Dan,
I think you're exactly right. The original owner taped a small, typed chart to the top tube: 29, 35, 40, 51, 58 - 39, 47, 54, 68, 77 - 46, 56, 65, 81, 93
I like your suggestion of going with 50-45-28. Wonder if that Campag front changer can handle the 22T difference? I'm okay with using the new rings from Mike Kone/Boulder Bicycles, but would prefer an older style stamped logo on the outer. I'll keep looking . . . Thanks for the suggestion!
Best, Alex Moll Seattle, WA
On Jan 24, 2010, at 12:00 PM, <classicrendezvous-request@bikelist.org>
wrote:
> Message: 2
> Date: Sun, 24 Jan 2010 13:31:55 -0500
> From: Barb and Dan Artley <hydelake@verizon.net>
> Subject: Re: [CR] 1963 Jack Taylor Clear Coat, Now half step?
> To: Classic Rendezvous <Classicrendezvous@bikelist.org>
> Message-ID: <000c01ca9d23$81e587c0$2f01a8c0@danbarbpc>
> Content-Type: text/plain; charset="iso-8859-1"
>
> Alex,
>
> The thought that a 45 x 40 tooth chainring might not be original to
> the bike is probably correct, but the five tooth jump between the
> top two rings would be appropriate for a 14 - 32 freewheel using
> half step gearing. If you're not familiar with half step, it
> essentially allows very closely spaced gears on a five speed set up
> with a good low gear when combined with a granny, a good touring
> combination before 6, 7 or more cog sets became readily available.
> To maybe really weird you out a bit more, plotting a half step set
> of gears on semi-log paper would show you just how cool the gear set
> really is.
>
> A half step freewheel would be 14, 17, 21, 26, 32. Even though
> jumps are wider for each gear, the change feels exactly the same at
> your foot. A standard five speed 14 - 32 would have a slightly
> different combination of gears, which for the life of me, I can't
> remember the combinations since mine are all set up as half step.
> The five tooth difference in front would make a perfect jump to the
> middle of any gear change in the back.
>
> Sooo ... Perhaps instead of just a 50 toothed outer ring, you may
> wish to also find the 45 tooth middle ring. A 32 inner ring would
> still give you a 1:1 or 27" gear. A 28 toothed inner would work out
> to approximately a 23" gear that would allow you to climb just about
> anything, even with a heavy load. And if you do plot the gears out
> on semi-log paper, you'll see exactly what inner would get you a
> perfect overlap of gear too. I believe those chainstay mounted
> Cyclo's will handle a really wide range of gears, though I admit to
> only getting to ride a poorly adjusted one once at a previous
> Cirque. Just wish my big feet didn't keep banging agains the
> derailleur mount! It's a beautiful bike and Taylors just have a
> lovely ride. Hope you ride it enough to really enjoy it.
>
> Happy trails,
>
> Dan Artley in Parkton, Maryland USA