FIXING A FLAT TIRE

At some point you will need to fix a flat tire. Here is what to do.

Required Tools

1) a good lightweight hand pump

2) a set of tire levers, also known as "tire irons" (usually made of plastic )

3) a patch kit

4) a spare tube

Are a patch kit and a spare tube both necessary? It is generally faster to replace the tube with the spare, but once your spare tube is flat, you will need the patch kit for sure. Optional tools are a tire pressure gauge, a grease pencil to mark the spot of any punctures, and a cleanup rag.

Inspect the Outside of the Tire

First, get the bike well off of the road and in a safe and comfortable location (out of the sun during the summer). Use the quick release to remove the tire from the bike. If the rear tire is flat, put the rear gear on the smallest cog for easier removal and replacement. A rear tire may have to be pushed towards the front of the bike before it will lift off, and the derailleur can be pulled to the rear to clear it. You will probably need to release the brake cable as well. Turn the wheel while looking for signs of a puncture. If you find an obvious chunk of glass or a nail, you are in luck!

Remove the Tube

Insert a tire iron between the tire and the rim on the side of the wheel furthest from the value, and lock the tire iron onto a spoke. Insert another tire iron into the newly opened gap between the tire and rim and move it a few inches down the wheel, locking it to another spoke. Now you can insert the third tire iron and completely loosen one side of the tire all the way around. Then pull the tube completely out. The valve stem may be difficult to remove.

Inspect the Inside of the Tire

Before doing anything else, use your fingers to carefully trace the inside of the tire casing to feel for any pieces of glass or wire that may have punctured the tube. If such a object is there and is not found, it will quickly puncture the tube again. If such an object is found, its location will indicate the location of the leak in the tube.

Inflate the Tube

Inflate the tube with the hand pump. If it won't inflate, you have a large leak that should be easy to locate, or the valve itself may be damaged. You may be able to locate the source of the leak by rotating the tube near your ear and listening for escaping air. If that does not work, you can pass the tube near the surface of your tongue in hopes of the feeling the escaping air. Once the puncture is found, it is easy to lose sight of its location. Some patch kits include a piece of crayon to mark the spot.

Find the Puncture

It is very important that you find the source of the puncture, either by visual inspection of the outside of the tire, manual inspection of the inside of the tire, or by locating the leak on the tube itself. Tires normally don't go flat by themselves, and if you don't find the source of the puncture, your spare tube will quickly be punctured again. Don't proceed until you have accomplished this step and removed the source of the puncture from the tire.

Put the Tube Inside the Tire

Your tire should be completely off the rim on one side. Lightly inflate your spare tube and push the valve thru the hole in the wheel. After making sure the valve is correctly in the hole, start tucking the tube into the tire all the way around, keeping it from getting twisted.

Put the Tire Back

Seat the tire at the valve first, lifting the valve a little (pushing the valve stem back into the valve hole) to allow the tire to fit under it. Then start seating the tire around the rim, using both hands ( and not the tire levers) to pop the tire onto the rim. The tire will get very tight as the last little bit remains off the rim. Remain determined and press hard with your thumbs until the tire pops into place. Visually inspect the tire/rim junction on both sides of the wheel to make sure the tube is not pinched between the rim and the tire. You can inflate and deflate the tire to avoid pinches and poorly seated tubes also.

Inflate the Tire

Use your hand pump to inflate the tire. If you don't have a tire gauge, use your judgment about when to stop. You don't want to over inflate and burst your spare tube at this point.

Remount the Wheel

Put the wheel back on the bike, making sure the wheel is true and does not rub against the frame or brakes. Tighten up the quick release and be sure to redo your brake cables if you loosened them.