Re: [CR]Widest possible Campy NR ratio range: Depends.

(Example: Events:Cirque du Cyclisme:2002)

Date: Sun, 18 May 2003 16:14:11 -0400
From: "HM & SS Sachs" <sachs@erols.com>
To: Peter Jon White <PeterJonWhite@peterwhitecycles.com>
Subject: Re: [CR]Widest possible Campy NR ratio range: Depends.
References: <3EC7DEBD.50906@erols.com> <118c01c31d74$a3060b40$6501a8c0@office>
cc: classicrendezvous@bikelist.org
cc: classicrendezvous@bikelist.org

The key difference between the "steel" record and the Gran Sport is the design of the pulley cage. On the GS, the pivot point is on a line connecting the pulley axles, halfway between them. On the Record, three things change: First, the pivot point moves closer to the top pulley than the bottom one. Second, the pivot point is considerably forward of the line between the two pulley axles. Third, the pulleys are about 2 - 3 mm further apart on the Record.

So, the Record will wrap a bunch more chain. I don't have time to mount and compare them, but with each hitting its stop, the Record top pulley is further forward, so it would wrap more chain at the limit. Together, the differnces add up. The GS is marked "da 14 a 26 denti" on its back; while the Record is just market (in larger numbers) "13 - 36" That is not a typo. Thirteen to thirty-six.

I found no guide stamped into the Nuovo Record, and don't have a SuperRecord. But, here's a bit more grist for the mill: Sport (single pulley): "da 16 a 22 denti" Gran Turismo (boat anchor): "13-36---36-54"

I don't think I'll try using a 36 with my Record, but I'm trying to remember whether I tried the Suntour 14-32 and 14-34 "Perfect" and "ProCompe" freewheels.

Your mileage may vary, but the trip itself is the goal..

harvey sachs mcLean va

Peter Jon White wrote:
>>BTW, the Record is comfortable with the 13 th top, but I could never get
>>
>>
>the preceding Gran Sport to work with anything smaller than 14: just plain
>skipped, no matter what chain or spring tension I used. But, in its
>defense, it was marked "14 a 26" denti (or something like that).
>
>
>>harvey sachs
>>
>>
>
>That's odd. Did the Gran Sport not pivot as far forward as the NR? If so, it
>wouldn't wrap as much chain, all other factors equal, and without enough
>chain wrap, the chain's going to skip.
>
>Peter Jon White
>Peter White Cycles
>24 Hall Rd.
>Hillsborough, NH 03244
>603 478 0900 Phone
>603 478 0902 Phax
>http://www.PeterWhiteCycles.com
>
>http://www.mises.org