 260

Deflection (and force) is at the pedal.
Crank is held in place by a chain around the large ring, so includes
chain, BB, and pedal deflection.

Some French magazine from 2004

Crank N/mm grams Euro

FSA Energy 54.05 624 216
Cannondale Hollowgram 49.75 562 1112
Dura-Ace 48.78 654 479
Strongliight Z'Light 48.43 650 230
Stork Power Arms 48.31 495 650
FRM CU2-R 110 47.62 548 340
Gir's Pro G 46.73 634 445
Stronglight Pulsion 46.73 488 450
Campy Record Carbone 46.40 580 778
Gir's Super G 45.45 596 365
Ritchey WCS 45.35 688 299
Ultegra 45.35 672 172
FRM CU2-R Carbon 45.25 582 650
FSA Carbon Pro Elite 110 45.25 546 515
Miche Grantour 45.15 676 145
Shimano 105 44.94 658 146
FSA Superlight 44.64 538 659
Miche Supertype 43.76 644 290
FSA Team Issue 43.48 598 520
Campy Centaur 43.29 690 148
Look Carbon Power 42.83 620 499
Campy Chorus 42.46 700 218
TA Carmina 42.37 644 264

Methods unknown (to me). For Campy Record Carbone, Velonews's 1176
lbs/in (x 4.45 N/lb / 25.4 mm/in) = 206 N/mm... so Velonews's stiffness
is around 4-5 times higher than what the French mag is saying!
Something is odd here...

For instance, with a fairly normal 100 lb pedal load, the Campy Carbon
would deflect 100/1176 = .085 in according to Velonews, and
445/46.40/25.4 = .378 in according to the French mag.

Quoted message said:

Quoted message said:

...Further, both wheelsets have "proprietary spokes" which also cost $$$. That means
if you're in the middle of nowhere and break a spoke, you can't replace it
with a standard DT or Wheelsmith double-butted spoke! That's sad.....

That is why you have a seattube that you can get into....
I have a 5 year-old pair of Ksyriums purchased them very shortly after
they were released. I have only had them go out of true slightly once.
I trued them up and they have been running very well now for 3000 more
mi. VERY durable wheels. All that said I still carry an extra spoke
for the front, drive and non-drive with me. No problem. Just be
prepared.

Josh McClure
Durst Cycles

Excellent. A couple of questions:
1. what kind of bike do you ride? Do you recommend putting these extra
spokes into say a carbon fiber frame?
2. how are these spokes attached? Or do you just put them into the seat
tube? If so, how do you secure them from rattling?
3. How much do these "extra" spokes cost? Since you appear to be from
a shop, maybe the question is "how much would these extra spokes cost
your customer?"

Ron Ruff said:

I've heard a rumor that Tour has tested cranks in May 2005... data
anyone? But this is the most recent I have. Sorry about the columns...
is there some way to keep them straight?

Velonews Nov 2003

Crank lbs/in grams $

Dura-Ace FC-7800 1681 745 366
FSA Carbon Pro SL 1186 710 400
Campy Record Carbon 1176 765 550
Colnago Carbon 1111 795 995
TruVativ Rouleur 1048 825 230
Profile Elite Carbon 995 740 260

Deflection (and force) is at the pedal.
Crank is held in place by a chain around the large ring, so includes
chain, BB, and pedal deflection.

Some French magazine from 2004

Crank N/mm grams Euro

FSA Energy 54.05 624 216
Cannondale Hollowgram 49.75 562 1112
Dura-Ace 48.78 654 479
Strongliight Z'Light 48.43 650 230
Stork Power Arms 48.31 495 650
FRM CU2-R 110 47.62 548 340
Gir's Pro G 46.73 634 445
Stronglight Pulsion 46.73 488 450
Campy Record Carbone 46.40 580 778
Gir's Super G 45.45 596 365
Ritchey WCS 45.35 688 299
Ultegra 45.35 672 172
FRM CU2-R Carbon 45.25 582 650
FSA Carbon Pro Elite 110 45.25 546 515
Miche Grantour 45.15 676 145
Shimano 105 44.94 658 146
FSA Superlight 44.64 538 659
Miche Supertype 43.76 644 290
FSA Team Issue 43.48 598 520
Campy Centaur 43.29 690 148
Look Carbon Power 42.83 620 499
Campy Chorus 42.46 700 218
TA Carmina 42.37 644 264

Methods unknown (to me). For Campy Record Carbone, Velonews's 1176
lbs/in (x 4.45 N/lb / 25.4 mm/in) = 206 N/mm... so Velonews's stiffness
is around 4-5 times higher than what the French mag is saying!
Something is odd here...

For instance, with a fairly normal 100 lb pedal load, the Campy Carbon
would deflect 100/1176 = .085 in according to Velonews, and
445/46.40/25.4 = .378 in according to the French mag.

Since we don't know the methods, it might be that the two test were
measuring deflection in different directions, or with forces applied in
different directions. Probably the only conclusion you can get out of
this is relative differences within each test, and we could even carp
about that (but thanks!! for the data).

Mark

Mark Janeba said:

Since we don't know the methods, it might be that the two test were
measuring deflection in different directions, or with forces applied in
different directions.

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.

I'm hoping that someone who knows French and has the article could
maybe help out here... or I could email the jpegs I have (don't
remember where I found them). As I said, Tour has done more recent
tests... maybe others have also.

Quoted message said:

Peter Chisholm said:

Quoted message said:

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.

Quoted message said:

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, even greater than big boy sprinters like Mario, and Chalo...

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.

I take it this is in the line of frame flex and lost energy. Don't
worry about crank stiffness, worry about crank failure, which can be a
fatal flaw. If a left crank breaks while pedaling in the standing
position adjacent to a ready-mix truck, for instance, the rider WILL
take a dive under the wheels of that truck if he is not lucky enough
to crash into its tires which is also not a benign collision.

Crank manufacturers are not addressing the principal failure modes of
current cranks, which are in bending crosswise to the bicycle and that
occur at the bottom of the stroke and especially the breakout of pedal
eyes. Besides that, Campagnolo is still finishing their Record cranks
with a, more than cosmetic, milky anodizing that causes crack
initiation.

Jobst Brandt

talking of milky, you still trying to get lactate from the old anodizing
saw jobst? can you post any pics of modern campy cranks failing at the
pedal eye? how about at the spider, their other old favorite spot? no?
well, that's because anodizing is not a problem. now, go to the
library and read a book on the effect of inclusion count on fatigue
life. it would be handy to check out stress corrosion cracking and
anodizing protection while you're there.

Actually, you don't have to log that many miles to break a crank. I
broke some Campys and an Ofmega with fairly low mileage -- and some
Campys with high mileage. Most recently, I was amazed to have broken a
Shimano Ultegra triple with probably less than 10K (although it is hard
to tell because it got switched around to a few different bikes). I was
pretty impressed with the Japanese cranks until then. All you can do
is watch for cracks, and for me, the failures have not been occurring
at the pedal eye, so the Jobst fix (chamfered pedal hole, washers,
etc.) would not have helped.-- Jay Beattie.

jim beam said:

Qui si parla Campagnolo said:

Quoted message said:

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.

Quoted message said:

Quoted message said:

even greater than big boy sprinters like mario, and Chalo...

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.

well, i weigh 205, and when i'm climbing, there is undoubtedly a
substantial difference between my old solid armed suntour superbe pro
and my dura-ace hollowtech cranks. does it stop me getting up the hill?
no, of course not. but is it nicer to ride? absolutely. you bantam
weights are lucky you never get to experience the difference. noodles
are not much fun.

Qui si parla Campagnolo said:

jim beam said:

Qui si parla Campagnolo said:

[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?

Quoted message said:

Quoted message said:

Quoted message said:

even greater than big boy sprinters like mario, and Chalo...

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.

well, i weigh 205, and when i'm climbing, there is undoubtedly a
substantial difference between my old solid armed suntour superbe pro
and my dura-ace hollowtech cranks. does it stop me getting up the hill?
no, of course not. but is it nicer to ride? absolutely. you bantam
weights are lucky you never get to experience the difference. noodles
are not much fun.