What you need before you start
You will need a new tube that matches your wheel size and valve type. Check the sidewall of your current tire for the size — it will look like "700x25c" or "26x2.0". Write that down when you buy a replacement, because the staff at the bike shop will ask. You also need a tire lever (a flat plastic or metal tool that pries the tire off the rim) and a pump. Most bike shops sell tire levers in packs of two for a few dollars. If you have quick-release wheels, you can remove them by hand; if you have bolt-on wheels, bring an adjustable wrench or the correct socket.
Lay the bike on its side on a clean, flat surface. If you are working on the rear wheel, shift the chain to the smallest cog first — this gives you more room to work. Have your new tube, tire levers, and pump within arm's reach.
Key Takeaways
- Buy a replacement tube that matches the size printed on your tire sidewall and the valve type of your current tube (Presta or Schrader).
- Remove the wheel, then use a tire lever to pry one side of the tire off the rim and pull out the old tube.
- Check inside the tire for thorns, glass, or sharp objects before installing the new tube, or the same puncture will happen again.
- Partially inflate the new tube before seating it in the tire, then work the tire bead back onto the rim by hand and finish inflating.
- Reinstall the wheel, making sure the brake pads are centered and the quick-release or bolts are tight.
Remove the wheel and deflate the tire completely
If the tire still has air, open the valve by turning the small cap counterclockwise and pressing the valve stem until all air escapes. For a quick-release wheel, open the lever on the side of the hub and unscrew the opposite side by hand until the wheel lifts free. For bolt-on wheels, use your wrench to remove the axle nuts on both sides, then lift the wheel away from the frame.
On the rear wheel, you may need to pull the derailleur back and lift the chain out of the way. Set the wheel on a clean surface so the tire does not pick up dirt.
Pry the tire off the rim using a tire lever
Insert the flat end of a tire lever under the tire bead (the edge of the tire that sits on the rim) about 6 inches from the valve. Pry gently until the tire lip pops over the rim edge. Slide the lever around the rim to free one full side of the tire, then remove the old tube completely.
You do not need to remove the tire entirely — just one side. Leave the other side seated on the rim so you have a clean workspace. If the tire is very tight, use a second lever to help, but do not force it or you may crack the rim.
Inspect the inside of the tire for damage
Run your fingers slowly along the inside surface of the tire, feeling for thorns, glass shards, or sharp objects. This is the most important step. If you skip it and the same object is still lodged in the tire, your new tube will puncture in the same spot within a few miles.
If you find something, mark the location with a pen on the outside of the tire so you can inspect that area of the rim tape as well. Check that the rim tape (the protective strip covering the spoke holes) is not torn or missing. If it is damaged, the spoke ends will puncture the new tube. Rim tape is inexpensive and takes five minutes to replace, so do it now rather than having another flat.
Install the new tube and reseat the tire
Inflate the new tube just enough so it holds its shape — about 20 to 30 percent full. This prevents twists and pinches when you seat it in the tire. Insert the valve stem through the rim hole first, then tuck the tube evenly around the inside of the tire all the way around the rim.
Starting opposite the valve, use your hands to roll the tire bead back onto the rim. Work your way around in both directions toward the valve. The last section near the valve will be tight — push the valve stem up into the tire to give yourself slack, then roll the final section of bead onto the rim. Do not use tire levers for this step; they can pinch the new tube. If the tire will not seat by hand, let out a little air and try again.
Inflate the tube to the correct pressure
Check the sidewall of your tire for the pressure range — it will say something like "80–130 psi" or "2.5–4.0 bar". Inflate to the middle of that range for a smooth ride, or toward the higher end if you weigh more or ride on rough roads. Use a pump with a pressure gauge so you can see when you have reached the target.
As you pump, watch the tire bead on both sides of the rim to make sure it is seating evenly. If one side bulges outward more than the other, stop, let out a little air, and work that section of the bead back into place by hand. Then resume inflating. A properly seated tire will have an even gap between the tire and the rim all the way around.
Reinstall the wheel and check your brakes
For a quick-release wheel, thread the axle back into the frame by hand, then close the quick-release lever firmly. It should require real pressure to close — if it swings shut easily, the wheel is not tight enough and will come loose while you ride. For bolt-on wheels, insert the axle through the frame and hand-tighten the nuts, then use your wrench to tighten them fully.
Spin the wheel to make sure it does not rub on the brake pads. If it does, the wheel is not centered in the frame. Loosen the quick-release or bolts slightly, center the wheel by eye, and tighten again. Squeeze the brake lever a few times to confirm the brakes work. You are ready to ride.
Frequently Asked Questions
How do I know if my valve is Presta or Schrader?
Schrader valves look like car tire valves — they are thick and have a removable cap. Presta valves are thin and have a small metal lock nut at the top that you must unscrew before inflating. Check your old tube or the valve on your wheel to see which type you have, then buy a matching replacement.
What if the tire bead will not seat no matter what I do?
The tire may be too tight for the rim, or the bead may be twisted. Let out all the air, remove the tube, and try rolling the tire bead back onto the rim by hand without the tube inside. If it seats easily, the problem is the tube — try a different brand or size. If the tire itself will not seat, the rim or tire may be damaged and you should take it to a bike shop.
Can I patch the old tube instead of replacing it?
You can, but only if the puncture is small and you have a patch kit. Patches work best on slow leaks from tiny holes. If the tube has a large tear, a pinch flat (two holes close together), or a valve leak, replacement is faster and more reliable. Patch kits cost a few dollars and are worth carrying on long rides, but for a tube you just removed, replacement is usually the better choice.
Do I need to remove the tire completely?
No. You only need to pry one side of the tire off the rim to access the tube. Leaving the other side seated keeps the tire clean and makes reinstalling it easier. Only remove the entire tire if you are replacing it or if the rim tape needs work.