Fixing a Puncture

If the bike has been sitting for a long time, it may pay to pump the tyre up and see if it has a puncture. It may have just gone down over time.

If you are out riding, you will need a spare tube or puncture kit, tyre levers and spanners if your bike does not have quick release levers.

If you are going to attempt to repair the puncture, you will also need some way of finding the leak. This is usually done with water.

If you do not have much water it can be done by using a sandwich bag with a small amount of water in it and rotating the tube through it bit by bit while looking for air bubbles.

This article is all about fixing punctures and has pictures that you can follow. There are many different types of tubes and tyres so we cover the common type in this article. Your tyres and tubes may be different than the type shown here.

Here's hoping that you know how to repair the tube, but never get a puncture!

What You Need

To repair a punctured tube, you will need tyre levers, a pump that fits the valves on your tubes, a puncture repair kit which contains sandpaper, glue, chalk and patches and/or a spare tube. Unless you have quick release skewers on your wheels, you will also need some spanners.

The different valve types are Shrader and Presta, and are the two most common types of valves. You may encounter others, but they are rare. Make sure you carry a pump that fits your valve type and is capable of inflating the tyre to it's recommended pressure.

Removing The Tube

It is a lot easier to fix a punctured tube after removing the wheel from the bike. It is possible to repair a punctured tube whilst the wheel is on the bike, but we will not cover that here.

To remove the wheel, you will need to disconnect your brakes so that the brake pads are clear of your tyre. You then need to undo the wheel nuts or quick release skewer. If it's the back wheel, you will also need to move the wheel out carefully while keeping the chain clear.

You will then need to remove the valve cap and fully deflate the tube if it is not already deflated. You can do this by pressing the valve pin down. On Presta valves you will need to unscrew the nut on the pin first. For Presta valves and the old style Shrader valves, you will also need to remove the locknut at the base of the valve which is against the rim.

Levering tyre off to repair a puncture.

Starting opposite the valve you will need to insert the smooth end of a tyre lever under the bead of the tyre.

You then need to lever the bead up and then hold it in place by inserting the other end of the tyre lever over a spoke.

You then need to move a little further along and do it again. At this stage, you are at the level as shown in the photograph.

You can now use a third tyre lever or using the second lever, carefully move it around the tyre and lever the bead up and over the edge of the rim. Do this until you have done the entire tyre.

At this stage you can press the tube's valve through the rim and remove the tube by pulling it out around the edge of the lifted tyre bead. If you are not going to repair the puncture until you get home, you can jump straight to Installing the Tube.

Repairing The Tube

We now need to locate the puncture hole. This can sometimes be done by examining the tube visually, or if you are in a quiet spot, by pumping the tube up and holding it to your ear and listening for a hiss. It usually requires water to locate the hole, so a water source and a bucket or other container is required. A small sandwich bag with a small amount of water in it is also usable if you are on the road and have a shortage of water.

Mark it with chalk.

Pump the tube up and then insert it into water. If you can't submerse the entire tube, you will need to rotate the tube around until you see air bubbles. When you see the air bubbles, this is the source of the puncture. Mark it with the chalk.

One Tip here, is to check the entire tube to look for other punctures. Sometimes there are multiple holes in the tube.

Once you have done this, you will need to clean around the puncture by roughing it up with the sandpaper or metal rasp that is in your puncture kit.

Next select the appropriate sized patch and apply an even coating of glue to the area around the puncture slightly larger than the patch. Allow the glue to dry for a few minutes, then remove the foil from the patch and press the patch firmly over the puncture. If you have something heavy to put on it, use it, otherwise you will need to apply pressure for a couple of minutes.

Dried Patch

While you are waiting for the glue to dry, check that the spoke tape on your rim is in place covering the spoke heads (nipples)

Then run your fingers carefully around the inside of the tyre looking for anything sharp that is protruding into the tyre.

Once the patch is dry, (there should be no loose edges on the patch) you are ready to install the tube back into the tyre.

The picture to the left shows a dried patch in place. Patches come in many sizes and shapes. Always select the smallest one that will safely cover the puncture holes and have plenty of area for the glue to hold.

Installing Tube

You are now ready to reinstall the tube into the tyre. Make sure that one side of the tyre is on the rim. Then put a little bit of air into the tube to give it a basic shape. Then insert the tube with the valve inside the tyre and feed the valve through the hole in the rim.

Holding the valve, insert the rest of the tube back into the tyre. Once this is done, hold the valve and push it down as though you were going to push it out again. Holding the valve firmly with one hand, use your other hand to seat the tyre back onto the rim in the area on both sides of the valve.

You can now let go of the valve and working in both directions away from the valve slowly work the tyre back onto the rim. Be careful that you don't pinch the tube. As you get closer to having the entire tyre back onto the rim, it will get harder. Make sure that the valve is straight before doing the final part of the tyre.

You may need to let some air out of the tube, but most tyres will go back on by hand. In some cases you will need to use tyre levers. Take extreme care that you do not pinch the tube with the tyre levers as this is the most common cause of punctures when reinstalling the tube.

Carefully check the edges (bead) of the tyre for any signs of a pinched tube around the rim. Replace any lock nuts removed on the valve and pump up the tyre and replace the valve cap. You can then reinstall the wheel. If it's the rear wheel, you will have to get the chain back onto the gear cluster and this is where you get your hands dirty.

Don't forget to reattach the brakes and tighten the wheel nuts or quick release skewers. If all goes well your tyre should stay up. There will be times when you will have to swear and remove the tube again to fix another puncture, either because you missed a puncture hole, or because you pinched the tube when reinstalling it. Sometimes you may have also missed something sharp embedded in the tyre.

I always try to install my tubes so that the valve is level with some writing on the side of the tyre. When I find the puncture hole I am able to locate the spot on the tyre and check for any embedded sharp objects.

If the puncture hole is on the inside of the tube, then the tube was punctured by the spoke heads. Make sure that you carefully check that the rim tape is still in place and in good condition.