Compressionless brake housings for cable discs.

[PH]

So was I, but it fits a treat.
I don't understand Brucey's point of view. Never ever had a gear outer "collapse" or heard of it before.

Well you've never used one as a brake outer before either
It's not Brucey's point of view, it's every bike mechanic and cable manufacturers, I could find you a hundred quotes in ten min that it's a bad idea, here's the first

Please Note: Due to their construction, brake housing should always be used with brakes and shifter housing should always be used with shifters. Shifter housing could fail if used on a brake (not good when you want to stop), brake housing could make that shifter feel a little dead.

https://bicycles.stackexchange.com/ques ... eur-cables

Yes it improves the brakes, that's why you can get compressionless brake outers

[Mick F]

Why does it fail?

It looks damned strong and solid to me, and probably more expensive to produce, so that's why they use brake cable for brakes as they're cheap.
Brake cable wouldn't work with indexed gears, so they spend more to make them compressionless.

No real experience of anything other than Campag Ergo cables and the Shimano STI stuff on my Moulton has long gone. Anything before on my bikes were DT shifters, so the only bit of gear outer was the few inches back by the rear mech.

[PH]

How about Sheldon? Do you think you know better than them all?

Warning: Since compressionless housing relies on plastic to hold it together, it is not as strong as conventional spiral housing, and should never be used for brakes! The loads applied to brake cables can easily cause compressionless housing to rupture and burst, causing a complete and sudden loss of brake function.

https://www.sheldonbrown.com/cables.html

[Mick F]

I've disagreed with the late SB on a few subjects, and one of them was braking.
I've disagreed with Yannick(?) on a couple of things too.

I'm going to try with this Ergo gear cable on my Moulton despite warnings.
I'll let you and everyone else know if I have issues.
May have to wait until Monday before I go out for a ride on it.

I have a short 3ins cut-off length of Ergo gear outer and I tried cutting off the plastic outer with my sharp penknife to inspect the innards and see how it's made and constructed.
I couldn't do it, but I will continue to try.

Seems very very tough to me, and well made as well and can't see how it could rupture. Maybe over a whole 4ft length from the 'bars to the rear brake maybe, but I'm talking of only 14ins.

[Mick F]

Managed it.

17 stainless steel strands of 0.5mm each arranged in a lazy twist, and surrounded by a thick and hard plastic outer.
Internally, there's a tough nylon inner sleeve.

Overall outside diameter is 4.4mm
Inner sleeve measures 2.4mm OD

[Brucey]

gear cable housing quite often fails under mere gear cable loads. Under full braking loads it is no good at all. If it were any good for brakes they would sell it as brake housing; as it is they go to the trouble of producing proper compressionless brake housing that is strong enough and is reliable. It has extra reinforcements in it so that it isn't going to come apart at the seams. Why you wouldn't want to use some of that is quite beyond me.....

cheers

[Cunobelin]

I have simply used gear cable outers with no issues whatsoever ................. Been my practice since the early 90's and never had a failure yet

This idea has never occurred to me, but it sounds a brilliant idea especially for the longer rear brake cables.

Not on Mercian as a "normal" road bike coz that's fine, but Moulton has a rather convoluted rear outer at the rear end of the cable run.
I've fiddled for ages with it trying to route it better, but a gear outer could very well improve matters as the rear brake feels spongey and vague as it is.

It's worth an experiment.

Long cables..... you call that "long"?

Try fitting a cable on something like a Linear!



Even then the front brake was spongy


I agree with the Moulton though, the same was true on my Pashley APB. I cheated....

There is a split in the cable where the cables join allowing the frame to split.

I put a Nokon cable in from that point.Allows for some very tight and convoluted turns that would cause problems for a "normal" cable

[Cunobelin]

gear cable housing quite often fails under mere gear cable loads. Under full braking loads it is no good at all. If it were any good for brakes they would sell it as brake housing; as it is they go to the trouble of producing proper compressionless brake housing that is strong enough and is reliable. It has extra reinforcements in it so that it isn't going to come apart at the seams. Why you wouldn't want to use some of that is quite beyond me.....

cheers

Because it is stiffer, improves braking... and simply works?

[alexnharvey]

It works great... right up until it doesn't, failing catastrophically.

Compare with a spiral brake cable and presumably also a compressionless brake outer which typically fails progressively.
Even if the plastic cracks you still have a working brake system.

What mode of failure would you prefer in your brakes?

I also think you have missed Brucey's point. What is the advantage over compressionless brake outer, which is also stiff, also improves braking, also works and crucially does not have an inherent flaw!

[Cunobelin]

:roll: Total madness Mick.

Does't take much looking to find some pictures of failed gear outers. I wouldn't like to be braking with them



https://www.aquabluesport.com/blog/buye ... ables.html

Well after over 25 years, and thousands of miles.......I have yet see this.

[Brucey]

Because it is stiffer, improves braking... and simply works?

on your trike you may (for various reasons) have cable loads that are regularly about 1/3 or 1/4 of that seen on a road bike.

When the cable manufacturers clearly stipulate that you should not use their gear housing for brakes, they do so for a good reason.

I don't understand for one second why you don't use proper compressionless brake housing; it is made for the job (it is much stiffer than gear housing) and it is not expensive.

cheers

[Mick F]

If compressionless brake housing is so good and cheap, why isn't it ubiquitous?

I still intend to use the Campag Ergo 14ins of gear cable for the rear section on Moulton as it feels brilliant.
Nothing has changed my opinion on this.

[Brucey]

If compressionless brake housing is so good and cheap, why isn't it ubiquitous?

it is slightly stiffer (in bending) than spiral wound brake housing and it is slightly more expensive to make. Most brakes don't benefit a very great deal from having it, either.

FWIW the main reasons (pashley built) moulton cable runs go bad is

1) they are fantastically stupidly designed, with extra bends for no good reason and arranged so that water runs into the housing at the lower cable stops and collects in a low spot (a design feature that was eliminated from most bikes about forty years ago) and
2) the cable stops on the frame are variously badly shaped and badly aligned on the frame. I spent half a day trying to fit proper ferrules to a moulton a while back and no two cable stops would fit the exact same ferrule in the same way; they were all over the place.

The TSR rear cable run is a lot more sensible if it is connected to a V brake than a DP caliper. For the latter I'd suggest a couple of these



and some decent normal housing between them, if the bends are troublesome.

cheers

[Mick F]

Not had any rain in any of the housings.
Not had a problem with the Araldite to fit the extra cable boss I fitted for the Sturmey Archer cable either.
Only issue is the spongey rear brake, and that seems to have been eliminated by the Ergo gear cable.
I will use the Ergo cable ......... and continue to use the Araldite ............ despite your warnings and advice.

[amediasatex]

I had this very discussion with my boss as a Saturday boy at the age of 15 in the local bike shop. I thought I had ‘solved’ a crappy brake issue by using gear outer and gleefully showed him my fix.

He proceeded to educate me by grabbing the brake lever with all four fingers and hauling on it with all his might, which very promptly split right in front of me in the workshop, not my proudest moment and suffice to say I then somewhat sheepishly fitted some brake outer.

I’d ridden it round the car park with no ill effect, but my few test stops clearly hadn’t put much load through it. In the following couple of decades working on bikes I saw plenty more cases of gear outer having split just from gear cable loads and fatigue or a little damage to the outer then causing further issues, and also a few cases of people trying the same thing and also suffering split cables, sometimes almost immediately, other times after a few months, but either way it’s just not worth the bother, either use spiral brake outer or proper compressionless outer.

Even if it works fine to begin with you only need to not notice one tiny crack or split in the outer casing and then on the next hard stop it can fail, and it’s not a graceful fail, it’s a lever back to the bars suddenly with no brake kind of fail. Even the best of us who check things regularly don’t check every inch of our outer before every ride...

Even if you have been lucky, or intend to be lucky , please refrain from suggesting that other people take the risk, if you want to then fine, but it’s just not OK to suggest that others should.