Maintenance – How to Prevent and Fix a Puncture

We have all had that sinking feeling. Flat tyres are something you accept with bike riding, but there are several ways to prevent and reduce the chance of a puncture on a bicycle tyre. Whether you are running tubeless tyres or an inner tube there is still a risk of a puncture, and several ways to repair a flat.

This blog post considers 7 Tips for preventing, fixing, and repairing a bicycle puncture on all kinds of wheel setups.

Prevent Punctures – Tyre Choice

The single most influential factor in preventing a bicycle puncture is your choice of tyre.

Not all bicycle tyres are made equal. Most confusingly, even those with the same name are often not of an equal quality level. Some tyres feature inbuilt puncture protection belts made of Kevlar or a similar fibre—these help to avoid penetration of the tyre and puncturing of the inner tube. When looking at tyre reviews and choices, look out for those tyres with inbuilt puncture protection.

It is worth noting that when you buy a new bike, the tyres are often one area of cost saving that the builder targets. Typically, the tyres on a new bike will be a 'B2B OEM Model'—this means they might be called something like 'Schwalbe Smart Sam' but they are in fact a cheaper grade tyre than if you were to buy the same named model of tyre from a retail outlet. Be aware of this and expect to need to change out the tyres that come on your new bike promptly to reduce the risk of punctures.

My current top tyre choices (January 2022) are:

• Road Bike: Continental Grand Prix 4 Seasons Road Bike Tyres 28c
• Gravel Bike: Panaracer GravelKing SK+ 38c Tubeless Ready Gravel Bike Tyres
• Mountain Bike: Maxxis Ardent Race EXO TR 29er Tubeless Tyres

Prevent Punctures – Sealant (Inner Tube or Tubeless Tyres)

Whether you are running tyres with inner tubes or tubeless tyres—it is possible to use sealant to prevent punctures—or more correctly, to cure punctures.

With inner tubes, the sealant can be inserted into the tube through the valve (by removing the valve core), or you can buy inner tubes with sealant already fitted. For tubeless bike tyres, the sealant is added to the tyre during the mounting process—read my post 'Top Tips for Tubeless Bike Tyres'.

In both the above cases, the choice of sealant makes a notable difference to whether the sealant will effectively seal the cut or intrusion into the tyre or inner tube. There are two main kinds of sealant—latex-based and water-based; both have advantages and disadvantages—principally that latex seals better but dries out more quickly.

My current preferred brand of tubeless sealant is Effetto Mariposa Caffelatex Tyre Sealant, whilst the best sealing inner tube choice I have used is Joe's No Flats Yellow Tubes.

Prevent Punctures – Kevlar Strips

As mentioned above, many of the best tyres now have inbuilt Kevlar puncture protection strips moulded into the tyre casing. However, it is also possible to retro-fit Kevlar protection in the form of Panaracer Flataway Liner Strips. These are less common now, but it is a clever way of preventing punctures with an inner tube set-up if you do not want to pay out for new tyres.

Fix Punctures – Emergency Sealant Repairs

Quick-fix sealant solutions such as GüP Tyre Sealant can get you back riding—fast. They come as an aerosol can filled with CO2 and latex sealant, and can be used on inner tubes, tubeless tyres, or tubular tyre set-ups.

To apply you simply unscrew the valve (for Presta valves only), and then push the can onto the valve. The air and the sealant fills the tubeless tyre or tube, and hopefully seals the puncture while also re-inflating the tyre.

The sealant can remain happily in the tyre or tube after you have made the repair—it mixes with latex sealants such as Stan's No Tubes; although it will eventually cure and dry up, it will be useful during its liquid life for fixing further potential flats.

With the popularity of disc brakes, thru-axles, and tubeless tyres, the time taken to change a puncture is often a lot longer than it used to be. For that reason, a canister of quick fix emergency sealant could save you minutes during a race, or save your sanity on a freezing winter ride...

Fix Punctures – Tubeless Tyre Plugs

Plugging or repairing a large hole in a tubeless bicycle tyre can be necessary when the hole is too large for the tubeless tyre sealant particles to fill on their own. The Sahmaurai SWORD 2.0 is a neat tubeless tyre reaming and plug system that fits securely inside your handlebar ends.

The Sahmurai SWORD is a two-part system. You use the reamer to clean out and ready the hole in the tyre; then you push the sword into the hole with a sticky plugging strip inserted. As you pull the sword back out of the hole the sharp inner surface of the sword's eyelet cuts the plug in half and leaves it within the tyre. Spin the wheel, and the sealant will hopefully do the rest.

Fix Punctures – Instant Patches

Instant puncture repair patches offer a quick repair to a punctured inner tube. You simply find the hole in the tube by re-inflating it when it is out of the tyre; then you gently roughen the surface with the sandpaper; then apply the patch like it was a plaster.

Instant patches have many advantages: they are easy to store, there is no glue, and they are quick. The disadvantage is that the adhesive on them is not as strong as on vulcanised patches—as a result they tend to leak air in the long term, especially with heat and the high pressures.

The Lezyne Lever Patch Kit is one of the best quality instant patch kits I have tested.

Fix Punctures – Permanent Patch Repairs

The most reliable and long-lasting repair of a punctured inner tube is to repair the tube with a traditional vulcanising puncture repair patch kit.

This is also the most complex and time-consuming solution to a puncture repair—which is why many people opt to simply replace the inner tube rather than fix punctured tubes. However, for those on a budget or those without the luxury of a box full of tubes (such as a touring cyclist) these kits are essential.

The process:

1. Find the hole in the tube by re-inflating the tube and listening for the hissing noise. If the puncture is really small so there is no audible hiss then fill a bowl with water and hold the tube down in the water—as you rotate the tube you should find a small stream of bubbles coming out of the hole.
2. Dry the tube and mark the puncture using the small crayon provided. Deflate the tube.
3. Roughen the surface with the sandpaper so that the glue sticks better.
4. Apply the vulcanising solution to the tube—spreading it out so that is creates a circle the size of the patch with the hole in the centre. Leave the solution to dry until it goes a cloudy colour.
5. Put the repair patch onto the glued area—pressing down very firmly and smooth it out from the centre of the patch outwards. Hold in place for at least two minutes.
6. If there is any glue around the edge of the patch grate some chalk onto it using the grater on the back of the plastic box—this will stop the tube trying to stick to the tyre when you put it back in.
7. Ideally inflate the tube and leave it overnight to see if the puncture has sealed properly, then re-fit the tube to the wheel. If you do not have this luxury just pop it back in the wheel, and hope.

This is a worthwhile skill to learn—especially if you are away from a bike shop or workshop for a long time and have a limited supply of tubes. Some steps of the process can be left out—such as marking the tube with the crayon and grating the chalk (some puncture repair kits do not have these).

N.B. Once the vulcanising glue is open it has a limited lifespan as it begins to cure. You can delay this by screwing the top on tight and wrapping the glue tube in a small plastic bag. Alternatively, if you have a box of tubes, just leave the punctured tubes until you have several to fix in one go—then use most of the glue in one repair session.

The Hutchinson Rep'Air Repair Kit is one of the best quality puncture repair patch kits I have tested.

"Do not mention the P word..."