HOW TO FIX A PUNCTURE ON THE ROAD: THE STEP-BY-STEP GUIDE EVERY CYCLIST NEEDS

I was 45 km from home, somewhere on a back road in Wicklow with exactly one bar of phone signal and a rear tyre that had gone from rideable to completely flat in about eight seconds. No spare tube. No pump. I had left both in the kitchen because I was "only going out for a quick one." The walk home took three and a half hours, most of it in cycling shoes on tarmac, and by the end I had made two decisions. One: I would never leave the house without repair kit again. Two: I would actually learn how to use it properly.

Here is the thing nobody tells you about punctures. They are not complicated to fix. A ten-year-old could do it with twenty minutes of instruction. But the first time you try it on a windy roadside with cold hands and cars flying past, every step feels twice as difficult as it should. The fix for that is not talent. It is practice.

This is the guide I wish I had read before that walk in Wicklow.

What to Carry on Every Ride

This is your non-negotiable kit. It goes in your saddle bag or jersey pocket on every ride, regardless of distance.

• One spare inner tube (correct size for your tyre width and valve type — Presta or Schrader, check before you buy)
• Two tyre levers (plastic, not metal — metal levers can damage carbon rims)
• A mini pump or CO2 inflator (ideally both — more on this later)
• A self-adhesive patch kit as backup (Parktool or similar — these weigh nothing and can save you if you puncture twice)
• A multi-tool with a chain breaker (not strictly for punctures, but if you are carrying a saddle bag, there is no reason not to have one)

If you run tubeless, add:

• A tubeless plug kit (Dynaplug or similar bacon-strip style)
• A spare inner tube — yes, even on tubeless, carry a tube. The sealant does not fix everything, and a tube inside a tubeless tyre is your last-resort option to get home.

The total weight of this kit is around 250-300 grams. There is no ride short enough to justify leaving it behind.

Removing the Wheel

This is the step that intimidates most riders, particularly the rear wheel. It should not. Once you have done it three or four times, it becomes automatic.

Front Wheel

1. If you have rim brakes, release the quick-release lever on the brake calliper to open the pads. On most Shimano and SRAM callipers, this is a small lever on the calliper itself. If you have disc brakes, skip this step.
2. Open the quick-release skewer (lever on the left side of the fork) or unthread the thru-axle. Thru-axles typically unscrew anti-clockwise — some have a lever, some need an Allen key.
3. The wheel drops out. Catch it.

Rear Wheel

The rear wheel has a cassette and derailleur involved, which makes it feel more complicated. It is not, if you do one thing first.

1. Before you stop, shift the chain onto the smallest cog at the back. This positions the derailleur out of the way and makes removal and refitting dramatically easier. If you have already stopped and the chain is on a big cog, you can still shift — pick up the back of the bike, turn the pedals by hand, and click through the gears.
2. Release the brake (rim brakes) or skip this step (disc brakes).
3. Open the quick-release skewer or unthread the thru-axle.
4. Push the derailleur body backwards with your right hand. This opens up space for the cassette to clear.
5. Lift the bike up and away from the wheel. The wheel drops. If it does not, check that the chain is on the smallest cog and the derailleur is pulled back far enough.

Here is where it gets really interesting: most people try to pull the wheel out. You do not pull the wheel out. You lift the bike off the wheel. The wheel stays on the ground. The bike goes up. This changes the entire dynamic and makes rear wheel removal feel effortless.

Replacing an Inner Tube: Step by Step

You have the wheel off. The tyre is flat. Here is the process.

Step 1: Remove the Tyre from the Rim

Deflate the tube completely by pressing the valve core (unscrew the tip on a Presta valve, press the pin on a Schrader). Squeeze the tyre beads together and push them towards the centre of the rim — this creates slack.

Insert a tyre lever under the bead of the tyre, about 10 cm from the valve. Hook it onto a spoke. Insert a second lever another 10 cm along and slide it around the rim. One side of the tyre should now pop off the rim entirely. You only need to remove one side.

If the tyre is tight and the lever will not slide, use two levers closer together and work in smaller increments. Forcing it risks pinching the new tube before you have even started.

Step 2: Remove the Tube

Pull the old tube out from inside the tyre, starting opposite the valve. When you reach the valve, push it through the rim hole and pull the tube free.

Do not throw the old tube away roadside. It goes in your pocket. You can patch it at home and keep it as a spare.

Step 3: Find What Caused the Puncture

This is the step most people skip. Do not skip this step. If you put a new tube in without removing whatever caused the puncture, you will puncture again within minutes. I have watched it happen more times than I can count.

Inflate the old tube slightly and listen for the hiss, or run it past your lips — your lips are more sensitive to airflow than your fingers. The location of the hole tells you where to search.

• Hole on the outer surface (the side that faces the tread): something penetrated from outside. Run your fingers carefully around the inside of the tyre, feeling for a thorn, piece of glass, wire, or flint embedded in the rubber. Be careful — whatever punctured your tube is sharp enough to cut your finger.
• Hole on the inner surface (the side that faces the rim): a rim tape issue. Check that the rim tape is covering all spoke holes properly.
• Two parallel slits (snake bite pattern): a pinch flat. Nothing embedded in the tyre — the cause was insufficient pressure. Check your tyre pressure before you ride next time.

Step 4: Fit the New Tube

Take your spare tube and inflate it just enough to give it shape — a couple of puffs from your mouth or one short burst from the pump. This prevents the tube from folding or pinching when you fit it.

Push the valve through the rim hole first. Then tuck the tube into the tyre all the way around, making sure it sits neatly inside without twists or bunching.

Step 5: Reseat the Tyre

Starting at the valve, push the tyre bead back onto the rim with your thumbs. Work outward in both directions from the valve simultaneously. The last section will be tight.

Here is the critical detail: push the valve up into the tyre before seating the final section. This ensures the tube is not trapped under the bead near the valve — one of the most common causes of an immediate re-puncture.

Roll the final section on with your palms. If you must use a tyre lever to seat the last bit, use it with extreme caution — it is very easy to pinch the tube between the lever and the rim.

Once the bead is seated, push the valve up, then pull it back down. Check both sides of the tyre all the way around — you should not see any tube bulging between the tyre and the rim. If you do, deflate, reseat that section, and try again. A tube caught under the bead will blow out the moment you inflate fully.

Step 6: Inflate

Inflate to the correct pressure. If you are using a mini pump, this takes a while. If you are using CO2, this takes about five seconds (more on both below). Check the sidewall of the tyre for the recommended pressure range, and if you want a more accurate number for your specific weight, use the tyre pressure calculator on the site.

Step 7: Refit the Wheel

Reverse the removal process. For the rear wheel: hold the derailleur back, lower the bike onto the wheel so the chain engages the smallest cog, close the quick-release or tighten the thru-axle, and re-engage the brake if needed. For the front: drop the wheel into the fork, tighten, close the brake.

Spin the wheel. Check that it sits straight and the brake is not rubbing. Ride.

Inflation: CO2 vs Mini Pump

This is one of the most debated topics in roadside repair, and the answer is simpler than the internet makes it.

CO2 Inflators

A CO2 cartridge inflates a road tyre to full pressure in about five seconds. They are small, light, and fast. The downside is that they are single-use and unforgiving. If you do not get a clean connection between the inflator head and the valve, you lose the entire cartridge in a burst of freezing gas.

A few things to know:

• 16g cartridges fill a standard road tyre (25-28c) once. If you run wider tyres or want a margin, use 25g cartridges.
• The cartridge gets extremely cold during use. Hold the inflator, not the cartridge. The metal will freeze to your skin.
• CO2 permeates through butyl rubber faster than air. Your tyre will lose pressure over the next 24-48 hours. Top up with a floor pump when you get home.
• Practice at home before you rely on one roadside. Buy a spare cartridge, take a wheel off, and go through the full process.

Mini Pumps

A mini pump is slower, requires effort, and most small ones struggle to reach full road pressure — you might get to 80-85 psi on a good day. But a mini pump never runs out. You can pump, rest, pump again. It always works.

The best roadside strategy: carry a mini pump and one or two CO2 cartridges. Use the CO2 for speed. Keep the pump as your failsafe.

If you can only carry one, carry the pump.

Tubeless Puncture Repair

Tubeless tyres handle small punctures differently. The sealant inside the tyre fills most small holes while you are riding — you might notice a brief hiss and a few spots of sealant on your frame, but the tyre holds pressure and you keep going. This is one of the primary advantages of tubeless.

When the sealant cannot seal the hole — anything larger than about 3 mm, a cut rather than a puncture, or sidewall damage — you need to intervene.

Using a Tubeless Plug Kit

1. Find the hole. Look for sealant spraying or bubbling. If the tyre is fully flat, inflate slightly with your pump and watch for sealant appearing.
2. Insert a plug strip into the insertion tool. Most kits use a rubber strip (sometimes called a bacon strip) loaded into a sharp metal needle.
3. Push the insertion tool straight into the puncture hole. This feels wrong — you are deliberately pushing something into a hole in your tyre — but the plug expands inside and seals the cut.
4. Pull the tool out. The plug stays in. Trim the excess flush with the tyre surface if the kit includes a cutting tool.
5. Inflate. The combination of the plug and the residual sealant should hold. Ride gently for the first few kilometres to let everything settle.

When the Plug Fails

If the plug does not hold, or the cut is too large to plug, your last resort is fitting an inner tube inside the tubeless tyre.

1. Remove the valve core from the tubeless valve (a valve core tool on your multi-tool works, or the small tool included with most tubeless valve kits).
2. Break the tyre bead from the rim. This is harder than with a clincher because the bead seals tightly. Use tyre levers firmly.
3. Remove the tubeless valve from the rim.
4. Wipe out as much sealant as you can — it will be messy. This is unavoidable.
5. Fit a standard inner tube exactly as described in the tube replacement section above.
6. Inflate and ride.

The tube will get coated in sealant. This is fine. It works. Clean everything properly when you get home.

Pinch Flats and Prevention

A pinch flat — sometimes called a snake bite because it leaves two parallel slits in the tube — happens when you hit a sharp edge (pothole, kerb, rock) with insufficient pressure. The impact compresses the tyre so hard that the tube gets pinched between the rim and the obstacle.

Pinch flats are almost entirely preventable.

Run the correct pressure for your weight and tyre width. This is the single most effective thing you can do. Too many riders inflate to "max pressure" printed on the tyre sidewall, which is a maximum, not a recommendation. Too many others ride on whatever pressure happens to be left from last week. Both approaches cause problems.

Use the tyre pressure calculator to find the right range for your weight and tyre width. Check pressure before every ride with a reliable floor pump. It takes thirty seconds and prevents the majority of pinch flats.

Wider tyres help. A 28c tyre at the correct pressure absorbs impacts that would pinch-flat a 23c tyre. If your frame and brakes have clearance, running 28c or even 30c is a practical upgrade that improves comfort and reduces puncture risk simultaneously.

Pick your line. On roads you know well, you already avoid the potholes. On unfamiliar roads, scan further ahead and adjust your line early rather than swerving at the last second. If you cannot avoid an obstacle, unweight the bike: rise slightly off the saddle, bend your elbows and knees, and let the bike move underneath you. This reduces the impact force on the tyre and rim.

Practice at Home

The roadside is not where you want to learn any of this. The cold hands, the traffic, the pressure of knowing your mates are riding away or your partner is wondering where you are — all of it makes a simple job harder.

Here is what I would suggest. Take your bike into the garden or the kitchen. Take the front wheel off. Put it back on. Do the rear wheel. Do it again. Time yourself. Then remove a tyre, pull a tube, put a new tube in, reseat the tyre, inflate. Do the whole process three times. By the third time you will be under ten minutes, and the mechanical steps will feel automatic.

Then do it once more with your CO2 inflator so you know exactly how the connection works, how fast the gas flows, and how cold the cartridge gets.

The next time you puncture on the road — and you will — you will fix it in eight minutes, get back on, and carry on with your ride. That is the difference between a minor inconvenience and a phone call asking someone to come and collect you.

The Kit Checklist

Before your next ride, check you have all of this in your saddle bag:

• Spare inner tube (correct size and valve type)
• Two tyre levers
• Mini pump
• One or two CO2 cartridges plus inflator head
• Self-adhesive patch kit
• Tubeless plug kit (if running tubeless)
• Multi-tool with Allen keys and chain breaker

Weigh it. It is under 400 grams. You will not notice it on the bike. You will absolutely notice when you need it and it is sitting on the kitchen counter.

Punctures are part of cycling. They are fixable, they are fast to deal with, and once you have done it a few times, they stop being stressful entirely. The riders who dread punctures are the ones who have never practised changing a tube. The riders who shrug and get on with it are the ones who have.

If you want to talk through kit choices, tyre setup, or anything else covered here, the Roadman Cycling community on Skool is where a few hundred riders are doing exactly that. Come and ask a question.