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From: AMuzi <am@yellowjersey.org>
Newsgroups: rec.bicycles.tech
Subject: Re: RE: Re: Fine Tuning Shifting
Date: Wed, 14 Aug 2024 16:07:01 -0500
Organization: Yellow Jersey, Ltd.
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On 8/14/2024 3:35 PM, cyclintom wrote:
> On Tue Aug 13 17:47:38 2024 Jeff Liebermann  wrote:
>> On Thu, 25 Jul 2024 19:58:53 GMT, Tom Kunich <cyclintom@yahoo.com>
>> wrote:
>>
>>> I have a continuing problem with the shifting goin out of adustment. In one case the right shifter wire partially broke from my over-tightening it but in the other three cases I've had to mark it down to cable stretch which Andrew says doesn't exist. But the wires did not move and the shifting moved towards shifting into a faster gear. I can only assume that wire layup tightened up a little and showing those symptom.>
>>
>> 1.2mm galvanized cable (shifter cable):
>> 120 kg  (265 lbs) min breaking load.
>>
>> 1.6mm galvanized cable (brake cable):
>> 220kg (485 lbs ) min breaking load.
>>
>> <https://en.wikipedia.org/wiki/Working_load_limit>
>> I don't know the safety factor, but my guess(tm) is about 5 for the
>> brakes.  That puts the maximum load for the brake cable at:
>>     485 lb / 5 = 97 lbs
>>
>> I don't know what you're using for a shifter or brake level.  The
>> mechanical advantage can't be much.  This covers brake lever
>> mechanical advantage, but not shifter:
>> <https://www.toolonpyora.fi/post/mysteries-of-the-cantilever-brake-what-about-the-brake-levers>
>> For brakes, my guess is no more than 37 lbs with a mechanical
>> advantage of about 6.  Therefore, with a strong grip, you might be
>> able to tension the cable to:
>>    6 * 37 lbs = 222 lbs
>>
>> We lose grip strenth as we get older.  For 65+, the typical RH grip
>> strength is more like 21 lbs
>> <https://godsofgrip.com/pages/average-hand-grip-strength>
>>    6 * 21 lbs = 126 lbs
>>
>> The shifters will be very different numbers, but I don't have enough
>> info handy to work those out.
>>
>> Pulling on the brake cable with 126 - 222 lbs is more than the 97 lbs
>> required for the minimum breaking load.
>>
>> <https://testbook.com/physics/stress-strain-curve>
>> -- 
>> Jeff Liebermann                 jeffl@cruzio.com
>> PO Box 272      http://www.LearnByDestroying.com
>> Ben Lomond CA 95005-0272
>> Skype: JeffLiebermann      AE6KS    831-336-2558
> 
> 
> 
> 
> What does galvanized wire have to do with anything? Campagnolo uses finer wire twisted more turns per inch. Shimano inners use thicker individual wires with fewer turns. You know note of this and make comments that have nothing whatsoever to do with it becayse you don't know anything about bicycles.
> 
> Shimano derailleurs have a higher spring tension and Campy has lower spring tension. So if you use Campy wires on a Shimano setup it will pull the wires tighter.
> 
> Andrew apparently missed this fact and that he was talking about crappy setup which you might consider correct IF you're using one Campy wires on Shimno. This was my problem with three or four adjustments to reach equilibrium. This was continually commented on by Krygowsky because he is a freewheel friction shifter who CANNOT HAVE THAT PROBLEM. But he can comment on things he knows nothing about. Sort of like Liebermann.
> 
> I am willing to believe that Flunky raced friction shifters but that his memory of that is so poor that he doesn't even remember how he did it. On the beginning of a YouTube video (about a race Lemond won) there was a HEADER showing a freewheel frcition setup going through the gears and there was perfectly distinct pauses between gears as the power was shut down. What was also distinct about that video was that racers did NOT follow as closely as they do now because of that large variation in power causing accelerations to be rather spotty.
> 
> I have had it with stupid asses that know nothing about the subject shooting their mouths off about it. Liebermann is the most coommon contributor to stupidity. Krygowski is easily the second. No other person in the world would pretend that it is stupid to wonder what meansurement system that Torx fittings are designed under. Krygowski is too dumb to know that you cannot have a standard without measuremnents. Questioning if those standards are English or Metric or either is beyond his ability to think.
> 
> Flunky just talks ahbout crap that he doesn't know about. Notice how he could not answer how you measure the length of a wire electronically? That's because he personally doesn't know how to use an oscilloscope. Which comes as no

We do not see any functional difference between Campagnolo 
and Shimano brand gear wires (used in the appropriate lever 
of course).  We also use Campagnolo tandem (3 meters) gear 
wires on XL road bikes with Shimano equipment without any 
foibles or failures.

In fact, gear wires in modern road systems with correct 
casing, ferrules and setup are notably reliable. The 
failures are nearly all at the lever, where the wire wraps 
on its capstan. This is not an issue with flat-bar levers BTW.
-- 
Andrew Muzi
am@yellowjersey.org
Open every day since 1 April, 1971