Bicycle Flat Tire Repair

Flat tires are by far the number one repair the average bicyclist will encounter. Flats always happen at the most unexpected time. Imagine being out for a ride on a nice sunny day. There is no wind and the route you chose has very little traffic. It’s just you, the open road, and the sounds of nature around you. While you are taking it all in you suddenly hear the terrifying sound of a tire blowout followed immediately by that riding on the rim feeling. If you carry the tools and equipment you need to repair flat tires this will only be a minor annoyance. Otherwise, a call for help (if you have your cellphone) or a long walk home will be your only choice.

You’ll need a small saddlebag with the following items:
  • Bicycle tire levers 
  • Tire pump or CO2 inflator and cartridges 
  • Spare tube 
  • Tire repair kit (optional) 
  • Wrenches for axle nuts (optional) 

The following steps for fixing a flat tire will get you back on the road in short order:
  • Remove the wheel from the bicycle. 
  • Remove the tube from the tire. 
  • Check the tube and tire to determine what caused it to go flat. 
  • Install a new tube. 
  • Re-install the wheel. 

Remove the wheel from the bicycle
Front Wheel - Release the quick release lever (or remove the axle nuts holding the wheel to the frame) and remove the wheel from the bike. Some bicycle brakes have a lever to release the brakes so the tire will clear the brake shoes. Since the tire is flat anyway this isn't a concern when removing the wheel, however you may want to release it now anyway so that you can put the wheel back on with the tire inflated.
Rear Wheel - Shift the rear derailleur to the smallest rear cog. Release the quick release lever (or remove the axle nuts holding the wheel to the frame). Lower the wheel and guide it out and away from the chain. Some bicycles have a hanger for the chain that makes the job slightly easier. The chain hanger is usually just a peg on the inside of the seat stay for you to hook the chain on. Again, if your bicycle's brakes have a brake release lever you may want to release it now so you can re-install the wheel with the tire inflated.  After removing the wheel with the flat tire, lay the bike down on its left side. Never lay it down on its right side where the chain, sprockets, and derailleurs are as they can be easily damaged.

Remove the tube from the tire
Remove the valve cap and the nut holding the valve stem in place if there is one.
Starting on the side of the tire that is opposite the valve stem, use a tire lever to get under the bead of the tire and pry it out.
Using tire levers to remove tire bead from rim.
You don't want to hook the tube with the tire lever because you could cause an additional puncture to the tube. You still need to determine the cause of the puncture and adding another puncture to the tube will make your job harder. The tire levers are made so they can hook to the spokes to hold them in place if necessary. You'll probably need a second tire lever (possibly a third one also) to get the bead off the rim far enough until you can get the rest of it off by hand. Try to remove the bead evenly until you have it off the rim on the whole circumference of the rim.
Tire with bead removed on the whole circumference of the rim.
Tire with bead removed on the whole circumference of the rim.
The tire should look like this after the bead is removed.
Once you have the bead of the tire off the rim on one side, you can remove the tube from the tire. Again, working from the side opposite the valve stem, pull the tube out of the tire, pulling the valve stem out of its hole in the rim last.  Once removed from the tire, you'll want to keep the tube oriented as it was in the tire. This will help you locate the possible cause of the flat tire easier.

Check tube and tire to determine what caused it to go flat
Keeping track of how the tube was oriented in the tire, inflate the tube slightly. This will help you find the leak. You will probably hear a hissing sound and feel the air escaping. Holding the tube close to your face may help you feel and hear the leak better. You can also add more air to the tube if necessary.  Once you locate the leak in the tube, try to find what caused the puncture by looking and running your fingers (be careful, you don't want to puncture your fingers too) inside the tire in same area that correlates to the puncture in the tube. With any luck you'll find what punctured the tube and be able to remove it, or you'll find a tiny hole in the inside of the tire where a thorn went through the tire and punctured the tube but didn't stay in the tire.  Check the outside of the tire as well, just in case part of what caused the puncture is still embedded in the tread on the outside of the tire.

Install a new tube
Take your new tube and inflate it slightly. You don't need to put much air in it, just enough for it to hold its shape.
Tube inflated slightly - just enough for it to hold its shape.
Tube inflated slightly - just enough for it to hold its shape.
 Insert the valve stem into the valve stem hole in the rim and work the rest of the tube into the tire, working on each side of the valve stem until you have the tube fully inserted into the tire. Make sure the valve stem is straight. If the stem is crooked, you can turn the whole tire slightly until it is straight.  Push the tire bead back into place behind the edge of the rim. Starting at the valve stem, push the bead of the tire back under the edge of the rim. Working on both sides of the valve stem, work your way around the tire until you have it worked onto the rim opposite the valve stem. Make sure that you don't pinch the tube between the rim and tire as it could get punctured. You can do most (sometimes all) of this by hand. Once you get to the point where you can't push the tire bead behind the edge of the rim by hand, use your tire levers to get the tire on the rest of the way. Again, be careful not to pinch the tube between the tire and the rim.  After the tire is back on the rim, check the valve stem again to be sure it is straight. If not, you should still be able to rotate the tire slightly on the rim until the stem is straight.  Inflate the tire until it is feels like it would when fully inflated. Optionally, you could use an air gauge to inflate the tire to the proper pressure. When fixing a flat on the road I usually don't bother with the air gauge, relying more on feel or observing how much the tire deflects when pushed against something hard like the edge of a curb or rock after the wheel is back on the bike. Don't panic if your pump won't get your tire to the recommended tire pressure. As long as you can get it to between about 80 to 90 psi on a road bike you'll be ok. When riding just be careful of potholes and railroad crossings.  Re-install the nut on the valve stem (if there was one) and install the valve cap.

Re-install the wheel
Reverse the procedure you used to remove the wheel to re-install it.

This procedure seems long when written out, however with practice it shouldn't take more than 10 to 15 minutes. The more flats you fix the easier it will become.

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