Eric F 

If broken cables is a serious problem (I'm betting it's a maintenance/use issue), and breaking one will leave you totally stranded, the best bet is to carry an extra brake cable and an extra derailleur cable with you. Learn how to install it and adjust it in the field. In reality, unless you're riding in extreme conditions, in remote parts of the world, it's most likely that you can ride to a place of safety/repair without the use of one brake and/or one derailleur.

FBinNY 

FWIW electrical connectors are not suited to load bearing applications.

They're only capable of supporting the weight of the wires, plus a reserve for vibration. ANY meaningful tension will pull the wire free.

There are load capable connectors. They usually have visible means of distorting the wire, ie. a raised bump with matching hollow, to make a bend that resists slipping.
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If you're going to carry something for emergencies, carry a spare cable. Or buy a staight pull spoke and cut a 2" segment. In a pinch this can be used in the RD to select a single middle gear, and trim with the barrel. Now you have a 2s to get home with. In a pinch, you can reset the spoke to select a lower gear gor a tough climb.

choddo

Could this fraying be related to the apparent infrequent maintenance evident in certain photos?

I mean, I’ve had a couple of cables go from fraying - but only inside the shifter (and I suspect that was partly down to twisting them during installation while the nugget on the end was trapped) But never had a brake cable go that way. Or any way come to think of it.

I totally relate to the economic challenges though. Not right now thankfully but back in the day… basically every job on my bike as a kid had better be fixable with an adjustable wrench, a drill or a hammer. That was my entire toolkit.

mpetry912 

you're talking about a hydraulic crimping tool with forged dies that compresses a steel sleeve, and you're right, those are very strong. Like aircraft control cables.

but the OP was referring to those color coded wire crimp connectors that you buy off the rack at a hardware store and those are definitely not safe for use as brake cables. A cable "spliced" that way will pull apart at the worst. Possible. Time.

Don't do this, people.

/markp

grumpus

"Tin plated brass" so you'll not get a lot of clamping force before it threatens to strip - copper or aluminium cables deform which helps grip when they're clamped, steel not so much. Also you'd need to fold the cables several times or find some other way to fill that big gap.

grumpus

Things you can do to save money on cables: buy in bulk, you can get ten cables for under a tenner, which is way cheaper than ordering individual cables and you'll have a spare as soon as you need it. Buy universal cables, the ones with a different nipple on each end - if you're lucky you can get two front cables from one universal, but you need both a road bike and MTB to make use of them. Re-use a rear cable on the front when it's all chewed up by the clamp but the rest of the cable is fine. Make/repair your own - not really relevant here, but if you have the equipment and inclination you can make nipples from steel or brass and solder on - repair a cable the nipple broke off, or use an offcut to make a straddle wire.
Grease: if you grease a cable when you fit it, it will work better for longer.
Fraying: fit a crimp or solder the end to stop it fraying, then you stand a chance of refitting it after cleaning and greasing. Don't overtighten pinch bolts to the point that they cut cable strands - if you get cut strands check for sharp edges and soften them with a small file.
Casing length: the casing will be long enough that it doesn't kink at any point in its movement, and short enough that it doesn't introduce unnecessary slack into the system (or just wave in the air and look stupid/get caught on something). Curves should be smooth, S-bends minimal (if the cable bends one way then the other, consider if one of the bends can be reduced or removed by shortening the housing). Good routing will allow cables to work better for longer.