Learn it before you need it
Almost every rider gets a puncture sooner or later. The repair is not difficult once you have done it a couple of times, but it is much easier to learn at home in good light than beside a road in the rain. Try it once on a spare tube or an old wheel so the steps feel familiar.
This article describes the general process for a standard tube-type tyre. Bikes differ, including their wheel fastenings, brake types and tubeless setups, so follow the manufacturer’s instructions for your own bike and tyres. If you are unsure, a bike shop can fix the flat or show you how.
What you need
- A spare inner tube of the right size and valve type for your tyre, or a patch kit.
- Tyre levers.
- A pump or inflator that fits your valve.
- Any tools your wheel fastening needs. Many wheels use a quick release or thru-axle, and others need a spanner or hex key. A small multi-tool kit often covers these.
- Optionally, gloves and a cloth for cleaning hands and the rim.
Carrying these items is the core of roadside repairs. Most riders put them in a small saddle bag or pocket.
Step 1: get somewhere safe
Move well away from traffic to a stable, flat, well-lit place. If you cannot stop safely at the roadside, keep walking to a safer spot. Do not repair a tyre in a position where you could be hit.
Step 2: remove the wheel
Turn the bike upside down or lean it securely. Before removing a rear wheel, it often helps to shift the chain onto the smallest rear sprocket, which makes refitting easier. If you have rim brakes, you may need to open the brake release to give the tyre room to pass. If you have disc brakes, avoid squeezing the brake lever while the wheel is out, as this can make the pads close together. Open the quick release or loosen the axle as the maker describes, then lift the wheel out.
Step 3: let out the air and unseat the tyre
If any air remains, release it by opening the valve. Squeeze the tyre all around to loosen it from the rim. Push one tyre lever under the edge of the tyre, called the bead, and hook it onto a spoke. Insert a second lever a short distance away and slide it along to lift the bead over the rim. Work carefully so you do not pinch the tube with the levers. Once one side is off, you can usually pull the tube out.
Step 4: find the cause
This step is the one that matters most. If you simply fit a new tube without finding what caused the flat, it is likely to puncture again.
- Check the tyre inside and out. Run your fingers carefully along the inside of the tyre, taking care of any sharp object, to feel for a thorn, glass, a wire or a staple. Check the outside tread too.
- Check the rim. Look at the rim tape, the strip covering the spoke holes, to make sure it is in place and not worn or shifted. A spoke end poking through can puncture the tube.
- Look at the tube. If you can find the hole in the tube, it tells you where on the tyre to search. Inflating the tube slightly and listening or feeling for escaping air can help. A hole on the inner side of the tube points to the rim, while one on the outer side points to the tyre. Two small parallel holes, often called a snakebite, can suggest the tube was pinched, which may be due to the tyre being underinflated.
- Check the valve. Sometimes the problem is a faulty valve rather than a hole.
Remove whatever caused the puncture. A careful tyre inspection before every ride makes it more likely you will spot embedded debris before it works through.
Step 5: fit the new tube or a patch
A new tube is the quickest option, especially on the road. Patching the old one is a good use of time at home or if you have no spare.
- New tube: Inflate it just enough to give it shape, so it does not twist. Put the valve through its hole in the rim, tuck the tube inside the tyre, and check that it is not folded or trapped.
- Patch: Follow the kit’s instructions. This usually means roughening and cleaning the area, applying glue, letting it dry as directed, then pressing the patch on firmly. If the tube has a large tear, a bad valve or several holes, replace it rather than patching.
Step 6: refit the tyre
Start at the valve and press the tyre bead back inside the rim by hand, working around. The last section is usually the hardest. Try to push it on with your thumbs rather than levers, because levers can pinch the tube. Check along the rim edges to make sure no tube is trapped between the bead and the rim.
Step 7: inflate and check
Inflate the tyre gradually to the pressure range printed on the tyre sidewall or recommended by the maker. Using a pump with a gauge is helpful. Look at the tyre as it fills: it should sit evenly on the rim without bulges. If it does not, let the air out and reseat it.
Step 8: refit the wheel
Put the wheel back in the frame or fork, making sure it is seated fully. Close or tighten the fastening as the maker instructs, close the brake release if you opened it, and spin the wheel to confirm it runs freely. Do a wheel retention check and test the brakes before you ride off. If it was the rear wheel, make sure the chain sits correctly on the gears.
Common mistakes
- Failing to find the cause of the puncture.
- Pinching the tube with tyre levers.
- Fitting the tube twisted or folded.
- Leaving the tyre unseated and bulging.
- Riding with the quick release or axle not properly secured.
- Squeezing disc brake levers with the wheel out.
- Underinflating, which makes pinch flats more likely and can affect tyre tread and grip.
When to ask a shop
If you get repeated flats with no visible cause, if the tyre is cracked, cut or badly worn, if the valve is damaged, or if you ride tubeless and are not sure how to repair it, take the bike to a shop. Riding on a damaged tyre is a safety risk, and a mechanic can usually spot the problem quickly.