Small portable cable cutters for touring

General cycling advice ( NOT technical ! )
Brucey
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Re: Small portable cable cutters for touring

Post by Brucey »

mnichols wrote:BTW, my experience is similar to horizon. I replace my cables before each tour, but have still had occasions when they have broken, which is why I carry spares.

I am replacing my cables several times per year, but they don't seem to last. Mostly they fray at the mech, but I have had a couple fray and break inside the shifter, and some with the odd strand coming lose. My local bike shop say that I most be heavy on them, but not sure how I am doing that - surely a shift is a shift?


I agree that gear cables (and sometimes brake cables) are bound to break sooner or later. I think that some cables are substandard (and there have been recalls on cables, even shimano ones).

However if you read engineering texts which describe how to design machines using wire ropes (cables) so that the wire ropes won't fatigue in use, you will quickly notice that nearly every bicycle product on the market takes the most appalling liberties with the known design rules.

This gives some information on how rope design affects fatigue life

http://pythonrope.com/wireropes/wr_techinfo_6.shtml

note that bicycle cables have fewer strands again than these, arranged in helical winds, not bundles (strands). So they (relatively speaking) fatigue even faster.

You can see some more data here;

http://www.wwwrope.com/product_pdfs/EL_TB_09.pdf

Realistically a good quality gear cable might do ~100000 shifts or so on a typical shifter drum. This is borne out in practice; a friend of mine (who changes gear very often) has calculated that his cables last no more than 130000 shifts before they fail.

In the rear mech pinch bolt the fatigue is often worse; shifts (between the smaller sprockets especially in shimano mechs, check out the cable angles) will bend the cable near the pinch bolt quite abruptly. Corrosive conditions, lack of lubrication, high force (shifting under load) will all add to the fatigue damage. Front mechs can suffer too in a similar way.

In any event sharp edges on pinch bolt clamps can damage cables during installation. Sometimes a little filing can put a useful radius on the clamp. If you solder the cable ends to try and stop the damage, it just moves the fatigue someplace else because the soldered cable doesn't bend so well, and where it does bend, it fatigues.

Very many 'V' (and especially cantilever brakes whose arms articulate more) have pinch bolts that force the cable to articulate in a tight bend under load. You couldn't expect to design anything similar to break cables any better than that.... :shock: and if they are fitted with 'M' straddle wires, V boots or similar, the damage can be hidden from view.

So I agree that there are very many components that are basically designed to break cables in short order. At one time you could mitigate this by buying 'braided' brake cables but these seem to be no longer available.

No one manufacturer gets it right all the time, either; Avid's disc calipers have reasonable radii on them but their cantis are just like everyone else's; mostly with sharp flexures in the cable next to the pinch bolt.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
mnichols
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Re: Small portable cable cutters for touring

Post by mnichols »

Thanks for the very comprehensive answer Brucey. Interesting stuff
stevemb
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Re: Small portable cable cutters for touring

Post by stevemb »

I've tried 3 multi tools to cut or trim a brake cable with mixed success. A Leatherman Charge TTi did what an earlier post warned of, namely it spread the wire and the pliers got stuck together. The same thing happened with a Victorinox Swiss Tool Spirit. These two are both medium to heavy duty multi tools - obviously not designed for this type of job as prevoisly warned. Ironically the only success was with the old version of a Leatherman Wave (no interchangeable bit) which sliced straight through with a clean cut. Why the Charge, which has heavier duty pliers failed is strange.

I would only use these as a last resort as they are not designed to tackle this type of cable - my cable cutter at home thats part of my tool kit sliced it clean with no effort at all so if possible next time I'll wait to I get home
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Cunobelin
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Re: Small portable cable cutters for touring

Post by Cunobelin »

andrew_s wrote:I also take a rear cable, and just coil the excess if I have to use it.
Trim it when you get home - the cable will snap off where it exits the clamp bolt if left indefinitely (DAHIKT).

If you rely on a cutter, test before use. Leatherman-style tools (which give a scissor cut) generally don't cut cleanly, leaving cable strands zig-zagging between the jammed blades.
The only light and effective cutter I've seen was a home-made one, using a hardened cylinder andd screw-driven plunger that cut a cable threaded through initially lined up holes.


I carry a range of zip ties of varying sizes in my touring kit

This happened to me once, and all I did was coil the excess and zip tie to the frame.

Then at next town asked the bike shop who cut and capped the cable when I bought the replacement spare
merseymouth
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Re: Small portable cable cutters for touring

Post by merseymouth »

Hi There, It seems to me that many people rely on modern combined Brake/Gear Levers? Fine & dandy for the racing types, but surely D/Tube Indexed Levers would be much better for the less hurried user? Using D/T levers means a much reduced frictional load on the cable, by dint of shorter length & less outer cable. I've yet to miss a change with such a set-up. Oh, and its far cheaper as well! A simple drop can mean massive bills with STi/Ergo stuff! Still using older friction only levers as well, old Campag Record set with a 6 speed block on my 1953 Higgins Ultralite Diff Trike. TTFN MM
PH
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Re: Small portable cable cutters for touring

Post by PH »

merseymouth wrote:Hi There, It seems to me that many people rely on modern combined Brake/Gear Levers? Fine & dandy for the racing types, but surely D/Tube Indexed Levers would be much better for the less hurried user? Using D/T levers means a much reduced frictional load on the cable, by dint of shorter length & less outer cable. I've yet to miss a change with such a set-up. Oh, and its far cheaper as well! A simple drop can mean massive bills with STi/Ergo stuff! Still using older friction only levers as well, old Campag Record set with a 6 speed block on my 1953 Higgins Ultralite Diff Trike. TTFN MM


An alternative to that is to use the levers of choice and carry a down tube lever with cable as a spare. It weighs next to nothing and can be swapped out in less time than it takes to fix a puncture. I've carried one in the eight years since a crash damaged Ergo caused some inconvenience in the middle of a hilly Audax, though in that time I've never needed it.
merseymouth
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Re: Small portable cable cutters for touring

Post by merseymouth »

Hi there, How does that work when the frame is made of oversized steel, or worse that plastic stuff? TTFN MM
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andrew_s
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Re: Small portable cable cutters for touring

Post by andrew_s »

PH wrote:An alternative to that is to use the levers of choice and carry a down tube lever with cable as a spare.

Many current frames (even most?) don't have any lever bosses to mount a D/T lever on, just a cable stop/adjuster on the side of the head tube. Carrying a lever mount as well as the lever starts to look less attractive.
PJ520
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Re: Small portable cable cutters for touring

Post by PJ520 »

I think one problem is that people overtighten cable clamps, the spec for the Avid SD-5 brake's cable clamp screw torque is 40 in lb i.e. 10 lb at the end of a 4 inch wrench. Many people insist on seeing the cable squashed flat when tightening cable clamps.
You only live once, which is enough if you do it right. - Mae West
gplhl
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Re: Small portable cable cutters for touring

Post by gplhl »

simonineaston wrote:If your cables are regularly checked and lubed, you won't need to fit one while on tour..."


Depends on the length of your tour! :-)

I have found your never far away from somewhere that has a good pair you can borrow, you can normally get by for a while with one broken cable. Cable cutters are heavy bits of kit to carry that you may not need or only infrequently. People think I am nuts because I carry a hollowtech removal tool and one whole pannier is my spares/workshop!.. (outside of Europe I may add).

Regards,

Gary
www.longbikeride.co.uk
ukdodger
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Re: Small portable cable cutters for touring

Post by ukdodger »

mnichols wrote:I like to have a little tool kit with me when I'm touring, and I have most things, but one thing that has eluded me is a pair of small cable cutters for cutting brake or gear cables. I have had various ones as part of multi-tool sets usually as part of the pliers, but none of these have been tough enough to cut a cable

I know that the chances of me needing them are small, but I tour frequently and often with other people so I carry a spare brake and gear cable just in case, and if I could find a small light tool or one as part of a multi-tool that may replace another item it may be worth keeping with me.

Google and Amazon do show results, but my experience of these are they aren't tough enough for brake and gear cables, so I am looking for personal recommendations

Thanks in advance


Just wondering if you ever had any success finding lightweight cutters. I had the nipple come off of a Rohloff cable on a tour which meant replacing the whole thing (lucky for me I was near a bike shop who did the job). But the problem with changing Rohloff cables is the connection at the hub end. If the cable end isnt pristine tidy it wont go in the hole provided. So ordinary cutters dont make a neat enough cut. Most cable cutters are heavy and I'm loathe to add to the weight of tools I carry anyway.
LollyKat
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Re: Small portable cable cutters for touring

Post by LollyKat »

Some people recommend putting some superglue on the cable before cutting - apparently it makes for a tidier cut. I have no idea how well this would work with cheap cutters on a Rohloff cable. I always take a small tube of superglue with me for general emergencies. I haven't used it on the bike but it did a beautiful job of sticking the sole back on to one of my cycling shoes.
ukdodger
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Re: Small portable cable cutters for touring

Post by ukdodger »

LollyKat wrote:Some people recommend putting some superglue on the cable before cutting - apparently it makes for a tidier cut. I have no idea how well this would work with cheap cutters on a Rohloff cable. I always take a small tube of superglue with me for general emergencies. I haven't used it on the bike but it did a beautiful job of sticking the sole back on to one of my cycling shoes.


Lol. Good idea. I'll test try that.
mnichols
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Re: Small portable cable cutters for touring

Post by mnichols »

ukdodger wrote:
Just wondering if you ever had any success finding lightweight cutters. I had the nipple come off of a Rohloff cable on a tour which meant replacing the whole thing (lucky for me I was near a bike shop who did the job). But the problem with changing Rohloff cables is the connection at the hub end. If the cable end isnt pristine tidy it wont go in the hole provided. So ordinary cutters dont make a neat enough cut. Most cable cutters are heavy and I'm loathe to add to the weight of tools I carry anyway.


No, I just change all the cables before each tour and hope for the best
ukdodger
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Re: Small portable cable cutters for touring

Post by ukdodger »

mnichols wrote:
ukdodger wrote:
Just wondering if you ever had any success finding lightweight cutters. I had the nipple come off of a Rohloff cable on a tour which meant replacing the whole thing (lucky for me I was near a bike shop who did the job). But the problem with changing Rohloff cables is the connection at the hub end. If the cable end isnt pristine tidy it wont go in the hole provided. So ordinary cutters dont make a neat enough cut. Most cable cutters are heavy and I'm loathe to add to the weight of tools I carry anyway.


No, I just change all the cables before each tour and hope for the best


Thanks. That's what I'm about to do too.
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