Re: [CR]TA chainring bolts

(Example: Framebuilders)

Date: Fri, 26 Oct 2007 22:21:21 -0700 (PDT)
From: "Fred Rednor" <fred_rednor@yahoo.com>
Subject: Re: [CR]TA chainring bolts
To: classicrendezvous@bikelist.org
In-Reply-To: <450527.35151.qm@web82215.mail.mud.yahoo.com>


> OK, TA mavens, here's another question about the TA cranks
> almost universally called CycloTourist, even though I guess
> the official name was Pro 5 Vis.
>
> I've been picking up chainring bolts on eBay whenever I
> find them at a good price, and I've noticed it's hard to tell
> the bolts that attach the rings to each other from those that
> attach the large ring to the crankarm, except by the length
> of the bolts. It appears that the nut/sleeve, may be the
> same in either case. Is this correct?
> Regards,
> Jerry Moos

Jerry, The sleeve nuts that are used for attaching the outside chainring, or an Adapteur, to the crankarm are 5mm long. That's the length of the sleeve, excluding the thickness of the head. Also, the outside surface of the head is flat, with a groove bisecting that surface. These sleeve-nuts are part of the #25 bolt set. The sleeve section of the nuts used with the #62 and #64 sets is 6mm long. On modern versions of these, the outside of the head is _slightly_ domed and takes a 5mm hex key. If I recall correctly, on older versions the outside surface of the head is absolutely flat, and perhaps takes a different sized hex key. The #64 set includes spacers, whereas the #62 set has none. That's because the #62 set is meant for mounting 2 chainrings to an Adapteur, in which case the Adapteur itself acts as spacer between the 2 chainrings. If you're mounting a single chainring to the Adapteur, you use the same shorter sleeve nuts as those in the #25 set - except, of course, you need 6 of them rather than 5. There's an official TA reference number for these sets. There might even be 2 different sets - one with the beautiful dome headed bolts and one with the ubiquitous flat headed bolts. Either way, if you're mounting a single 3/32" (i.e. the 2mm) chainring to the Adapteur, you'll need to use a washer between the bolt head and the chainring's surface. It's a long story, and probably seems unnecessary without a close inspection of the individual pieces, but - trust me - you need to do it. Anyway... the sleeve nuts for for triple chainring setups are much longer (10mm?) and I think you also use a longer bolt with those sets. My small collection of nuts and bolts for TA triples is in another box that isn't so easily located, so I can't write as emphatically about those. Well that's it for tonight! Fred Rednor - Arlington, Virginia (USA)

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