Re: [CR]"Three arm" brake caliper?

(Example: Racing)

Date: Wed, 24 Sep 2008 14:07:34 -0700 (PDT)
From: Jerome & Elizabeth Moos <jerrymoos@sbcglobal.net>
Subject: Re: [CR]"Three arm" brake caliper?
To: Classic Rendezvous <classicrendezvous@bikelist.org>, dddd@pacbell.net
In-Reply-To: <248036.42862.qm@web82307.mail.mud.yahoo.com>


I take it the one in the photo is the less expensive version then?  Did t he better one have a QR and/or a fancier barrel adjuster?  Were these int roduced within the CR timeline?

Regards,

Jerry Moos
Big Spring, Texas, USA


--- On Wed, 9/24/08, david snyder wrote:


From: david snyder <dddd@pacbell.net> Subject: Re: [CR]"Three arm" brake caliper? To: "Classic Rendezvous" <classicrendezvous@bikelist.org> Date: Wednesday, September 24, 2008, 1:43 PM

That caliper is a DiaCompe SC (self-centering). These were common on (exclusive to?) Bridgestone bikes.

There were two levels of finish for these calipers, which were paired with

non-aero DiaCompe levers. I've had both versions, and they always lacke d power with standard pads.

The hump houses a rocker link, which pivots in the "3rd arm" and is "socket ed" into the main arms.  The "3rd arm" is not really an arm, but rath er just a lever that is friction-coupled to the center bolt.  The hidden

rocker link is somewhat fragile plastic, somewhat resembling a 3-ball s egment of a bead chain, although is is quite rigid. The whole mechanism makes caliper centering fully automatic whenever the

brake is applied, which re-centers the "3rd arm" between the 2 real arms.

David Snyder Auburn, CA  usa

Jerry Moos wrote:

The only marking visible in the photo is "SC", although perhaps it is mar ked Japan somewhere making him state it is Japanese.  Though not real c lear in the photo, there are three caliper arms on this brake, with the bra ke shoe to the viewer's left attached to the middle one, which does not app ear to attach to the brake cable.

Never seen a Shimano like this, so I would guess it is probably made by Dia Compe. Sort of in the vein of the three pulley SunTour RD, I suppose.  I

would guess this was supposed to be the answer to dual pivot SP brakes. 

I'm guessing this brake was made in the early 80's near the end of the CR e ra, so dual pivots were not yet popular, but the Altenburger/ GB Symmetric

had been around for at least a decade by then.

Can anyone identify this brake?  I would speculate it is a mid-priced mod el because of the simple adjusting barrel (if original), the lack of QR and the apparent lack of anodizing.  Granted the same was true of the Weinma nn 500, an excellent brake IMHO, but the 500 was designed a couple of decad es earlier, and by the early 80's a fancier brake was expected by high-end

buyers.  But perhaps this same design was available in a fancier high-end
   model.