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

(Example: Framebuilders:Alberto Masi)

From: "Roman Stankus" <rstankus@mindspring.com>
To: 'Adam Hammond' <anhammond@gmail.com>, 'CR discussion list' <Classicrendezvous@bikelist.org>
Date: Mon, 6 Apr 2009 19:09:21 -0400
In-Reply-To: <ab11edd00904060956j6543f2ecx7e7c333a6f50cfc3@mail.gmail.com>
Thread-Index: Acm22KtO57jUB8FzTvC0ZcO06NZtbAAMbxlw
Subject: Re: [CR] BBs for TA Pro 5 Vis cranksarms: old vs. new, symmetrical or not, taper styles


Last year I spoke with Mike Barry about the compatability of TA cranks with bottom brackets - he said that they work with campy NR BB's fine. I still haven't set one up (TA) so I can't say from personal experience - but I know Mike has had a lot of experience with them over the years so I trust his advise. He never mentioned older vs newer vintage cranks. We all know that campy cranks changed dimensions slighly over 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 stretches here and there.

Roman Stankus Atlanta, Georgia USA
> -----Original Message-----
> From: classicrendezvous-bounces@bikelist.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 cranksarms: old vs.
> new,symmetrical or not, taper styles
>
> I posted this to the BOB list this morning, but thought CR
> people might be even keener at spotting the differences or
> similarities between the on- and off-topic TA cranks.
>
> Here is my question:
>
> 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 completely symmetric.
>
> I ran this setup on Fuji touring bike for a few months last
> year to test it out, and everything seemed in order. There
> wasn't much crankarm clearance on either chainstay (I was
> using a 135mm rear end and fairly beefy chainstays), but
> 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 question of symmetricalness. For it seems
> TA's older bottom brackets for Pro 5 Vis doubles were not symmetrical.
>
> Piece of evidence number one: this chart from Sheldon Brown's website:
>
> http://www.sheldonbrown.com/harris/images/ta-bb-axles.gif
>
> This suggests that the BB should be offset VERY slightly
> (1.5mm) toward the drive side.
>
> And this photo of a TA 344 axle (the very one 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
> longer...)
>
> 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 designed for asymmetrical? If I were to
> have mounted my TA cranks onto the aforementioned Fuji
> touring bike with one of the TA 344 axles, I would have had
> one crankarm 8mm out from the chainstay, and the other
> smacking straight into it.
>
> To throw a final crankarm into the spokes: I have heard
> various rumours that the new TA production is designed for
> JIS spindles (and that the Axix BBs use JIS spindles) --
> would this explain all the confusion?

>

> Confused,

>

> Adam