Re: [CR] BBs for TA Pro 5 Vis cranksarms: old vs. new, symmetrical or not, taper styles

(Example: Framebuilding:Technology)

Date: Mon, 6 Apr 2009 18:49:58 -0700
From: "Fred Rednor" <fred_rednor@yahoo.com>
To: <Classicrendezvous@bikelist.org>
Subject: Re: [CR] BBs for TA Pro 5 Vis cranksarms: old vs. new, symmetrical or not, taper styles


A few months ago, I measured the end of the tapers on 2 different vintage T A bottom bracket spindles. One was a model 344 and the other a model 314. In both cases, size was exactly midway between ISO and JIS.

That migh t explain why the TA cranks seem to work well with different styles of bott om brackets.
    Fred Rednor - Arlington, Virginia (USA)
> Last year I spoke with Mike Barry
> about the compatability of TA cranks with
> b ottom brackets - he said that they work with  campy
> NR BB's fine. I s till
> haven't set one up (TA) so I can't say from personal
> experienc e - but I know
> Mike has had a lot of experience with them over the year s
> so I trust his
> advise. He never mentioned older vs newer vintage cranks.
> We all know that
> campy cranks changed dimensions slighly ov er the years.
> Hope this helps.
> One of these days, I'm going to set up that TA double
> compact crank - I have
> really grown to like that gearing on my regular modern
> ride. It works great
> in the endless up
   and down roads of north Georgia where you
> can pretty much
> count on
   around 1000' of climbing/hour around Atlanta with
> some steeper
> str etches here and there.
>
> Roman Stankus
> Atlanta, Georgia USA
>
> > -----Original Message-----
> > From: classicrendezvous-bounces@bik elist.org
>
> > [mailto:classicrendezvous-bounces@bikelist.org]
> On
   Behalf Of
> > Adam Hammond
> > Sent: Monday, April 06, 2009 12:56 PM
> > To: CR discussion list
> > Subject: [CR] BBs for TA Pro 5 Vis cran ksarms: old vs.
>
> > new,symmetrical or not, taper styles
> >
>
> I posted this to the BOB list this morning, but
> thought CR
> > peo ple might be even keener at spotting the
> differences or
> > similari ties between the on- and off-topic TA cranks.
> >
> > Here is my quest ion:
> >
> > I have in my possession one of the newer TA Pro 5 vis
>
  
> > cranksets -- produced in 2007. I also have a TA Axix
> BB,
> >
   which is from the same year. The BB is 116mm wide,
> which I
> > have
   always heard is the correct width for TA
> doubles.
> > This BB is com pletely symmetric.
> >
> > I ran this setup on Fuji touring bike for a
   few months
> last
> > year to test it out, and everything seemed in o rder.
> There
> > wasn't much crankarm clearance on either chainstay ( I
> was
> > using a 135mm rear end and fairly beefy chainstays),
> b ut
> > things seemed more or less centred.
> >
> > I was testing it
   for the still-forthcoming custom
> frame I
> > expect to arrive in a few months. In the meantime I've
> become
> > interested in this quest ion of symmetricalness. For it
> seems
> > TA's older bottom brackets for Pro 5 Vis doubles were
> not symmetrical.
> >
> > Piece of evide nce number one: this chart from Sheldon
> Brown's website:
> >
> > h ttp://www.sheldonbrown.com/harris/images/ta-bb-axles.gif
> >
> > This suggests that the BB should be offset VERY
> slightly
> > (1.5mm) towa rd the drive side.
> >
> > And this photo of a TA 344 axle (the very o ne
> specified for
> > TA doubles in the above diagram) seems to show an even
> more
> > significant driveside offset, though it is the same
> length as
> > my symmetrical Axix BB: 116mm. (It may be .5
> > lo nger...)
> >
> > http://picasaweb.google.ca/olivier.alonzo/Alcyon?feat =embedweb
> site#5311728504161556194
> >
> > My question basically
   is: did TA change their cranks
> for the
> > newer production runs to
   make them work with
> symmetrical BBs
> > when they used to be design ed for asymmetrical? If I
> were to
> > have mounted my TA cranks onto
   the aforementioned Fuji
>
> > touring bike with one of the TA 344 axl es, I would
> have had
> > one crankarm 8mm out from the chainstay, an d the other
>
> > smacking straight into it.
> >
> > To throw a f inal crankarm into the spokes: I have
> heard
> > various rumours that
   the new TA production is designed
> for
> > JIS spindles (and that th e Axix BBs use JIS spindles)
> --
> > would this explain all the confu sion?
> >
> > Confused,
> >
> > Adam
> >
> >
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