Changing a Flat Tire

Feb 8th, 2019

Every cyclist should know how to fix a flat tire, and the good news is that it doesn’t take much! Practice once or twice at home and you won’t be intimidated by a roadside repair. Be patient and get it right the first time — there’s nothing worse than “fixing” a tire twice!

First of all, make sure you have the key supplies close at hand. An extensive list of tools you might consider carrying can be found here, but for a flat, you’ll need:

  • A spare tube or patch kit
  • Tire lever
  • Pump or CO2 inflator

It’s often easiest to flip a bike over onto its bars and saddle (though if you’re heavily loaded, this can require removing bags and it might be easier to keep things right-side-up), then loosen the quick release or thru-axle to remove the offending wheel. Using your thumbs, press the tire “beads” (the edges) into the center channel of the rim, then either peel the tire off with your hands or use a tire lever to hook a bead and slip it over the rim. If your bike has Presta valves, don’t forget to unscrew the lock nut first.

With the tire off the wheel, remove the tube and pump it up a bit to find the puncture, listening and feeling for leaking air. Depending on the size of the leak, you can either patch the hole or opt to replace the tube entirely. Patch styles include those with a bit of glue or pre-glued sheets, and either work well if you follow the directions. Lightly sand the area around the hole for good adhesion, apply pressure to the patch, and let the glue set.

Ready to put the fresh (or freshly patched) tube back in the tire? Not so fast! Run your hand around the inside of the tire in case a thorn is still inside, and check the outside for any sharp objects looking for a second act. Then insert the tube in the tire and pump it up just a bit — it’s easier to handle if it holds its own shape.

Punctured tire illustration by Daniel Mrgan

Align the valve stem and slide it through, then get one tire bead onto the rim — the first one is easy. You can usually get much of the second bead on by hand, but a tire lever is extremely helpful for the final 20 percent. Be sure to push as much of the bead as possible into the center channel, it’ll give you more to work with!

With the tire back on the rim, re-inflate the tire to your preferred pressure with a pump or CO2 inflator, reinstall the wheel, and get back on the road!

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