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say, v-news has a interesting bit - testing a bunch of high end cranks for stiffness with weight and cost factored in. the new DA did remarkably well, basically coming in at least 150% better than everything else in stiffness , weight/stiffness, and weight/stiffness/cost. in some of these the factor was better than 200% over most. second best under these parameters was the carbon fsa, tho still trailing the DA by the above margins.
mind you, i have never felt any crank flex at ALL, myself - but there you go.
when shimano decides to flex a bicep tho, a smart man will look to duck, and fast. just ask any early 90's boutique cnc parts maker!
Thanks for the info. Most serious bike guys claim the stiffness comes from the bottom bracket spindle diameter rather than the cranks. That would explain why the DA cranks with their massive spindle perform the best.
Still, I think I'll wait a couple of years until the technology trickles down to Ultegra (ala XTR to 2004 XT). It will cost a bit less and hopefully not be quite so ugly.
ya, you are right of course, john. it was a bb/crank test. and, in the same v-news they report being ushered into a back room to be shown a FSA outboard bb copy of the DA, so expect that soon. given this, it could be said that if weight and stiffness matter to you it would be not such a grand idea to go off buying a current ( to me stupid anyway..........) taiwanese carbon-wrapped-over-foam-and-aluminum crank. better to wait, if that sort of thing is what you like.
similarly, twith this success perhaps the long awaited large diameter bb shell ( ala' c-dale) will wither on the vine entirely.
most of my bikes are still square taper phil's tho, so whatever.
Your math needs a little work but the DA did come out ahead in that protocol. As a weight weenie I was most interested in the FSA Superlight results (they don't use the aluminum spine in it btw), combined with a lightweight ISIS BB they came out about 85g less than the DA combo.
It was definitely a BB/crank test. The inability to use identical BB's results in no real info regarding crank stiffness. Since all the traditional carbon cranks beat the traditional aluminum one in the test it seems like a carbon crank with the shimano system would beat all of them.
i will stand corrected on the FSA superlight, or ultralight, or whateverthehell, mises. but, with regard to the old school forged aluminum crank ( the truvativ ), while not quite as good as the carbon FSA in wt/stiffness, it blew it away in wt/stiffness/cost. thus, i conclude the FSA carbon is a poor choice from either the wt/stiffness category where DA beats it handily - or from the wt/stiffness/cost perspective where a plain 'ole forged aluminum crank whups its be-hind. what is the attraction, other than looks, i wonder.
from my understanding the neg mass crank does what you propse, but i gether it will cost as much as the space shuttle.
the upcoming FSA outboard bb/crank will indeed be interesting. my main point is that buying an FSA now - like all those 50x34 fans are doing - seems a waste, as we can bet the new one will be noticeable better than the present as it employs the outboard bb.
For a cogent (ha!) and lively discussion of this very subject, pop on over to the velonews tech forum and learn what the facts of the matter are on this "stiffness" thing. Prepare to be amazed...
Just curious...was anyone here complaning that their crankset was not stiff enough? I mean, what are we talking about here? .00001mm deflection of a crank arm at 500ft/lbs of pressure? (not the numbers Velonews used I am sure)
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What if the Hokey Pokey is what it is all about?