Every road cyclist gets punctures. The difference between a five-minute stop and a long walk home is what you carry and the order you do things in. This guide covers both tubed and tubeless tyres, using the repair instructions published by Park Tool and by the makers of the tubes, plugs, pumps and CO2 inflators you are likely to carry.

Key Takeaways

• Get off the road first, then find the cause. Park Tool notes the object that caused the flat is often still in the tyre, so check the tread and feel inside the casing before fitting a new tube.
• Replacing the tube is, in Park Tool's words, "always the safest and most reliable procedure". Patch the punctured tube at home.
• Glueless patches are a temporary fix. Glue (vulcanising) patches last longer but do not work on TPU tubes.
• For tubeless tyres, let the sealant work, then use a plug for holes it cannot seal. If you have to fit a tube, remove the tubeless valve first.
• A 16 g CO2 cartridge puts about 88 psi (6.0 bar) into a 700x28C tyre, according to Topeak's chart. That is above the 5.0 bar hookless limit for 25–29 mm tyres, so control the flow.

What to Carry

Step 1: Get Safe and Find the Cause

Stop where you and your bike are fully off the road, ideally with a clear view of traffic. Then:

1. Remove the wheel. Shift to the smallest rear cog first if it is the rear wheel.
2. Find the hole. Inflate the tube slightly and listen or feel for escaping air. Note where the hole sits relative to the valve; that tells you where to look on the tyre.
3. Find the cause. Park Tool's repair guide stresses checking the tyre: inspect the tread and carefully run your fingers around the inside of the casing. Glass, wire and thorns often stay embedded and will puncture a new tube immediately.
4. Read the damage. A single small hole is a thorn or glass. Two parallel slits ("snakebite") mean a pinch flat from low pressure or a hard impact. A visible cut in the tyre may need a boot.

Fixing a Tubed Tyre: Swap the Tube

Park Tool's procedure for tyre and tube removal and installation, adapted for the roadside:

1. Deflate fully and push both beads into the centre channel of the rim to create slack.
2. Lever off one bead. Insert one lever opposite the valve, hook it to a spoke, then insert a second lever 25–50 mm away and slide it around. Park warns never to use a screwdriver.
3. Remove the tube, valve last.
4. Check the rim tape is covering every spoke hole.
5. Put a little air in the new tube so it holds its shape, then fit the valve and tuck the tube into the tyre.
6. Refit the bead by hand, finishing at the valve. Push the valve up into the tyre so the bead can seat beneath it. Avoid levers if you can; they can pinch the new tube.
7. Check both sides that no tube is trapped under the bead, then inflate gradually and confirm the bead line sits evenly all the way round.

Patching: Glueless vs Glue, and TPU Tubes

If you puncture your spare as well, you will need to patch.

TPU spare tubes save weight and space. Pirelli's P ZERO SmarTUBE weighs 35 g for 23–32 mm tyres, Schwalbe's Aerothan Road 51 g, and Tubolito's S-Tubo-Road 26–28 g (disc-brake bikes only). Check how you will patch yours, because standard glue kits will not work.

Schwalbe adds a TPU-specific caution: only inflate an Aerothan tube with CO2 once it is fitted in the tyre.

Big Cuts: Booting the Tyre

A cut in the tyre casing lets the tube bulge through and burst. A boot covers the cut from the inside so you can ride home.

1. Clean the inside of the tyre around the cut.
2. Place the boot (Park TB-2 is 76.2 x 44.4 mm) centred over the cut.
3. Fit the tube carefully so it holds the boot in place, and inflate to a moderate pressure.
4. Ride home gently and replace the tyre.

Park describes the TB-2 as a temporary repair and says it is not meant for tubeless tyres without a tube. A banknote or energy-bar wrapper is a common improvised substitute, but treat any boot as a get-home measure only.

Tubeless Punctures: Sealant, Plugs, and When to Fit a Tube

With tubeless tyres, most small punctures seal themselves. When you hear hissing:

1. Rotate the wheel so the hole is at the bottom, letting sealant reach it. Ride on gently if it seals.
2. If it keeps leaking, plug it. Use the plug tool to push a plug into the hole, following the maker's instructions.
3. Re-inflate and let the sealant set around the plug.

When to fit a tube instead. If the cut is too large to plug, fit a tube. Schwalbe and Continental both say to remove the tubeless valve first, and Schwalbe adds to wipe out the sealant. SILCA advises pulling out any sharp-tipped plugs before you fit the tube, so they do not puncture it.

Inflating: CO2 vs Mini Pump

Mini pumps never run out. Topeak's RaceRocket HP reaches 160 psi, weighs 77 g and moves 22.2 cc per stroke. Lezyne's Road Drive is rated to 160 psi and its Pressure Drive to 120 psi. Expect to work hard for higher pressures.

CO2 is fast and compact, but each cartridge is a fixed dose:

That last figure matters for hookless rims. Schwalbe's ETRTO table limits 25–29 mm tyres to 5.0 bar on hookless rims, so emptying a full 16 g cartridge into a 28 mm tyre would overshoot it. Use an inflator with flow control and stop early, or top up with a pump.

Three more CO2 cautions:

• Cold. Genuine Innovations explains that cartridges get cold enough to cause frostbite; Lezyne's neoprene sleeve exists to insulate your hands. Hold the cartridge by its sleeve or wear gloves.
• Leak-down. Tubolito says CO2 escapes faster than air from both butyl and TPU tubes. Deflate and refill with a pump when you get home.
• Sealant. Continental and Schwalbe advise against using CO2 with tubeless sealant. If you have to, plan to refresh the sealant afterwards.

Frequently Asked Questions

Should I patch or replace the tube at the roadside?

Replace it. Park Tool calls replacement the safest and most reliable procedure. Carry a patch kit as backup if you puncture your spare.

Do glue patches work on TPU tubes?

No. Park says its VP-1 glue kit does not work on TPU tubes such as Tubolito and Aerothan. Use glueless patches or the tube maker's own patch kit.

How much pressure does a 16 g CO2 cartridge give?

Topeak's chart gives about 88 psi (6.0 bar) in a 700x28C tyre, 100 psi in a 25C and 120 psi in a 23C.

Can I use CO2 with tubeless sealant?

Continental and Schwalbe advise against it. If you must, refresh the sealant once you get home.

How do I fit a tube in a tubeless tyre?

Remove the tubeless valve, wipe out loose sealant, pull out any sharp plug tips, check the casing for the cause, then fit the tube as normal.

How long does a tubeless plug last?

Dynaplug says a correctly fitted plug can last the life of the tyre. Muc-Off is more conservative for road tyres: replace the tyre and limit pressure to 80 psi until you do.

What is a tyre boot?

A tough patch placed inside the tyre over a cut, so the tube cannot bulge through. Park's TB-2 measures 76.2 x 44.4 mm and is a temporary fix.

Which fix for which damage?

Final Checklist

Before your next ride, check you have: a spare tube that suits your rim depth, two levers, glueless patches that work with your tube type, a boot, a pump or CO2 with flow control, and a plug tool if you run tubeless. Practise a tube change at home once. Knowing the steps is what turns a puncture into a short stop.

Prevent the next one

• Check pressure before every ride. Low pressure is the main cause of pinch flats on tubed tyres, and tubeless tyres slowly lose air too.
• Inspect the tread after wet rides. Rain washes glass and flint onto the road, and small fragments work their way in over several rides. Pick them out with a small tool.
• Replace worn tyres. A thin, squared-off tread or exposed casing threads punctures far more easily.
• Refresh tubeless sealant at the interval your sealant maker recommends, because dried sealant cannot seal a hole.
• Check your spare. Spare tubes and patches carried for months can be damaged by tools rattling against them. Wrap them and replace anything that looks worn.

Sources

• Park Tool: tyre and tube removal and installation
• Park Tool: inner tube repair and tubeless tyre mounting and repair
• Park Tool TB-2 emergency tyre boot
• Topeak RaceRocket HP mini pump
• Schwalbe tubeless FAQ and Aerothan tubes
• Dynaplug Racer and Stan's DART
• Genuine Innovations: why CO2 cartridges get cold

Equipment mentioned in this guide

• Park Tool TL-1.2 tyre levers
• Dynaplug Racer tubeless repair tool
• Pirelli P ZERO SmarTUBE

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