If you've been riding as long as I have, it's easy to assume that "Everyone knows how to fix a flat" That is why I have not covered this basic but essential repair sooner. Chalk it up to shortsightedness or arrogance. Either way, I apologize.

There are two types of tire repair. Changing a tire, and patching a tube. Most cyclists keep a good tube rolled up in their tool bag. Sometimes even pre coated with talc, so it can be mounted easier. In the case of a flat, they simply change the bad tube for the good one.

Others, like myself, keep both a spare tire and a patch kit. A good idea if you're on a long ride, and/or may face questionable roads. Essential if you are on an unsupported tour.

Changing it

Remove the tire with your hands alone, if you can. If it's on too tight, common with very high pressure tires or "low profile" racing rims, do NOT use a screwdriver or any other object that has an "edge", you'll just make another hole. Use plastic tire irons specifically made for removing bicycle tires.

To use the tire irons, slip one of the irons (smooth end) between the tire and the rim and, being careful not to pinch the tube between the tire and the iron, bring the lever down, prying the bead (the edge of the tire) over the rim. There is usually a "hook" cut into the other end of the iron. Hook it onto a spoke.

Take another lever and do the same thing about 6 inches or so away from the first one. If you have a third lever, hook the second one like you did the first and use the third lever about six inches on the other side of the first iron. Using your last iron, pry off the tire a little at a time, moving around and prying until you have enough of the bead off the rim to pull off the rest using your hands.

Once you have one edge of the tire off the rim, pull out the tube. If you use Presta type valves (the skinny ones, not the kind like on car tires), unscrew the ring holding it into the rim first!

When you have the old tube out, check the inside of the tire to make sure there is nothing that could cause another flat. Use a cottonball, rag, or your fingers (careful!) and feel the entire inside surface for anything sharp. Also, while you have it exposd, check the rim to be sure that all the spoke heads are covered, they can cut through a tube too!

Unroll the new tire, and putting just enough air into it to give it shape, slip the valve into it's hole.

Starting from the valve, carefully work the tire bead back onto the rim. Push the valve up into the tire or it may lift the tire off the rim when you inflate it. Also make sure that the tube does not get caught between the tire and the rim, or you may be in for a nasty suprise when you pump it back up! Screw the nut back on the valve if it's a presta valve tube. Snug, but not tight yet, and work the rest of the tire onto the rim.

When you have most of the tire on the rim it gets difficult, because everything is going to fit tight. To make it easier, let all the air back out of the tube and work the tire on. Use gloves to protect your hands and use the heel of your hands. Don't ever use any tools to mount a tire. Not even tire irons. You'll pinch the tube for sure and have to start all over again.

Be sure the tire bead is evenly set around the rim, on both sides.

NOTE: Please, when you do change a tube, roll up the old tube and take it with you. Don't leave it laying on the side of the road. Although that's where I obtain most of my spare tires from, it still doesn't make it right, Besides, it's littering and illegal (heavy fine). And it's not likely I will ever ride the same road you just did. so don't count on me picking up after you!

Patching things up

When you get home, or if you got another flat and already used your spare tube and, you'll need to patch the tube. here's how.

Inflate the tube to find the hole, or holes. Pump in a lot of air, you want the tube to be about one and a half to two times as big as the tire it fits into. Not only does this make the hole easier to find, it also gives you more time to find it.

Go around the tube holding it close to your ear or your lips and see if you can hear or feel the escaping air. If you can't find it, fill a sink with water and submerge the tube, working your way around a little at a time, until you see a telltale string of bubbles. Mark the spot with a piece of chalk.

Note that there may be more than one hole! If the flat was caused by you hitting a rock or pothole, called a "pinch flat" or "snake bite", there will be a pair of holes. Nails and other objects can sometimes cause two holes as well by punching through the side of the tube against the rim as it goes flat.

Once you have the hole marked, dry the tire completely if you had to get it wet, and get out the patch kit.

The patch kit should have the following items:

• Patches
• A tube of glue (Unscrew the cap and pierce the opening of the tube if it's new)
• Sandpaper or emery cloth

Now for the repair.

1. Use the emery cloth/sandpaper to roughen the tube around the hole(s). You can stretch the tube over your knee to make this easier.
2. Pump enough air into the tube to make it slightly larger than the tire it goes into, if possible. this will prevent the patch from having to stretch when it's used, and also assure that the patched spot will inflate to the same size as the rest of the tube when it is inside the tire.
3. Put a gob of glue on the hole(s) a little larger than a pea for the small patches, two peas for the large ones, and spread it around an area the size of the patch you're going to use. Let it dry about 5 minutes for "normal" air. shorter if the air is dry, longer if it's moist.
4. Peel off the foil backing from the patch being careful not to touch the exposed surface. If there is plastic covering the other side, leave it on. It will help prevent any excess glue from reacting with the tire casing.
5. Press the patch over the hole and press it on tight. Use a tire iron, screwdriver handle etc. to "iron" it on secure (another good reason to leave on the plastic). Hold it for a few seconds to assure a good bond.
6. Pump up the tube and check to see if the patch is secure and that there are no other holes.

That's it! If you're on the road, follow the instructions above to reinstall the tube and tire. If you're at home, roll it up with some talc and put it back in your tool bag.

NOTE: the glue that comes with the patch kits tend to dry out after the tube has been pierced opened the first time. Check these tubes periodically, to avoid surprises on the road!.