So you have a flat. Instead of reaching for the cell phone, why not learn the steps to fix it? Here’s how you can, without getting your hands (too) dirty. For the sake of simplicity, we’ll describe how to change the rear flat, since this is harder than the front.
Necessary Accessories:
- extra tube
- patch kit
- pump or CO2 inflation system
- tire levers (two or three)
The step-by-step guide:
- Don’t turn the bike upside down.
- Shift the bike into the smallest cog.
- Disengage the brake.
- Stand on the non-drive side of the bike.
- Open the quick release skewer.
- 5.1. Open the brakes so that the pads move away from the rim (not applicable for disk brakes)
- 5.2. Move the quick release lever to the open position.
- 5.3. Hold the lever while loosening the nut on the other end of the lever (you won’t need to do this for rear wheels)
- 5.4. When this nut is turned far enough for both sides of the skewer to clear the safety tabs on the fork, lift the wheel out of the dropout.
- With your left hand, grasp the top tube of the bike and lift the rear wheel off the ground. Since the quick release is open, the wheel will fall out the dropout.
- While still holding the frame with your left hand, reach your right hand down to the small tab found on the derailleur above the jockey wheel.
- Push the tab with you finger towards the ground. This will cause the chain to slack.
- Move the frame away from your body so that the chain falls off the cogset.
- Grab the wheel with your right hand and set the bike down with its non-drive side.
- Now that the wheel is off the bike, you can get one side of the tire off the rim. If the tire is old, you can probably do this with your thumbs. If it’s a new tire, or a tight fit, you will probably need tire levers to carefully pry the bead off the rim. You only need to take one side of the tire off the rim.
- Remove the tube, and inflate it to see what type of puncture you have. Inspect the inside and outside of the tire for obvious gashes or debris lodged in the tire.
- Take your new tube, and blow a small amount of air in to give it shape. Insert valve stem into the hole in the rim, and feed the tube back into the tire.
- Push the tire back on to the rim, being careful not to pinch the tube in between the tire and the rim.
- Inflate the tube.
Reinstalling the wheel:
- Put the wheel back into the dropouts with the wuick release lever on the left, or non-drivetrain side, of the bike.
- Hold the lever in the open position while tightening the nut on the right side of the bike.
- When you start to feel resistance, move the lever to the half open position and continue turning the nut.
- Once you feel that you have tightened the nut sufficiently , move lever into the fully closed position. This is trial and error. The trick is to make sure that the skewer is hard enough to close that it leaves an impression on your hand, but you don’t want it to be so hard that you can’t get it open again.
- Make sure the end of the lever is not pointing toward the front of the bike.
Congratulations! You have fixed a flat!