Control cable quality.

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Control cable quality.

Postby SPRIDDLER » Mon Jun 24, 2019 12:15 pm

The ease of and improving clutch action and front brake effectiveness is often mentioned on here with comments on the importance of fitting good quality cables.
Whilst faffing about tidying up the shed I came across a dozen or more cables that I'd bought whilst experimenting with a combined brake/clutch adaptation for my Matchless. I was struck by the difference in quality between the conduits (the spirally wound outers) of the cables from autojumbles (5.2mm dia.) and the more expensive and robust ones (7.1mm dia.) from in this case, Venhill Cables and which may be of interest to others. The inners are similar but the outers and the end ferrules on the Venhill cables are far more substantial.

Control cables dims..jpg

The outers of the less tightly wound and cheaper cables tend to compress throughout the whole length of the cable giving a spongy feel to the front brake action and in the process of compression friction is generated on the inner, especially at bends. Note how the flimsy ferrule on the little used cable below has already begun to compress/crush the outer due to the spiral outer compressing.....O.K. for a light throttle cable but not robust enough for a front brake.

Control cable ferrule.jpg
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Re: Control cable quality.

Postby Antoni » Mon Jun 24, 2019 2:52 pm

My experience with the inner cables is worth mentioning here. Done 10 thousand miles with the throttle cable that was on the bike. I've had four failures (I keep a log of what's done to the bike). Each time the throttle cable failed raggedly about 3/4" down from the twistgrip nipple. That's where it is repeatedly bent in a gentle radius around the twistgrip 'pulley'.

It reminded me of a design failure at work. After failures we found by experiment that the lightweight high tensile steel cable chosen was not after all suitable for the pulleys the cable had to go around. They failed early in bending. With a beter steel alloy chosen the problem went away.

I just bought some new throttle inner and outer to make up a repalcement for the bike's throttle cable but it's anyone's guess whether it will be better or worse - but at least it's different. It isn't possible to get exactly the cable alloy you want in small quantities so it's pot luck...

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Re: Control cable quality.

Postby GOLDSTAR » Tue Jun 25, 2019 7:04 am

I tend to make my cables and when possible go up at least a size with front brake and clutch cables, my view is similar to Sprids the stronger the outer the less compression when used. kind regards

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Re: Control cable quality.

Postby 56G80S » Tue Jun 25, 2019 6:20 pm

Sprid is correct. I bought some JJ Cables (although the second time through Steve Surbey at AMC Classics) and they were much better than those I had been using and that is particularly noticeable on the front brake. I also re-work cables and fit my own nipples (oo er) and there are other threads about that. I was surprised when trying to remove a nipple from an old cable for re-use and it simply melted! Not brass at all.

But if, unlike me, you do very low miles and cost is a factor maybe that's not so important......................

Johnny B

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