Required Tools: tire levers (2-3), patch kit (patches, glue, sandpaper), pump.

Recommended Tools: tweezers or sharp pointed awl.

Types of flats:
Pinch cuts
Punctures
Blow outs

Pinch cuts
Inspect the tire before removing it to help determine what type of flat that you have, and to help save time finding the hole in the tube. The noise a flat makes can indicate what type you have. Pinch flats often make a short "whoosh" sound as the air in tube quickly escapes through the cut. A slow leak may be invisible and inaudible, as the small leak results in air loss over a long period of time (1 day or more). Punctures that are not slow leaks will make a hissing noise. Blow-outs result in a loud pop (like an engine backfire). Pinch flats are caused by the tube being 'pinched' hard enough between the rim and tire to cause a small cut in the tube. Pinch flats are usually a result of low tire pressure, but also caused by hitting a blunt object (pothole or curb) straight on. A pinch flat will sometimes cause a small (2-4mm) slit in the tube where it sits closest to the side of rim, but usually causes 2 small slits on opposite edges of the rim. These flats are difficult to patch because they are far enough apart to require either two patches or 1 large patch, and close enough together to make applying 2 little patches next to each other tricky.
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Punctures
Punctures are usually caused by an object poking through the surface of the tube. Sometimes a puncture can be caused by a spoke nipple or the end of a spoke poking through the tube from the inside. A rimstrip is used to protect the tube from the spoke ends and nipples. A tear in the rimstrip can allow a sharp edge to gradually cut a hole in the tube. Torn rimstrips should be replaced. Cloth rim strips are much better at protecting the tube from this type of puncture. Slow leaks are caused by a small object (glass, wire, pebbles, etc.) lodging in the tire tread and gradually working its way through the surface of the tube. If you have a slow leak and cannot see the hole, immerse the tube (with some air in it) into a bucket of water. Bubbles will indicate where the hole is. If you are out on the road with a slow leak you should replace the tube rather than try to patch it. It is important to find the cause of the puncture and remove it from the tire to prevent further punctures. Sometimes the foreign object that caused the puncture will not stay in the tire after it goes flat, but you should inspect the tire carefully on both the inside and outside surfaces until you are confident that there is nothing left in the tire to cause further flats. A puncture can also be caused by a small cut in the casing of the tire. A tube under high pressure will chafe against the sharp edges of a casing cut until it too has a hole in it. Tire cuts should be covered to prevent further punctures. For emergency repairs a 'tire boot' can be used for this. It is a short (2-3") section of an old tire that is cut out. When placed under the casing cut it blocks the tube from contacting the tire cut. Some people use folded dollar bills or other strong, flexible but not stretchy material. If a tire cut is big enough, it is not recommended to use a tube patch on it, since the patch is stretchy, and could eventually blow-out.
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Blow outs
Blow-outs are caused by the tire either coming off the rim at some point, or the tire casing failing. Tires that are old may be damaged by sunlight to the point where the sidewall becomes brittle. A sharp stone can cut through the casing at that point and cause the tube to push through and explode. Inspect a tire for casing cuts by looking for exposed threads in the sidewall. Leaving a high pressure tire in the sunlight for extended periods of time may cause the pressure to increase beyond its capacity causing a very loud explosion. When a tire is installed it is good practice to inspect that the tube isn't caught underneath the bead. Inflating a tube that is pinched underneath the tire bead will push the bead of the tire up as it expands. If the tire bead rises up in one spot the tire is not 'properly seated' and may jump over the edge of the rim causing the tube to explode. Blow-outs result in holes that cannot be patched simply because they are too large for a patch to cover. Also, the tire may need to be replaced after a blow-out.
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