Re: [CR] Dura-Ace Timeline / Primative "front indexing"

(Example: Production Builders:Peugeot)

From: "dddd" <dddd@pacbell.net>
To: "Classic Rendezvous" <classicrendezvous@bikelist.org>
References: <20060809201056.54254.qmail@web82211.mail.mud.yahoo.com>
Subject: Re: [CR] Dura-Ace Timeline / Primative "front indexing"
Date: Wed, 9 Aug 2006 14:20:54 -0700
reply-type=original

The sprung derailer cable anchor arm, which endured well into the '90's, was also a functional way to prevent cable (or pullley?) damage or misadjustment from forced lever movement, either by a rider or ill-intentioned passersby. It also functions nicely when riding very slowly in awkward difficult confines, as on trails. I can reach down, slap a downshift, and the sprung lever alows the shift to occur more normally a moment later and with the final resting position of the lever more likely to be on-center with the chosen cog. I never noticed this until later riding a bike without this feature, and having to push the lever for a longer duration when pedaling slowly. This might even benefit a racer when remounting after a crash or cyclocrossing, however my tourer's Light-Action derailer was a cheapy and did release the sprung cage pivot straight into the spokes during a cyclocross race, wreaking multiple havoc while I surrendered a hard-fought second-place on the final lap during last season's series. I had ridden my touring bike to the race for a change of pace, but couldn't ride back. Even the wheel got mighty messed up, though the steel Miyata frame resisted the explosion impressively. Some OT versions are labeled "Light Action", some not, and I believe there's still a version or two offered today. My current 1992 cyclocross racer has one curiously labeled "CX500", tho this OT gruppo was intended for hybrids. Most of Shimano's stuff seems pretty well thought out and I don't always appreciate their designs until years later, as their subtle design goals become apparent after I've used and worked on the stuff for a while. I've often wished that my triple-ringed Trek 710 had an "indexed" travel stop on it's front Aero shift lever to keep from over-downshifting to the middle ring during competitive riding amidst sharp rolling hills. I have repeatedly pondered such a device while riding, possibly consisting of a tiny frame-mounted, spring-loaded lever leaning against the front of the shift lever, and that could be flipped away from the lever when a shift to the smal ring was actually needed, which is almost never in that bike's routine. Couldn't you imagine a Rene Herse with something like that, an elegantly skulpted and chromed spring-loaded dog-leg doo-dad?

David Snyder Auburn, CA usa

Jerry Moos wrote:
> Not only that, but they need an indexed front derailleur. The comment I
> remember from years ago is: "Indexing a front derailleur is like indexing
> a light switch."
> Sheldon Brown wrote:
>>These derailers [Lark & Eagle] also featured a nifty Shimano invention
> that is no
>>longer available, unfortunately. The anchor bolt was mounted on a
>>spring loaded arm, so you could "preselect" a lower gear by yanking
>>back on the lever if you accidentally got stopped in too high a gear.
>>As soon as you would start to pedal, the spring would shift the
>>derailer down to whatever position you had selected.

John Betmanis <johnb@oxford.net> wrote:
> Good luck with that today, when people need index shifters to find a gear
> while on the move, let alone stopped! ;-)