Punctures are a fact of life — here's how to fix one
Even if you’ve gone tubeless you should still know how to repair a puncture in an inner tube. You will need to repair a puncture at some point in your life.
How to repair a puncture
You will need a puncture repair kit, a tyre lever or two, and a pump of some sort.
Remove the valve dust cap.
Undo the valve lock ring (presta valves only).
Let any residual air out of the valve so the tyre is as flat as possible.
Work your way around the tyre with your hands, manipulating both tyre beads away from the rim as much as possible.
Remove the punctured inner tube from the wheel.
Re-inflate the inner tube and try to locate where the puncture is.
If you can’t easily locate the leak (ie. if it’s a small/slow leak) then put the tube up to your ear and gently rotate the tube past your lughole until you hear the leak.
If you still can’t locate the leak then you’ll need to fill a washing up bowl or bucket with water and pass the tube through the water and keep an eye out for telltale stream of bubbles.
Once you’ve found the hole it’s a good idea to inspect the inside of the tyre at the same point as where the leak was. This way you can remove any thorns/bits that are still in there and/or check for cuts in the tyre.
Mark the location of the puncture on the inner tube with a pen/crayon/chalk.
If you’ve had a rapid deflation after whacking a rock or doing a rough landing then chances are you’ll actually have two punctures in your inner tube, side by side AKA a pinch flat or snakebite. If these cuts are bigger than a few mm then it’s probably not worth trying to repair them. The patches won’t hold. New inner tube time unfortunately.
Patching time. Glueless patches are quick but often don’t work reliably and will leave you with a slow leak. Proper puncture repair kit patches are the best but they do take longer to execute.
Dry the area around where the puncture is. Roughen up the area on and around the puncture with a bit of sandpaper.
Put a bigger-than-the-patch sized amount of glue on and around the puncture. DO NOT put the patch on straight away. The glue needs a minute or two to react with the inner tube rubber. Hold your horses and wait until the glue goes tacky.
Put the patch on. Hold it in place with your thumbs for a few seconds.
Then (carefully!) remove the backing plastic/paper from the patch.
Ideally you should put some talcum powder on the repaired area to cover up the excess glue. But it’s not always possible. If you can improvise with some dust or fluff (delve into your pockets or Camelbak recesses!) to cover up the gluey bits then that’s good too.
Put the tube back in wheel.
Re-install the both tyre beads. Ideally with your hands. Watch the video to see our mechanic’s method of loosening up tight beads with just your hands.
But if the tyre is simply too tight then you’ll have to use a tyre lever. The danger here is that you stab the inner tube with the end of the tyre lever and puncture the whole thing all over again!
So if using a tyre lever do your utmost to make sure the inner tube is away from the tyre bead as much as possible. Try not to stick too much tyre lever under the tyre bead too. Take it slow and steady.
Pump your tyre back up before putting it back in your bike (in case the repair hasn’t worked and you have to try again or swap it out for a complete new inner tube).
Why learn how to repair?
It’s the responsible thing to be as self-sufficient as possible, so make sure you’re armed with the right kit. You should carry at least one tube, a decent pump, a puncture repair kit, some tyre levers and a tyre boot on every ride.
When you’ve punctured on your own, no spare tubes left, in the arse end of nowhere, just as the weather has turned, you want to be able to get rolling again pronto.
If you race, then being able to fix a puncture quickly is essential, and could mean the difference between a podium position and a DNF.
Being properly equipped also means that you won’t irk your buddies by ‘borrowing’ gear from them next time you flat.
If you’re fixing a flat at home then make sure you have a track pump to make things easier, and check your pressures before every ride, because riding with a properly inflated tyre will help prevent that sinking feeling as well as boosting your performance.
If you have to fix a flat on the trail, then please remember to dispose of your rubbish responsibly — slinging your old tube in the bushes is a pretty poor show and gives us all a bad name.