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Old 04-16-14, 08:09 AM   #1
RaleighClassic
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Brake cable grind

Hi!

I'm a new user, I've spent years learning stuff from other peoples posts, but can't seem to find anyone who's had my specific problem, so decided to do my first forum post.
I wonder if anyone can help. I recently bought a 23.5" 80's Raleigh Classic, complete 531 frame and forks as I decided my 25" Carlton was too big for me. The Classic came without brake cables, so I bought what I was reassured were jagwire cables and housing from ebay. After using for only a week, both the front and rear cables have begun to show signs of friction - when I brake, they make a horrible grinding noise and are hard to pull, and sometimes don't return fully.
The problem is definitely in the cables rather than the brakes themselves, which are Weinemann centre pull.
I didn't grease the cables when I put them in, as I had read that modern housing does not require it.
Has anyone encountered similar problems?
Is it possible that I have just been sold trash instead of real jagwires?

Cheers!
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Old 04-16-14, 08:24 AM   #2
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Odds are that it isn't friction within the cable, since they're lined and there's no way you could have worn through the lining that fast.

So the place to look is at the cut ends, and how they line up to the fittings. Often people cutting a housing end up curling the last turn in in the process, so the wire binds on it, so check that both ends are nice and clean with the hole unimpeded.

Then check that the cable run is nice and clean where the cable enters the levers and at the fittings, Any bends at this critical point will cause the wire to rub and bind. Also check that you used the correct ferules to ensure a good fit into the various fittings.

BTW- you didn't say, and I assume you bought kits, but if not, make sure you're not using index housing (the steel runs the long way, rather than like a coil spring). Using index housing in brakes is a serious no no for a variety of reasons.
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Old 04-16-14, 08:37 AM   #3
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Depending on the specific Jagwire cable set, both the cable exterior and housing interior are made of slippery substances, so you shouldn't be getting any grinding. In fact, even with older cables, if installed properly, lack of lube may make the brakes harder to apply, but shouldn't grind... Back in the day, I didn't always lubricate before assembly, and never got grinding.

I could envision a bad cut of the housing that could cause the metal used to strengthen the housing to scrape the cable... but you would have probably noticed this pretty quickly. You should explore any "interfaces" with cable to housing, barrel adjusters or cable guides to see where the problem is happening... Especially the front brake should be pretty straight forward to inspect, since there are only 2 points for a potential issue.
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Old 04-16-14, 01:07 PM   #4
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& low cost cable sets would perhaps not be using Die drawn slick cables , there you may have to buy the cable it self ,

But , of course, IDK what was ordered.. jag wire does offer those type of cables..

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Old 04-16-14, 03:01 PM   #5
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Quote:
Originally Posted by FBinNY View Post
Odds are that it isn't friction within the cable, since they're lined and there's no way you could have worn through the lining that fast.

So the place to look is at the cut ends, and how they line up to the fittings. Often people cutting a housing end up curling the last turn in in the process, so the wire binds on it, so check that both ends are nice and clean with the hole unimpeded.

Then check that the cable run is nice and clean where the cable enters the levers and at the fittings, Any bends at this critical point will cause the wire to rub and bind. Also check that you used the correct ferules to ensure a good fit into the various fittings.

BTW- you didn't say, and I assume you bought kits, but if not, make sure you're not using index housing (the steel runs the long way, rather than like a coil spring). Using index housing in brakes is a serious no no for a variety of reasons.
Jagwire's best cable kits do include index brake housing. FB, I am surprised to hear you say those aren't desirable. They have worked great in every side pull application I have used them on. Why are you opposed to them?
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Old 04-16-14, 03:19 PM   #6
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Jagwire's best cable kits do include index brake housing. FB, I am surprised to hear you say those aren't desirable. They have worked great in every side pull application I have used them on. Why are you opposed to them?
Long spiral (low helix) or so-called compressionless housing was developed for it's superior ability to transmit position rather than tension. It as long considered unsuitable for brakes for two reasons

1- at high compression load the ends will try to extrude through the conical bottom of brake fittings and ferrules. This is correctable with a proper ferule with a reverse conical bottom which forces the strands toward the wall rather than the hole.

2- and the more important reason, is the mode of failure. A high helix, aka spring coil has the coils sit on each other constrained by the wire passing through the middle. In the event of failure a single coil may (very rarely) over another, but in general the cable depends only on the steel for it's compression strength.

Compare with the long spiral where the strands run lengthwise. At high compression the strands want to buckle outward and are constrained only by the plastic cover. If the cover is cut, UV compromised, or otherwise damaged the cable will buckle under load bursting and failing completely. Given how brakes work, one can rest assured that this kind of catastrophic failure will happen at the worst possible moment, when brakes are most needed.

This is why long spiral housing was often marked "not for brakes"

BUT

Knowing the market preference for long spiral housing, some makers started winding a ballistic, anti-buckle layer around the steel core (under the cover) to prevent failure. They're also gambling that other factors, liner wear, friction, cosmetics or simply boredom with the bike will have the owner replace the housing before the structure is compromised.

So long spiral housing is OK for brakes, but only if it's made for brakes, and used with non-conical ferules. Use of long spiral index housing made for gear cables is still unsafe.
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Old 04-16-14, 03:26 PM   #7
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Originally Posted by FBinNY View Post
Long spiral (low helix) or so-called compressionless housing was developed for it's superior ability to transmit position rather than tension. It as long considered unsuitable for brakes for two reasons

1- at high compression load the ends will try to extrude through the conical bottom of brake fittings and ferrules. This is correctable with a proper ferule with a reverse conical bottom which forces the strands toward the wall rather than the hole.

2- and the more important reason, is the mode of failure. A high helix, aka spring coil has the coils sit on each other constrained by the wire passing through the middle. In the event of failure a single coil may (very rarely) over another, but in general the cable depends only on the steel for it's compression strength.

Compare with the long spiral where the strands run lengthwise. At high compression the strands want to buckle outward and are constrained only by the plastic cover. If the cover is cut, UV compromised, or otherwise damaged the cable will buckle under load bursting and failing completely. Given how brakes work, one can rest assured that this kind of catastrophic failure will happen at the worst possible moment, when brakes are most needed.

This is why long spiral housing was often marked "not for brakes"

BUT

Knowing the market preference for long spiral housing, some makers started winding a ballistic, anti-buckle layer around the steel core (under the cover) to prevent failure. They're also gambling that other factors, liner wear, friction, cosmetics or simply boredom with the bike will have the owner replace the housing before the structure is compromised.

So long spiral housing is OK for brakes, but only if it's made for brakes, and used with non-conical ferules. Use of long spiral index housing made for gear cables is still unsafe.
Got it.
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Old 04-16-14, 05:23 PM   #8
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Since it was brought up

If the OP is using long spiral (index style) cable, a likely cause of his problem is using no, or the wrong type of ferule. The conical bottom of the fitting or ferule, will cause the ends to pinch together binding the cable.
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Old 04-17-14, 04:49 AM   #9
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It occurs to me that gear housing is probably unnecessary for front shifting; brake housing should be accurate enough for any front shifting system (especially given the absence of a moving loop), and would likely deliver a better feel.

Shift housing feels kind of dead when you compress it (compressionless is such a misnomer), compared to brake housing's springiness... brake housing has less hysteresis, so it may actually be more accurate in this application, at least until you turn the bars past 30° or whatever.

You could probably do away with shift housing entirely on a SRAM bike; the longer cable pull would tend to drown out noise from the housing, and what there is of a RD loop doesn't move.

I'll try to perform the experiment one of these days.
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Old 04-17-14, 06:38 AM   #10
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Wow, thanks for all these responses, I'll have a good look at the bike later.
I'm also suspicious I might have misdiagnosed the problem, it could be the brake levers which are causing friction/making noise. So an oiling for them to rule that out.
Cheers again!
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