The tiny bolt circle on the Pro 5 Vis crank often results in the larger outer chainrings bending outward. Having a little ramp there would help to prevent that.
Back in the good old days, when I sold those for touring, I tried to keep the outer chainring no larger than 46 teeth which was stiff enough to not bend outward.
Peter Jon White Peter White Cycles 24 Hall Rd. Hillsborough, NH 03244 603 478 0900 Phone 603 478 0902 Phax http://www.PeterWhiteCycles.com
> its a reasonably common arrangement on schwinn sports tours, and some
> other low price touring bikes from the 70s...
>
> the shift plate is bolted flat against the outer chainwheel, at the
> "criterium" pattern bolt circle, and the rest of the chainwheels are
> standard spacing.
>
> -joel
>
>
> >I haven't seen that arrangement before. I wish there were a shot
> >from the "top," so one could see ring spacing. I suspect it is an
> >assembly error, and two outer chainguards were used. (Or maybe
> >somebody had a very narrow chain fall in between the two rings?)
> >These cranks are very versatile, and all kinds of combos are
> >possible...
> >
> >Maybe somebody else knows more?
> >
> >Jan Heine, Seattle
> >
> >>
> >>------------------------------
> >>
> >>Date: Mon, 28 Apr 2003 22:09:24 -0700
> >>From: "Brandon Davis" <art_52@hotmail.com>
> >>To: <classicrendezvous@bikelist.org>
> >>Subject: [CR]Odd TA "inner" chainguard on eBay
> >>Message-ID: <Sea1-DAV57Q8AZndKaQ00000ad4@hotmail.com>
> >>References: <CATFOODfwfbs0yV8a5c00002296@catfood.nt.phred.org>
> >>Content-Type: text/plain;charset="iso-8859-1"
> >>MIME-Version: 1.0
> >>Content-Transfer-Encoding: 7bit
> >>Precedence: list
> >>Message: 19
> >>
> >>I came across this on eBay (but, of course), and wondered if anyone 1)
had
> >>seen anything like it before, and 2) would explain the raison d' tre of
it:
> >>
> >>T A old style triple crank right arm Item # 2172317848
> >><http://ebay.com/<blah>
> >>
> >>If you look closely at the two pictures, you'll see that there is an
outer
> >>chainguard (which is not all that unusual). But look a little closer,
and
> >>there's another(!) "chainguard" on the middle ring.
> >>
> >>This setup seems quite odd to me, at least ...but I figure one of the CR
> >>list experts can/will enlighten me.
> >>
> >>In correspondence with the seller, he didn't know what it was for
either;
> >>he'd acquired the crankarm & rings as shown, as part of a lot.
> >>
> >>--- brandon davis ---
> >>-- sacramento, ca --
> >>------------------------------
> >>
> >>_______________________________________________
> >>
> >>
> >>End of Classicrendezvous Digest, Vol 4, Issue 100
> >>*************************************************
> >
> >_______________________________________________
>
>
> --
> joel metz : magpie@messengers.org : http://www.blackbirdsf.org/
> bike messengers worldwide : ifbma : http://www.messengers.org/
> po box 191443 san francisco ca 94119-1443 usa
> ==
> i know what innocence looks like - and it wasn't there,
> after she got that bicycle...