Beyond general care for you bike, the first repair you are likely to face is a flat tire. Unlike a car, where you change the entire wheel, on a bike you replace just the inner tube. This is both economical and convenient because an uninflated tube not only costs much less then an entire wheel, it also takes up a lot less space. That makes it easy to keep one on hand or carry it with you on the road.
You’ll need 3 things for this job.
- spare tube
- tire tools
- bicycle pump
To being with, you need to remove the flat wheel from your bike. In the case of the front wheel this is simple, just open the quick release by lifting the arm and loosening the bolt until your tire pulls easily off the forks. It’s also helpful to loosen the breaks by squeezing the calipers (the part that grips the tires) by hand, and un-hooking the break cable. For the back tire you first have to disengage the chain. Press the derailleur lever to create slack and lift the chain off the rear gear set. Open up the back breaks as above. You can then open the back quick release and remove the tire and gear set from the rear fork.
Once your wheel is off, you’ll need a set of tire removal tools to get the tube out. Please don’t use screw drivers or other improvised tools as you are likely to puncture your tire, or worse yet your hand. Tire tools come in a set of two, and look like a cross between a small wedge and a hook. Typically made of plastic, they help you carefully pry the tire from the rim of your wheel without damaging it or yourself. Still, it takes some force and fineness. Here is how its done.
Use one of the tools to pry up the tire by slipping the wedge end between the tire and rim, and levering a small spot on the tire up and over the outer edge of the rim. Leave that tool in place. Sometimes the hook is designed in such a way that you can put it around one of your spokes to help hold it steady. Next take the second tool and using the hook end, work it under the tire next to the firs tool. Then slide the hook along the tire, lifting it up out of the rim as you go. When you get all the way around back to the first tool, the tire will be disengaged from the rim.
You can now remove the old tube from inside the tire, pulling the valve stem free last. Your stem should have a small nut on the outside of the tire keeping it in place. Be certain to remove that before trying to pull out the stem.
Get out your new tube and open it up. Inflate it partially, just enough to give it some shape. This helps when inserting it into the tire. Start with the valve stem first, inserting it fully through the tire, and securing it on the outside with the new nut that came with the tube. Hand tighten only. Use of any tools is likely to over-tighten and rip the stem off the tube, rendering it useless. Work the rest of the tube carefully under the tire and inside the rim.
Now it’s time to put the tire back on the rim. Again use one tire tool to wedge one part of the tire back up and over the rim. Leave that one in place and use the second to work your way around the wheel. This can get pretty tight at the end so watch your fingers. If you find the tube is in the way, you may have pre-filled it to far. Just let a little air out and continue.
Once you have the tire back on the rim, you can completely inflate the tube, or do so after re-attaching the wheel. For the back wheel ensure you are inserting it on the forks with the gear set on the proper side. Tighten the quick release and loop the chain back on the gears. Give the crank a few turns to ensure the chain is on the proper gear for your shifter settings.
For the front, make sure you attach the wheel with the rotation arrows on the tire (if present) facing the right way. Hand tighten the quick release and press the release arm in. Be sure to have the arm in line with the forks, as this minimizes the chance it will snag on anything. Finally, for either tire, re-secure your brake cables on the caliper fork, and test your breaks to ensure they are functioning properly.
Your done! Your bike is now back in business and you can keep rolling along.