On May 30, 7:03 am, jim beam <
[email protected]> wrote:
> Qui si parla Campagnolo-www.vecchios.comwrote:
>
>
>
> > On May 29, 9:49 am, Jay Beattie <[email protected]> wrote:
> >> On May 29, 5:54 am, jim beam <[email protected]> wrote:
>
> >>> Qui si parla Campagnolo-www.vecchios.comwrote:
> >>>> On May 28, 9:59�pm, RS <[email protected]> wrote:
> >>>>> Square taper to octalink to ISIS to outboard bearings. �Do the outboard
> >>>>> bearings really make for a useable and/or noticeable difference overolder
> >>>>> systems? � Would especially like to hear from anyone who switched out
> >>>>> an ISIS or Octalink for a current outboard bearing type of crank.
> >>>>> thanks
> >>>> Outboard bearings was the 'solution' to the poor design Octalink,
> >>> sorry peter, that's not an accurate assessment - octalink is an
> >>> excellent design solution to a very real problem. while it may not have
> >>> been an everyday occurrence, the physical design of square taper renders
> >>> it more susceptible to fatigue than the larger pipe spindle designs:
> >>>http://pardo.net/bike/pic/fail-001/spindle-fail-001.jpghttp://pardo.n....
> >>> it's simply a function of skin stress. larger diameter means lower
> >>> stress and thus less fatigue. thus, octalink showed the way to
> >>> solution. continuing from that, the next step has to be outboard
> >>> bearing because it's not possible to get a larger spindle inside a
> >>> standard bb shell and still have bearings inside as well.
> >>> all the bleating about the supposed "poor design" of octalink was
> >>> generated by jobst brandt who, somewhat typically, failed to notice one
> >>> of its small but very important design features and thus he criticizes
> >>> octalink for a failure mode that doesn't exist.
> >>>> followed by the poor ISIS. Nether were an improvement to square taper,
> >>>> just something 'new' started in 1997 by shimano. Being the gorilla,
> >>>> Octalink(that shimano never licensed BB wise), waned and shimano
> >>>> started outboard bearings, and all crank makers came on board with,
> >>>> Campagnolo being the last to market it. Octalink and ISIS answered no
> >>>> question, solved no problem with regards to square taper but you see
> >>>> what the market has done. BB30 is being embraced by frame makers,
> >>>> along with 1 1/4 and 1.5 inch lower headtubes because it makes it
> >>>> easier(cheaper) for frame makers to hook great big tubes to bigger
> >>>> tubes(BB shell and headtube). Crank makers that are embracing BB30 are
> >>>> assuming all frame makers are going to go that way, but we'll see. FSA
> >>>> hasn't seen a new idea it didn't like as shown by their speed in
> >>>> making an ISIS, then outboard, then BB30 crank. A gent from FSA once
> >>>> told me right after they started the outboard bearing design they
> >>>> would rather copy than create.- Hide quoted text -
> >> It is interesting that all of those are '70/80s Campy NR spindles from
> >> open bearing BBs. Are there pictures of Shimano cartridge BB square-
> >> taper spindles failing? Not saying they didn't, but I never saw one
> >> fail -- just had bearings go south after many, many miles of riding.
>
> >> I killed ISIS (and to a lesser extent Octalink) bearings in short
> >> order -- within a few thousand miles. The latest one was an expensive
> >> FSA -- but FSA would not touch it because the company had abandoned
> >> ISIS. As it turned out, I had broken the ISIS crank, too. The female
> >> insert in the CF arm had cracked all to hell. FSA did not have a
> >> replacement arm because, again, they had abandoned ISIS. I now have
> >> expensive key chain fobs. -- Jay Beattie.
>
> > Not to mention that there were many thousands of square taper Campag
> > BB spindles and the percentage of breakage was low. I didn't keep the
> > 3 octalink BBs that I replaced that broke in the center of the spindle
>
> you really should have - these are the first i've ever seen reported.
> next one you get, please post here - i'd love to examine it.
>
> > nor the octalink cranks that failed from 'lash, mostly MTB ones where
> > a rider gets airborne and then lands. To state that Octalink and ISIS
> > was produced by shimano and others to fix the huge square taper
> > breakage problem of Campagnolo is silly.
>
> one more problem with square taper and "lash", i've had a number of them
> work loose over the years. and on many occasion i've stopped to help
> mtb riders with that problem too. i've never had an octalink crank work
> loose and i've never had to stop and help anyone else with a loose
> octalink crank either.
Square tapers will work loose if not properly installed pretty
quickly, not over the years. If they are properly installed, they will
not work themselves loose. Octalinks and Isis have only been sold for
two to three years and then they were discontinued. I am sure that if
they are properly installed, they will last for a long time. However,
too many reports of failures lead to them being redesigned. Square
tapers have been in existence for several decades, so comparisons in
terms of durability are not adequate. Since people would report
failures w/ octalink and the did not offer an incredible advantage
over square taper, they were abandoned soon.
Regarding people that you will find with loose BBs, that is likely in
cases were people just purchased a new bike that was not properly
adjusted, or people who recently had a tuneup and the bb had not been
properly tightened. That, or they rode five times in five years. If
you use plumbers tape on the crack bolts, the don't work themselves
loose even if they are poorly tightened.
A problem that I would find with square tapers were on the Italian
threaded ones. They required that the fixed cup would turn in a
direction that would work itself loose unless it was really tight in
the BB shell. This requires either a fancy and expensive Hozan tool
that held the cup wrench in place to tighten the fixed cup, or a home
made devise that would do the same function. Most shade tree mechanics
and a bunch of bike shops had neither. This would lead new Italian
threaded bike BBs to work themselves loose.
Andres
