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DaveAldred
Worn
Joined: Mar 19, 2006
Posts: 1,006
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 Posted: Wed 23rd Jul 9:35pm Post subject: |
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My legs fail way before my crank's lack of stiffness becomes apparent. I don't think i've ever spent a second thinking about the stiffness of my old Deore square taper crank's. They just work.
I would say pursuing even stiffer cranks is ssiping in the wind compared to cutting rolling resistance, getting a bit more aero, or stopping your foul whining.
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Al_Bushman
Flogged
Joined: Jun 24, 2006
Posts: 2,074
Location: In the box
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| Posted: Thu 24th Jul 10:04pm Post subject: |
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So super-bling cranks (record/ DA, SRAM Red etc) are all knaw factor with a few extra grams saved! 
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JimmyM
Dusty
Joined: May 03, 2008
Posts: 77
Location: Christchurch
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| Posted: Thu 24th Jul 10:44pm Post subject: |
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| Al_Bushman wrote: | | So super-bling cranks (record/ DA, SRAM Red etc) are all knaw factor with a few extra grams saved! |
If not the whole corresponding groupset 
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danose
Mangled
Joined: May 27, 2004
Posts: 10,753
Location: Nose City
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| Posted: Fri 25th Jul 11:23am Post subject: |
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| Al_Bushman wrote: | | So super-bling cranks (record/ DA, SRAM Red etc) are all knaw factor with a few extra grams saved! |
for the top pros - no, I'm quite willing to believe top sprinters CAN tell the diff in stiffness
for average club level racers - you're right, it's more about having the nice toys than any actual percievable benefit.
in your case - if you were looking for stuff to upgrade on your speshy the cranks would probably be bottom of the list. You'd get much more noticable benefit from wheels (since the BM races are basically flat I'd go something aero/deep section)
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Oli
Mangled
Joined: Aug 03, 2005
Posts: 32,341
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| Posted: Fri 25th Jul 11:28am Post subject: |
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Even the top pros would be very hard pressed to pick crank stiffness differences, I reckon. Unless maybe they were doing a bunch of back to back tests.
Otherwise there are too many variables to consider - tyre pressure/tpi, frame stiffness, shoes, road surfaces, pedal axle strength - to determine crank differences.
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sifter
Moving forward
Joined: Nov 13, 2003
Posts: 10,845
Location: Wellington
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| Posted: Fri 25th Jul 11:29am Post subject: |
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| Oli wrote: | | Otherwise there are too many variables to consider - tyre pressure/tpi, frame stiffness, shoes, road surfaces, pedal axle strength - to determine crank differences. |
I reckon you could add crankiness to that too 
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Joel
Wrecked
Joined: Mar 26, 2002
Posts: 5,871
Location: Welly
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| Posted: Fri 25th Jul 11:33am Post subject: |
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you would have to be pretty senstive to your gear to pick whether it was the frame or the cranks flexing... i would have thought.
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SlackBoy
Mangled
Joined: Dec 25, 2001
Posts: 18,048
Location: Showing my tan lines
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| Posted: Fri 25th Jul 11:33am Post subject: |
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Now that's not fair. Oli's not been getting much sleep, it is Le Tour time you know
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danose
Mangled
Joined: May 27, 2004
Posts: 10,753
Location: Nose City
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| Posted: Fri 25th Jul 11:39am Post subject: |
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| Joel wrote: | | you would have to be pretty senstive to your gear to pick whether it was the frame or the cranks flexing... i would have thought. |
my point being the top pro teams have the gear (and the motivation) to measure all that stuff - to them it can/does matter (when a few secs is the diff between GC and 4th place)
without all the scientific doodads there's NO WAY you'd tell by feel
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Oli
Mangled
Joined: Aug 03, 2005
Posts: 32,341
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| Posted: Fri 25th Jul 11:47am Post subject: |
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If the top pro teams were measuring it, wouldn't they all be on the stiffest?
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radical_edward
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Joined: Mar 10, 2004
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Location: The not too distant future...
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| Posted: Fri 25th Jul 11:47am Post subject: |
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| Nick_K wrote: | | Don't track riders still use sq taper? |
The actual track bikes that I have seen lately have all had carbon cranks with outboard bearings or ISIS. Where manufacturers have a choice, they are shifting their track cranks to whatever system their road cranks use.
There are still a lot of low end cranks that are square taper, mostly older euro brands that are favoured by the hipster market. And the Japanese cranks, which are fiercely regulated due to there being money on the races.
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radical_edward
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| Posted: Fri 25th Jul 11:58am Post subject: |
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| Oli wrote: | Even the top pros would be very hard pressed to pick crank stiffness differences, I reckon. Unless maybe they were doing a bunch of back to back tests.
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But you felt your own bike become more responsive when you changed the cranks. True that top pros no nothing about cycling when compared to their mechanic*...
It is not hard to put an old crank on a test jig, and then a new crank, and then declare that the flex is now in the frame/wheels.
I have had a horrible time with low end ebb singlespeed cranks over the last year. I am coming to the conclusion that distributed flex over the entire system is a better option than a totally rigid system with all the stress from flex on a single interface. As far as longevity goes, that is. Can't speak about winning any races except as conjecture
*Not even a hint of sarcasm. Mechanics can be in the game for the length of many many pro cyclists careers.
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Oli
Mangled
Joined: Aug 03, 2005
Posts: 32,341
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| Posted: Fri 25th Jul 12:02pm Post subject: |
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My comment was on going from one cheap set of old square taper cranks to a set of lovely Campag UT cranks on a bike that I ride most days with the same tyres, shoes, etc., etc...
That's a BIG change, and even an idiot like me could pick the diff. 
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danose
Mangled
Joined: May 27, 2004
Posts: 10,753
Location: Nose City
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| Posted: Fri 25th Jul 12:19pm Post subject: |
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| Oli wrote: | | If the top pro teams were measuring it, wouldn't they all be on the stiffest? |
depends on their sponsorship agreements
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Tristan
Scuffed
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Joined: Apr 15, 2003
Posts: 437
Location: Building wheels
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| Posted: Fri 25th Jul 1:41pm Post subject: |
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| Oli wrote: | | If the top pro teams were measuring it, wouldn't they all be on the stiffest? |
Last year Cancellara used bottom-of-the-line Gossamer cranks from sponsor FSA
http://www.cyclingnews.com/road/2007/tour07/tech/probike.php?id=/tech/2007/probikes/tour_cancellara_csc_cervelo
| cyclingnews.com wrote: | | According to Team CSC mechanic Alejandro Torralbo, Cancellara began using the Gossamer cranks during the Spring classics, but grew more comfortable on them than carbon ones because he feels that they're stiffer. We have our doubts as to whether or not a bench test would support that statement, but with the raise of a brow and wry grin, Torralbo explained in simpler terms: "He's a strong man." |
The FSA cranks of this generation were quite flexy in stiffness tests so this may have some merit.
Most new cranks seem to be moving towards large spindles etc to save weight rather than increase stiffness.
Shimano, SRAM and Campy all claim that rear cassette cogs shift much better when spidered because of the reduction in flex....if this is true for cassette cogs then it must be true for chainrings as well. Maybe chainring stiffness is more important than crank stiffness?
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