Re: [CR] Brakes and flex


Example: Framebuilding:Norris Lockley

Date: Wed, 05 Jan 2011 17:29:21 +0000
From: M-gineering <info@m-gineering.nl>
To: Classic Rendezvous <classicrendezvous@bikelist.org>
References: <D27D31E1-60E1-4C2F-BDBD-FCCD546DDD7B@att.net> <F601EFD5D432488AA9808D5726D53E92@ownerd556865ac>
In-Reply-To:
Subject: Re: [CR] Brakes and flex


On 1/5/2011 4:11 PM, paccoastcycles wrote:
> What is referred to as cable stretch, that is, the need to take up some
> cable after any new set-up, is the settling in of cable housing ends
> into the ferrules, the ferrules into their respective homes, etc.
>
> Of the engineers here, I'd like to ask a question. If we were to have a
> cable that stretched, say two millimeters over the distance of a rear
> brake run, would the cable stretch just those two millimeters and then
> stabilize? And, if so, why wouldn't it keep stretching?
>
> At the Interbike show a few years ago, I happened upon the Sram booth
> where, unless I misinterpreted what I walked in on the middle of, the
> guy was telling his audience that Sram had studied cable behavior and
> that they do not stretch in the use they recieve on bicycles.

What you call stretching is probably the summation of: - Cable settling in the clamp (with some permanent deformation of the strands - Cable strands setling against each other, but that is mostly a thing of the past with current recalibrated cable. It might have been a real issue with the funny flexible inners from the past - Cable smoothing out and compressing the surface in the outer cable liner

Once the initial play and slack is taken up, liner wear will be responsible for most of the change in adjustment.

-- mvg

Marten Gerritsen
Kiel Windeweer
Netherlands