Cams - Field repairs image

Cams - Field repairs

August 6, 2017

The following is an extract from my up and coming book Higher Education, the most exhaustive big wall climbing book yet written. 

On hard, intensive walls, where cams are being placed and removed hundreds of times, as well as being twisted, bent and abused, trigger wires will break. Such problems when they appear on the ground are annoying, something to fix when you’ve got time, but on a wall, the loss of a single unit can mean the loss of a climb. Scale that up to a long trip far from home, and you could have a problem that unless remedied could ruin a trip of a lifetime.  Here are some ideas on how to stop your wires from breaking, and how to deal with them when they do.

#1 Look at your cams!

This is a big one, as the trigger wires that come with camming units should last the lifetime of the cams, and I have cams that are worn to a nub and yet still have the cables they came with.  How wires get broken is often due to poor transportation, all your rack just dumped into your pack after a climb, or onto the floor. Cables and wires have a tendency to get hung up, snagged and tangled on everything else, and yanking your rack apart just wrecks them. Any kink added to a stiff wire is a future break. Instead, you should get into the habit of bunching your cams together and in line, and ideally store them in a stuff sack when not being used. Large cams such as size 4,5 and 6 need more care, and I would try and use a stick to keep the lobes retracted when not being used, as they tend to snag on everything.

Keep them clean and lubricated

Dirty cams resist the trigger and so require more pressure on the trigger.  Dirt, salt and Keep them clean by washing every now hot water and soap, scrubbing them clean with a toothbrush. Lubricate the cams with a graphite lubricant that will not attract dirt (bike shop), or with good old WD40, which does attract dirt, but has seen climbers proud for several decades.

Don’t set off with dodgy wires

If your Camalot 3’s trigger is hanging by a thread, with just a single strand of wire the only thing between working and not working, then sort it out before you leave the ground!

Trigger kits

Most brands sell trigger kits that can be used to replace damaged units, and it’s always best to go with what the manufacturer recommends.  The downside of this approach is that you never have such kits when you need them, and the moment the ones you’ve ordered arrive you’ll find a broken cam you missed.  Having a lot of cams, I tend to just repair them all myself at home.

Wall repairs

Being able to fix your cams on the fly is vital on any big wall, doubly so if you’re on an expedition, and by carrying a few specialist items in your tool kit, you can quickly make running repairs.

Alien and Totem Basic with wall repairs, with 0.75mm wire on right and 0.48mm guitar string on left.
Cam repair kit

A basic cam repair kit can vary from nothing but a roll of dental floss to a kit comprising of multiple thicknesses of wire, swages and multi-tool, the emergency repair versus a repair that lasts for years.


No climber will have the correct tools for a professional job, namely wire cutters and a swaging tool, and instead, you will need to improvise. The best tool for this is a multi-tool, and you will need this to cut away old cables, pull cables out, then cut the new wire and crimp your swages. Cutting multi-strand wires cleanly can be difficult without professional clips, leaving stray wires that affect insertion or make it impossible, and for this reason, I’m a fan of single-strand wire, monofilament or fluorocarbon as it can be cut easily.  One method that can work for multifilament wire is to use the tip of a blade or sharp piton and hammer it, creating a guillotine.

Cables - how thick?

The diameter of the wire used on camming units vary, but as a rule of thumb the standard hole drilled into cam lobes on small to medium cams tends to be around 1.3mm, so avoid anything more than 1.3mm (clean out holes with the stiff broken cable to make insertion of new cable easier).  Holes on micro cams such as the blue alien or C3’s are smaller still, around 0.8mm, working best with 0.75mm cable, while the smallest units need even smaller, with 0.5mm wire required.

How strong?

The factory-built cables are designed for decades of hard use and are also designed to look and feel like a cam trigger. You’re on the run repairs do not need to be up to the same standard.  I expect most companies could switch to a monofilament or fluorocarbon cable to in-place all the swages and wire, cheaper and easier to replace, but don’t, because climbers are resistant to change (just look at the resistance to the excellent Metolius Master Cams kevlar trigger cables).  Again, you don’t face the same commercial worries and can make use of whatever you want.  When making repairs it’s good to have a good selection of materials to choose from, and a few mini z-lock bags containing a metre of rolled-up wire weighs nothing.

Monel Seizing Wire

This is 0.8 mm marine wire that comes in a 10m spool and having a few metres in your repair kit always pays dividends. The wire is very stiff but flexible and does not seem to weaken after being bent at right angles.

#2 1.2 mm Brass picture frame wire

This is a fantastic emergency repair wire, being thin enough for the smallest cams, stiff but easily twisted or bent.  This wire works best on micro cams and does not require any other components or swages.  I’ve also used this to repair broken triggers.

Paper clips

Always worth having in your repair kit, these make good stiff wire replacement for medium to large cams, ranging in diameter between 0.7mm and 1mm, and can be used alone or swaged into a cable.

1.2mm monofilament strimmer line

This is one of my favourites as it’s the easiest to do on the fly, and needs no special tools to be used on medium to large cams (Camalot 4’s and 5’s, which tend to suffer trigger damage often). Cut the line at an angle to make it easier to insert and melt the ends of the ball up and act as stoppers. 

0.48mm steel guitar string

This works very much like picture frame wire, being very stiff and high strength, but also available in diameters below 0.5mm.  I find this is the best way to repair tiny camming units such as black Aliens.

3/64 (1.19mm) 7x19 Aircraft grade stainless wire

This is the best wire for standard cams 7x19 construction far more flexible than 7x7 as it’s much more flexible and high strength. Make sure your swages match the wire.

0.75mm 7x19 stainless wire

Very thin but still strong, this is ideal for micro cams.


Much higher strength than you’d imagine, and suitable for temporary cam repair.

Fishing line

A heavy-duty fishing line is easy to tie and cheap and can be used for fishing too!  Heavy-duty deep sea fishing line with high breaking strains is surprisingly strong, with fluorocarbon line being even stronger than monofilament line. This can also double up for other repairs, even sewing.

Whipping twine

Designed for yachting ropes, this high strength waxed cotton is an excellent all-round cord for repair kits, suitable for heavy-duty sewing too.


Swages are soft alloy or copper sleeves into which you insert two wires and then crimp together. If crimping with a multi-tool use the wire cutter to carefully crease the sleeve without actually cutting into it. If you don’t have a multi-tool, then use a hammer/rock to hit a blunt-edged piton to compress the sleeve. Alloy swages are easier to crimp than copper, and make sure you match the correct swage to the correct cable. Industrial wire or fishing tackle sites are the best places to buy swages, as well as swaging tools.

Where to buy your wire and swages?

There are lots of places to buy wire from, but I tend to use in the UK, but you can also get bits from fishing shops (wire, swages and crimpers) and ships chandlers.

You can pre order Higher Education here

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