Re: [CR] Brakes and flex


Example: Framebuilders:Brian Baylis

From: "paccoastcycles" <paccoastcycles@sbcglobal.net>
To: "Ken Freeman" <kenfreeman096@gmail.com>, "John Betmanis" <johnb@oxford.net>
References: <1AF44DEDBB574D42885E6BF8375640B8@gateway2v8e13w> <AANLkTimpQiQSWYRYh5k=gnt7Jhrsce27pTYKCz58jH6B@mail.gmail.com> <4D23943A.4070906@oxford.net> <AANLkTimFV1Vmrehw6bisGw_bkZgraaCgqvZ=qX-TiTsD@mail.gmail.com>
Date: Tue, 4 Jan 2011 22:10:44 -0800
Cc: classicrendezvous@bikelist.org
Subject: Re: [CR] Brakes and flex


John Betamus, thank you for making me not feel alone in the world of bicycle mechanics with regard to cables not stretching. I'm always shagrined (not crestfallen) when I hear someone who says their mechanic said this or that about cable stretch. I think of it this way: If you try to hang a car from a bridge with a bicycle cable, it will stretch...and then break. But the forces we put on these cables are not stretching them.

Chuck Hoefer
Pacific Coast Cycles
Oceanside, Ca.


----- Original Message -----
From: "Ken Freeman"
To: "John Betmanis"
Cc:
Sent: Tuesday, January 04, 2011 6:08 PM
Subject: Re: [CR] Brakes and flex



> I've made a lot of improvement in the feel of previously bad brakes by
> replacing with modern inner and outer cables, carefully terminated by
> filing
> and with ferrules.
>
> On Tue, Jan 4, 2011 at 4:42 PM, John Betmanis <johnb@oxford.net> wrote:
>
>> On 04/01/2011 3:53 PM, Harry Travis wrote:
>>
>> Please someone, show me that new design stainless steel cables stretch
>>> less
>>> than old-skool zinc-plated ones (any more than bicycle chains
>>> "stretch.")
>>> Which is to say: Show me that they measurably stretch at all, as against
>>> simply having the ends bed and the housings move.
>>>
>>
>> Springiness or lost motion in brake cables is no more due to "stretch"
>> than
>> a worn-out chain is "stretched". It's the housing that's the culprit when
>> it
>> appears to "compress". If there is excessive clearance between the inner
>> cable and the housing, the housing will "buckle" in a series of "S"
>> curves
>> before any serious tension reaches the brake caliper. Moreover, if the
>> housing is made of round section wire rather than rectangular, the coils
>> can
>> also "slip" allowing more "compression". I believe the reason the better
>> modern cables have less "stretch" is due to better design and closer
>> tolerances.
>>
>> --
>> John Betmanis
>> Woodstock, Ontario
>> Canada