A flat tire is the most common thing that will stop your ride. It is also one of the easiest repairs once you have done it once. You need two tire levers, a spare inner tube or a patch kit, and a pump. That is it.
What you need (carry this always)
- 2 tire levers (plastic, not metal — metal damages rims)
- 1 spare inner tube (the right size — check the sidewall of your tire for the size, e.g. 700×25-32c)
- Pump or CO2 inflator
- Optional: patch kit for a second puncture
Step-by-step: roadside tube replacement
1. Get the wheel off. Release the brakes (quick-release on the brake caliper or push pads apart). Open the wheel quick-release or axle bolt. On rear wheels, shift to the smallest sprocket before removing — it makes getting the wheel back on much easier.
2. Deflate completely. Remove the valve cap and press the valve core to release any remaining air.
3. Remove the tire. Starting opposite the valve, hook a tire lever under the bead of the tire and lever it over the rim. Hook the lever to a spoke. Use the second lever 4–5 inches away to work the bead off. Once one side is off, pull out the inner tube.
4. Find what caused the puncture. Run your fingers around the inside of the tire carefully — look for the sharp object still embedded. A thorn or piece of glass left in the tire will puncture your new tube immediately. Check the rim tape too — an exposed spoke hole is a common cause of mysterious repeat punctures.
5. Install the new tube. Put a small amount of air in the new tube so it holds shape. Seat the valve through the valve hole, then work the tube into the tire around the rim. Tuck it fully inside — no tube peeking out.
6. Seat the tire bead. Work the tire bead back over the rim with your thumbs, working away from the valve. The last section is tight — push with your palm heels. If it will not go, do not use a metal tire lever or you will pinch the new tube.
7. Inflate and check. Inflate to half pressure first, check the tire bead is sitting evenly around the rim (no tube bulging out), then inflate fully.
If you are patching instead of replacing
Find the hole by inflating the tube and listening or submerging it in water. Dry it, roughen the area lightly with sandpaper (included in patch kits), apply glue, wait for it to go tacky (60 seconds), then press the patch firmly for 30 seconds. Wait 2 minutes before reinstalling. A properly applied patch outlasts the tube.
Practice at home before you need to do it roadside. The first attempt takes 20 minutes; by the third time, it takes five.