How To Fix A Flat Bike Tyre – Fast!

When your ride goes flat, here’s what to do.

Jason Sumner |

Whether you ride on smooth pavement, rough gravel, or rocky singletrack trails, at some point your bike will get a flat tyre. That means you need to prepare yourself with both the necessary tools and knowledge required to fix the problem. Otherwise, bring some comfortable shoes, because you might have a long walk ahead.

Below, we detail everything you need to know to fix your flat. For tools, you should always carry tyre levers, a correctly sized spare tube, and an inflation device, be it a mini pump or CO2 cartridge. You may also want to get a patch kit or tyre plug, which can come in handy for certain riders.

Remove (or Plug) the Tyre

Normally, your first job in the event of a flat is to remove the tyre so you can assess the problem inside. But for riders with tubeless setups – all but standard in mountain biking, and becoming increasingly popular on gravel, cyclocross, and even some road bikes – you can often stop air loss with a tyre plug.

These kits come with a small strip of rubber and an insertion device, which allow you plug the hole without changing any hardware. Once you spot the hole and insert the rubber plug, re-inflate your tyre to the appropriate pressure and check to see if it’s holding air. If so, start riding again, and check the repair every so often to make sure it’s holding fast.

If the tyre plug doesn’t work, or if you’re not riding tubeless, you’ll need to remove the wheel. Keep your bike upright, and if it’s a rear-wheel flat, shift your drivetrain into the hardest gear. If you have rim brakes, which many road bikes still use, you may also need to loosen the brake. Next, position yourself on the non-drive side of your bike (opposite the chain) and either open the quick release or unthread the thru-axle to remove the wheel.

Now you can remove the tyre. Hook the rounded end of one tyre lever under the bead (the outer edge) of the tyre to unseat it. Fix the other end to a spoke to hold the lever in place and keep the unseated tyre from popping back into the rim. Then hook the second lever under the bead next to the first, walking it around the rim clockwise until one side of the tyre is off. You don’t need to completely remove the tyre.

flat tyre

Find the Culprit

Once the tyre is off, pull out the old tube (if applicable) and look for the source of the flat, which could be a thorn, piece of glass, or some other sharp object. Carefully run your fingers along the inside of your tyre and rim, making sure nothing sharp is left behind. Otherwise, you risk getting another flat. Also inspect the outside of the tyre, again looking for any foreign object that might still be stuck in the rubber.

If you’re using tubes and want to do a little detective work, pump some air into the old one to find the leak. Two holes side by side indicate a pinch-flat, where the tube gets pinched between the tyre and rim. A single hole is a sign that your flat was most likely caused by a sharp object.

Patch the Problem

If you’re the thrifty type who likes to reuse old tubes, or if you’ve gotten multiple flats on your ride and have no more spares, then you can patch your tube with a patch kit.

Start by cleaning the punctured area and roughing the surface with an emery cloth. For a glueless patch, simply stick it over the hole and press firmly. For a patch that requires glue, add a thin layer of glue to the tube and patch. Wait for the glue to get tacky, then apply the patch and press firmly until it adheres.

Install the Tube

Now inflate your new or patched tube just enough so that it holds its shape. This makes it easier to place inside the tyre. Next, with the valve stem installed straight through the rim’s valve hole, work the tyre back onto the rim with your hands by rolling the bead away from yourself. Try not to use levers to reseat the tyre, as you could accidentally puncture your new tube. When you get to the valve stem, tuck both sides of the tyre bead low into the rim and push upward on the stem to get the tube inside the tyre.

Check to make sure the tyre bead isn’t pinching the tube by gently pushing the tyre to the side as you work your way around the rim. Then inflate to the appropriate PSI and check that the bead is seated correctly. If everything looks good, reattach your wheel, making sure the quick release or thru-axle lever is on the opposite side of your drivetrain.

If you had a rear-wheel flat, lay the top of the chain around the smallest cog on your cassette and carefully push the wheel back into the frame. Close your quick release (and rim brakes if applicable) or insert the thru-axle back into the frame and hub and thread it closed. Finally, lift the rear wheel and spin your cranks once to make sure everything is back in place and operating smoothly.

If all is good to go, get back on your bike and enjoy the rest of your ride.

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