The most common job for any bike shop, but something every cyclist and utility bicycle user should know how to do
For seasoned cyclists, it is the easiest thing to remedy: a flat tyre can be quickly solved with a patch or a new tube. But for those new to road cycling, or giving cycle commuting a go, it’s not always obvious where to start when you need to fix a puncture. Below is our step-by-step guide to get you riding again when your tyres go flat.
Before we look at how to repair a puncture, first a word about tyres. Choice of tyres is almost as important as the wheels or frame. First of all your tyres need to be the correct size to fit your wheels. They need to be pumped up to the pressure recommended on the sidewall of the tyre — too much pressure will blow the tyre off the rim and too low a pressure will allow pinch punctures and tyre wall damage. It’s also best if they are the right tread for the surface that you are riding on, the time of year and what riding you’ll be doing.
>>> See our buyers’ guide to road bike tyres
Tyres that are smooth because they are worn out are useless and dangerous. Tyres that have a series of tiny cracks in the sidewalls or between the tread blocks need replacing too.
From time to time, a tyre may have some internal damage which results in a bulge somewhere around its circumference; this is another occasion when the only remedy is a new tyre.
Finally, the inner tube: make sure any replacement inner tube is the right size for the tyre, and you have the right type of valve to fit through the hole in the wheel rim. See below for valve types.
Step 1
Open the quick release lever on caliper brakes, or disconnect the brake wire if you have cantilever or V-brakes. If you have disc brakes you don’t have to do anything. If it is a rear wheel puncture, adjust the gears so that the chain is on the smallest chainring on the crankset and the smallest cog on the rear cassette. This makes rear wheel removal easier. Undo the quick release lever or the wheel nuts and take the wheel out.
Step 2
Take off the valve cap and unscrew the valve retaining nut if there is one. Remove the cause of the puncture if you can spot it and make a mental note of where it is in relation to the valve.
Step 3
Making sure that the tyre is fully deflated, put two tyre levers between the tyre and the wheel rim directly opposite the valve. Lift a tyre lever so that the tyre comes off the wheel rim, then do the same with the next lever. If you have three levers, hook the first two under the spokes and remove some more of the tyre with the third lever. By now the tyre should be loose enough to simply run a tyre lever around the wheel rim to remove the rest of the tyre. With experience, you may only need one tyre lever.
Step 4
Pull out the inner tube and take the tyre off the wheel completely.
Step 5a: using a patch
If the puncture is not obvious, pump up the inner tube. Once inflated, it is usually easy to hear the air escaping. If not, run the inner tube past your lips to sense the escaping air. Once located, roughen the area around the hole thoroughly with the emery paper in your puncture outfit. Apply enough glue to cover an area a little bigger than the repair patch that you’ll use. Do this a couple of times, allowing the glue to dry between applications. After the last application of glue, take a patch, remove the backing, and stick it on the inner tube. Press it home, working from the centre outwards. When you are confident that the glue is dry, carefully remove any further film attached to the patch.
Step 5b: replacing the tube
Alternatively you can remove the punctured tube and take it home to repair at a later date. You can then instead choose to replace the punctured tube with a new one. This is preferable whilst on a ride as it is quicker and more convenient, especially if you are having to repair a flat in the cold and rain.
>>>> Cycling in the rain: How to survive it
Step 6
Check that there are no further holes in your inner tube. Then carefully run your fingers around the inside of the tyre to check there is nothing else penetrating the tyre. It’s usually possible to make a visual check of the tread while doing this.
Step 7
Inflate the (patched or replacement) inner tube slightly so it just becomes round in shape. This helps stop it pinching against the rim when you put it back in.
Step 8
Refit the tyre. Make sure the tread is pointing the right way — there should be arrows on the sidewall indicating the ‘direction of travel’. Some tyres are unidirectional and can be fitted in any direction. Put the valve in the valve hole, and feed the inner tube into the space between the tyre and the wheel rim.
Step 9
When the inner tube is all in, twist the tyre back into place, starting at the valve. Try to finish directly across from the valve as the tyre will be looser there. If it gets difficult, let a little air out of the inner tube. Check there are no bulges and that the tube isn’t pinching under the tyre bead. Try not to use tyre levers — they are likely to cause another puncture!
Step 10
Pump up the tyre to the correct pressure and refit the wheel into the bike securely. Close the brake quick release lever or reattach the brake cable. If you have mended a rear wheel puncture, get someone to hold the bike up, and go through the gears. Check that the wheel spins freely and the brakes work correctly.
Valve types
There are two types of valve with bike inner tubes: Presta and Shrader. A Shrader valve is the same as you’ll find on a car tyre and to inflate it you simply have to use a pump with a compatible adapter. To deflate it you have to push a little pin found inside the valve. Presta valves are thinner with a small captive nut found near the top. To inflate you need to unscrew the captive nut fully before using a pump with a suitable adapter. To deflate you unscrew the captive nut, then push it ‘in’ towards the base of the valve.
Further Tips
If the hole in the tyre is large, this may cause the inner tube to bulge through the gap, like a hernia. If this is the case, replacing the tube will just result in another puncture. The solution is to reinforce the hole, with an old piece of tyre from the inside. In desperate situations we have even seen energy gel wrappers used for this purpose. This solution should only be used to get you home or to your nearest bike shop: don’t ride on determined to hit your mileage target only to get more stranded when the tyre completely fails.
Check your spare tubes have the correct valves and that they’re long enough for your rims. People often upgrade wheels to deep section rims, but forget to get new spare tubes with longer valves.
Things to carry on any ride
Tyre levers
Two (or more!) spare inner tubes
Patches/repair kit
Some bits of old tyre to reinforce big holes
A pump
A mobile phone: if all else fails, get a lift home before hypothermia sets in
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