Please Note: Do not use this procedure if you are not certain that you can complete it safely, or if it does not seem accurate. Skippity Whistles provides this information as advice, and cannot accept any liability from your usage of it.
Uh oh, the tire on the Orange Monster is flat.
How did it happen? What did you run over? What did you hit?
There’s no need to worry about any of things now. How it happened isn’t important: we just need to change the tire.
There’s a bit of a misnomer about changing bicycle tires, because you seldom actually replace the tire. We say we want to fix the tire, but it’s the innertube that’s actually flat.
Get a New Tube
So, take a look at the tire and hunt for the numbers that tell you the size of the tube you need to buy. A standard bicycle tire size is 26 inches, which is the circumference of the wheel, by 1.25, which is the diameter of the tube itself.
You can find the innertube at most bicycle stores, and even places like Target. It’s usually around five dollars.
You’ll need a bicycle pump, which, if you have a bicycle, it wouldn’t hurt to have anyway.
Remove the Tire from the Bike
First, we need to get the wheel off of the bicycle. On this bike, it’s the back tire, which make it a little bit tricky because of the chain. But, it’s probably safe to say that fifty percent of bike flat tires happen on the back wheel, so here goes.
First, we need to release the brake caliper to make room for the tire. Most bikes have a release like this one – simply squeeze the two calipers together to get slack in the cable, and then lift the cable out of the tray.
Older road bikes, like this Nishiki ten speed, have a toggle above the brake lever you can slide out of the way.
With the brake released, it’s time to remove the wheel.
Old bicycles had a nut-and-bolt axle that required two wrenches to remove. If you have one of those bikes, take a look at the video How to Remove the Wheels from an Old School bike, also on Skippity Whistles.
Newer bikes have a skewer, which makes life super easy. Once side of the skewer is simple a knurled nut – forget about that side. The other side has a lever. Pull the lever open, and now you can pull the tire out of the cradles on the frame.
As we remove the back wheel, the spring-loaded rear derailleur propels the chain along with it. Just keep going, the pull the wheel up and away from the frame.
Remove the Old Tire
Find the valve stem, remove the cap, and push in on the little post in the center. You might hear a tiny whoosh as the last of the air leaves the tire.
There are specific tools you can buy to help you remove the tire from the rim, but a couple of flat-bladed screwdrivers can work, too.
The tire has a bead on its inside edge that matches to a bead on the rim – that’s what keeps the tire straight.
Gently push your screwdriver over the edge of the rim, angled towards the tire. Push the blade against the tire to lift it up and out of the rim.
Keep that blade in place, and use another screwdriver to do the same thing about six inches away. Now slide the first blade along the rim, away from the other blade. The tire should rise out of the rim. Keep going until the tire pops over the side.
Now go back to the valve stem and push it straight into the tire. You can pull the valve, along with the innertube, out from inside the tire. We’re done with this one.
Install the New Tube
Before you install the new tube, run your fingers carefully along the inside of the tire to see if you can find what poked a hole in the old tube. If you find it, pluck it out. If you can’t, it may not be stuck in the tire, which means we’re okay.
Use the bicycle pump to shove a few blasts of air into the new tube. Don’t fill it – just give it enough air so that it looks, well, tubelike.
Starting with the valve stem, shove the tube over the rim and under the tire. Push the valve stem through the hole in the rim, and then pull it down from the outisde.
Now, gently push the tube into the tire.
You can fit the tire back into the rim with your fingers most of the way around, but you’ll eventually need to use the screwdrivers to pop it over the edge.
When you do use the blade, be careful not to pinch the new tube between the blade and the rim or the tire. If you pinch it, you could cause it to leak. Carefully pop the tire back into the rim.
Inflate the Tire
Connect your pump to the valve stem and pump away, taking the tire up the recommended pressure. If you have a compressor, be very, very careful to fill the tire slowly – these are thin tires that fill up really fast. Work the tire from side-to-side with your hands to make sure the tube fills up evenly.
Put the little cap back onto the valve stem.
Replace the Wheel
Left the wheel into the frame, with the gears on the same side as the derailleur. As before, the derailleur is spring-loaded, so it’s in an upside-down position now.
Turn the derailleur over with your hand as you drop the tire in. The chain will engage the gears, and will ride with the wheel down into position.
Slide the axle into the dropouts on the frame, working the wheel from side-to-side slightly, until it rests firmly against the back of the dropouts.
Flip the lever on the skewer, so that the wheel is firmly clamped in the frame.
Turn the bike over and set it on its wheels, and undo the brake release.
Now that you’ve got a good tube correctly mounted, you can pump the tire up to its full pressure – the pressure is marked on the side of the tire.
Test ride the bike briefly to make sure there’s no rubbing, which means the wheel isn’t pushed firmly against the dropouts, and that it shifts smoothly.
Congratulations! You changed your bike tire! you did it!