How to Change a Flat

Changing a flat is one of the most basic repairs on a bike—it only requires a minimal amount of tools and a certain amount of patience to learn. The tools you will need are tire levers, a new tube or patch kit (I recommend keeping both handy), and a pump to inflate your tire.

Tire levers come in many different sizes, shapes, colors, and materials. I prefer the plastic ones because they are lightweight and fit easily into my seat bag. In my saddle bag along with the levers: an extra tube as well as a patch kit, which give you more fixes in case you blunder an attempt at fixing a flat or happen to pick up more than one flat on your ride!


Your best defense against flats is using a floor pump with a gauge and airing up your tires to the recommended pressure before you go on a ride. In addition to a floor pump at home you will need to have an inflation device that you carry with you on your rides. These come in many forms like a hand pump, which is similar to a floor pump but much smaller and can usually be mounted to your bike.

When picking out a pump make sure that it will work with the type of valve that is on your bike. There are two types of valves, Schrader like the valve on a car tire and Presta, a French valve that is skinny, metal and more common to road and higher end bikes.

CO2 is another popular emergency inflation choice, it usually comes in a kit containing a cartridge and a head that attaches to your valve and also punctures the CO2 canister to inflate your tire. If you are new to CO2, I recommend asking a representative at your local bike shop to show you how to use it before trying it out on a ride.

After you have gathered all your instruments for this repair you are ready to conquer the inevitable flat tire. Let’s get started!

Order of repair:
Removal of wheel and inspection of tire
1. Remove the wheel from the bike.
2. Inspect tire for damage or cause of flat
3. Remove tire from wheel
4. Remove tube from tire (patch or replace)
5. Inspect inside of tire for cause of flat

Replacing tube and remounting wheel
1. Put tube back in tire
2. Mount one side of tire onto the rim
3. Mount opposite side of tire onto the rim of the wheel
4. Check between bead of tire and rim to make sure tube is not pinched
5. Air up tire slowly making sure that tire stays mounted on rim (don’t over fill)
6. Remount wheel to bike (make sure wheel is attached properly to bike and that brakes are in working order)

Removal of wheel and inspection of tire

1. Remove the wheel from the bike. You will either have a quick releasing mechanism or nuts that you will have to loosen to be able to remove the wheel. Removing your wheel may also require you to release your brakes; a type of quick releasing mechanism usually does this. If you are working on the rear wheel you will have to clear the wheel from the chain before removing.
2. Prior to removing the tire from the wheel, inspecting the exterior of the tire for slashes, large tears or punctures, glass, and thorns can help you figure out what caused your flat. If you have a large tear, slash, or puncture you may not be able to fix your flat by just replacing or patching a tube. So inspect your tire before you go through the trouble of changing out the tube—it will save you time and frustration.
3. It is time to remove the tire from the wheel. First you want to make sure all of the air is out of the tube by depressing the valve core. It is important to note the location of the valve stem when beginning removal of the tire. It is best to start removing the tire on one side of the valve stem and work away from the valve until you reach the opposite side of the rim. Then return to the opposite side of the valve stem from where you started and work towards the portion of tire you previously removed. The removal of the tire bead is accomplished by taking your tire lever, skinny end first, and putting it under the bead of the tire and leveraging the tire over the edge of the rim. After you pull the first section of tire over the edge of the rim put the hooked end of the tire lever around the nearest spoke. Then take a second tire lever a couple of spokes down and repeat the same action of leveraging the tire off the rim. Completely remove one side of the tire bead and flip the wheel over. Remove the opposite side of the tire by pulling the tire off the rim in the same direction that you removed the first bead.
4. Now that the tire has been removed from the wheel you can take the tube out of the tire. Be sure to properly dispose of your tube or save it to patch it later if you are not going to patch it now. If you are able to tell where your tube is punctured and how large the puncture is you can try patching your tube at this point.
5. It is important to inspect the inside of the tire for anything that may have punctured the tube. I recommend doing this with gloves on to avoid being cut or punctured by whatever may be still stuck in your tire. Remove any debris that you find.

Replacing tube and remounting tire

1. At this point you are ready to install your freshly patched or new tube into the tire. It is easiest to accomplish this task by adding a small amount of air to the tube, just enough to give it shape. Then proceed to place the tube into the tire matching up valve stem with the logo on the tire.
2. Remounting the tire to the wheel begins by placing the valve stem through the hole in the rim of the wheel. Remounting the tire is done one side of the tire at a time. This can usually be done by hand unless you have an exceptionally tight fitting tire; in this case using the tire levers to leverage the bead of the tire back onto the rim is acceptable. Take care to make sure the tube is not pinched between the lever and the rim or it will puncture!
3. After mounting the first side of the tire flip the wheel over to the opposite side. Begin installing the bead remembering to start on one side of the valve stem working your way to the opposite side of the wheel. Once half of the bead has been mounted go back to the opposite side of the valve stem from where you started and work toward the portion of tire just installed. The final portion of tire you are installing should be opposite the valve stem. When you are working the last portion of bead back onto the rim it maybe easy enough to do by hand or you may have to use your trusty tire lever to finish the job (watch out for the tube if you use levers).
4. Doing a final check on both sides of the tire to make sure the tube is not being pinched between the tire bead and the rim will keep you from getting a pinch flat when you air up your tire. Be thorough, it will save you time.
5. Now you are ready to air up your tire. On the side of most tires there will be a listing of the range of air pressure that is appropriate for your tire. Find this listing, usually given as a psi or bars measurement. If you have a gauge on your emergency pump you will be able to fill your tire to an appropriate pressure, if you do not have a gauge get enough air in the tire to get you to the nearest bike shop to air up completely. When using CO2 a 16-gram cartridge will generally fill one mountain bike tire to 30 psi or one road tire to 130 psi. When airing up your tire it is important to do so slowly making sure that the tire is staying seated on the rim and not busting off.
6. The remaining task of remounting the tire is the only thing standing in the way of getting you back on the road. Place the wheel in the dropouts and making sure it is centered; if it is the rear wheel, routing the chain correctly is necessary. Once the wheel is correctly installed you will need to tighten it in its final position using the quick release or nuts that were removed when taking the wheel off. It is important to make sure that your quick release or nuts are installed and tightened to the manufacturer’s specifications. The final step is making sure that your brakes are reconnected and in working order also to manufacturer’s specifications.
7. Now you are ready to ride!

Hoping your ride is flat-free,
Sara