I call Bulls**t. I owned a 2008 Spec. Tarmac s-works sl with BB30 and I had to adjust the cracks all the time. I had to replace the breaings 3 time in less then 1 year. Stiffness is not as high as you think, Velonews did a comparision between all the different BB standards and they were real close to each other. That is why Look, Cervelo, Pinarello, and ect...still use the old standard.
wow, that sucks about your tarmac! what cranks did you have? and adjust cracks? that's not good, what do you mean?? did you have specialized's cranksets and bb bearings? i feel for you, as i would be pis*ed as well!
All i will say is that i read that article on velonews. we all know that velonews didn't do a good job in both there explaination as well as "research methodologies" sorry, but that's pretty much a fact, based on thier explaination of what they did or didn't do.
the stifness of the cranks, depending on the company that manufactures them, all fall within standards dictated by international import compliance testing procedures [ie. CEN,DIN, etc..] so to only see a margininal increase within the crank itself concerning stiffness is reasonable and justified.
i saw velonews also compared weight. that really doesn't matter to much, but is explained because of the larger diameter spindle. by increasing the diam, you can reduce wall thickness to adjust weight and maintain strength. in otherwords, it would be over kill to have a larger diameter spindle, and maintain the wall thickness, where of course weight would increase for the crankset as a whole.
what makes the bb30, or 86/92shimano standards stiffer, is the fact that the frame has to be accommodating bigger bearings i.e. bigger bb area, etc... which means an increase in the surface area. so, crankstiffness should be tested within a speciac frame, it's the entire assembly that really makes or breaks the perceived and actual stiffness we're talking about.
in deciding what to do for our bikes, buying and testing competators frames are a must, as well as adhereing to our own testing protocol and decison on what is stiff enough/or not, for our brand and what we want to see compared to our competition. most companies, i would hope do that. i know companies i have work at, we have always done this to ensure our marketing falls in line with what is true, not just what sounds good.
i definitely wouldn't use velonews as a valid source [disclaimer
i do read velonews, it's just this article was really terrible] as they do not have the experience, nor methodologies to back up soild results. but... that being said, Tour magazine, a german mag, has both the experience as well as the appropriate staff who's extremely versed in testing procedures, as well as are engineers, to conduct a valid test. they actually are the mag that everyone in the indusry looks to for real unbiased results, and to see how they stake up.
FYI: companies try sending Tour mag frames during their testing sessions to try and get real results that conform to what they want to see. but, luckily Tour mag's people don't publish those results. Tour mag got wise a few years ago because some companies were utilizing higher TOW carbon fibers, in otherwords cf that is higher in strength and modulus of elast., which are subequently extremely more expensive then standard HM cf's used in their standard bike's layup schedule. this was to actually fool Tour mag. now, Tour goes to online and to LBS to buy framesets and components to test off the shelf. this is great because it's representative of what is really being used, and what the test results would really be. it sucks when Tour mag shames a company by publishing what is real and contradictory, but hey we all learn from our mistakes, or hopefully do!
every company that doesn't perform well in their tests all have come back swinging the following year! it's good for business as it keeps we manufactures inline concerning our claims!
ok, sorry, i probably discussed more then what people would want to read, but i haven't even scratched the surface on this topic. oh, i know what i did forget, that was comenting on cervelo, look, etc.... you know, i can't speak for them, every company decides what is best for their brand. what i will say is that a companies tube shape selections help compensate for components they may or maynot be used on a bike. as well, new molds are expensive, and i understand why some companies are still waiting to see what becomes accepted.
but the premise of this thread was what are manufactures doing concerning headed or not headed towards specing bb30 or shimano's 86/92 standards versus iso and italian, and will this be something that more companies are starting to decide to do from both our companies pov as well as what i see at the shows from my competitors.
something else just occered to me, hell, if bigger is better, then the italian standard M36x 24tpi was well ahead of it's time compared to the iso or the now obsolete french standard.
have a great night! shane