[CR]More Musings on TA Cranks and WTT

(Example: Framebuilders:Doug Fattic)

Date: Tue, 2 Oct 2007 08:57:08 -0700 (PDT)
From: Jerome & Elizabeth Moos <jerrymoos@sbcglobal.net>
To: classicrendezvous@bikelist.org
In-Reply-To: <436691.39717.qm@web82212.mail.mud.yahoo.com>
Subject: [CR]More Musings on TA Cranks and WTT

To elaborate further on the recent "variety pack" of TA stuff I bought from a list member, it reminds me that TA carried versatility and variety almost to the point of becoming a vice. The 152 BCD Criterium rings I acquired in this purchase are the type with which the inner ring bolts to a 152 BCD circle in the outer ring. But I also have a Criterium "Adapter" with no teeth itself, which bolts to the arm, with both rings bolting to this adapter. The possible range of rings is the same either way, so I'm puzzled as to why TA felt it necessary to implement this bolt circle two different ways.

In addition, I have in this purchase two very small Cyclotourist inner rings, a 28T and a 26T. The 28T uses the Cyclotourist inner circle, bolting to the outer ring. But the 26T uses the very small circle used to bolt the outer ring to the arm. Anyone ever notice this before? How small did TA go with these rings? And what sort of bolts would this take? One presumes, when using a 26T inner, which would almost certainly be a triple, unless it was a 4-ring crank, which I believe did exist, the middle ring would bolt to the outer, while both the outer and the inner would bolt to the crank arm using long bolts. Could the normal triple chainring bolts be used to attach outer and inner rings to the arm? If not, what bolts did one use with a 26T inner ring?

Finally, this lot included two NOS left arms, old style with foil stickers, one 150 mm and one 160 mm. Suitable of children or small adults. Anyone have 170mm left arms they would care to trade for these?


Jerry Moos Big Spring, TX

Jerome & Elizabeth Moos <jerrymoos@sbcglobal.net> wrote: Actually, not quite accurate. I just today received an assortment of TA arms and rings from another list member. Included was a pair of 152 BCD Criterium rings. This the bolt circle for attaching the inner ring to the outer. The outer ring attaches to the arms with the same small circle as Cyclotourist. I was surprised to find that the inner ring is a 43T. I thought 44T was the smallest you could mount on a 151 BCD circle, let alone 152 BCD. But an old Sutherland's does list TA Criterium as 152 BCD with 43T minimum. I do note that the bolt hole is drilled about as close to the teeth of the 43T ring as I have ever seen on a factory ring. Also, TA Criterium used a 7.2 mm bolt hole as opposed to Campy 10 mm, which provided just a bit more distance between the hole and the teeth. Just enough, it seems, to go one tooth smaller on the TA cranks.


Jerry Moos Big Spring, TX

Donald Gillies wrote: Re: Campy chainring, 148bcd

I am thinking this sounds like an october fool's joke, or maybe you are looking for 151bcd. One of our San Diego LBS's (I think Cal Coast Bikes) has campy 151bcd rings, although 42 is not humanly possible in track pitch. In general, you get about 1 BCD for every 3.4 mm of chainring. So, for a 148 bcd crank, minimum would probably be 43T, and for 151 bcd, minimum is about 44T.

In 144 bcd, NOS 42T campy rings are still quite available in 3/32 (like the guy at the local san diego high tech swap meet 4 months ago). Two possible workarounds :

(a) If you really cannot find a 43/44 ring in 148, maybe there was a place in Japan that would custom-make one for you. You might even be able to get 42T if it's truly 148 bcd - just barely. I think that if 148bcd exists, campy probably didn't make it because this size would likely put wear on the spider. Unfortunately price is probably about $130 shipped.

(b) If it really is 148 bcd, perhaps you could find a smaller ring (such as SR 118 bcd) and do a number on it with a dremel tool and some files. A little 30-minute number. I love my little dremel. When it spins up to 22,000 rpm, all the aluminum parts in my garage bow down and pray for salvation ...

- Don Gillies
San Diego, CA