Without a spare cable, certain things (like brake failure) tend to be terminal in a riding sense.

But gear cables aren’t as bad. Should the front cable go, you’re simply committed to the small ring for the rest of the day, which is far from a disaster, especially in terms of riding home. But if the rear snaps (or the rear shifter stops working) then it’s a more intricate fix.

Video: How to fit a road bike gear cable

Should the shifter fail, rather than the cable, start off by pushing the rear derailleur into the gear you want while turning the pedals. Then unscrew the cable stop on the derailleur body itself, pull the cable through until it’s tight (not all the way through, obviously), and re-tighten the bolt. This should hold the bike in your chosen gear and you can use the barrel adjuster to make sure that the chain sits perfectly on your chosen rear cog.

Maintenance guide: How to replace a road bike brake cable

If the cable snaps, tie a knot in the cable and thread the rest of the cable back through the derailleur. The knot will act as something for the derailleur to pull against, and you can push the derailleur into the gear you want, and fasten the cable through the stop as described above, which will hold it in the one gear. You can even use the barrel adjuster to fine tune, too. Wind up the excess cable tightly so that it won’t flap about and get caught in the chain or wheel.

Should it be a brake cable that snaps – and provided you aren’t off on a free ride in an ambulance – then it’s time to ride home very carefully.