7. How to Fix a Flat Tire

How to use a patch kit to repair a tube. Also demonstrates how to remove and install a tire.

IMPORTANT: Nuts and bolts on your bike should always be tightened to the manufacturer's specifications.
How to Fix a Flat Tire
DVD Vol. 1 DVD Volume 1
This video is available on DVD


  • 03:25 - Don't smear the glue as long as is shown here (I got distracted reading the script).
  • 03:45 - Peel off the paper or plastic backing after the patch is applied.

Fixing a flat tire is one of the most common bicycle repairs. I personally recommend replacing a tube when you get a leak, but that is not always possible. If done properly, a patch will work just fine. Here’s how it’s done.

Required Tools

For this tutorial you’ll need a patch kit, a set of tire levers, and an air pump. Your patch kit should contain a few different patch sizes, sandpaper or a metal scraper, and a tube of glue.

Inspect Tire

With the wheel removed from your bike, inspect the outer surface of the tire to make sure there are no sharp objects like a thumb-tack or thorn stuck in the tread.

Remove Tire

Remove the valve cap and fully deflate the tube by depressing the valve stem with the hooked end of your tire lever. There are two main types of valve stems, a schrader valve and a presta valve. This tutorial is based on a schrader valve, but I will be covering the different valve types in another tutorial.

Now it’s time to remove your tire, one side at a time. Choose a section of tire that is away from the valve and hook one of the tire levers under the bead, directly in line with one of your spokes. Pry one side of the tire bead over the edge of the rim, and then hook the end of the tire lever to the nearest spoke. Insert another tire lever two spokes away from the first, and a third another two spokes away. Now the middle lever should fall out, and you can continue the process. When the tire is loose enough you can just run a tire lever around the rest of the rim to pull the whole side over.

After you have removed one side of the tire, the other side should come off very easily.

Inspect Tube

Now remove the tube from the tire, and try to keep track of where it was positioned in relation to the tire. Inflate the tube to approximately twice its original size. This will expand the hole making it easier to find.

Listen carefully to the entire circumference of the tube; you should hear a hissing sound that will indicate where the leak is. As a last resort you can submerge the tube in water and watch for bubbles, but you’ll want to avoid doing this as you’ll need the tube to be completely dry in order for the patch glue to work.

Once you’ve found the leak, take note of whether it is on the inner or outer side of the tube.

If the hole was on the outer side of the tube, inspect the inner surface of the tire in that spot to make sure the object that caused the puncture is not still stuck in the tire. Double check the entire inner side of the tire by running your fingers along the entire surface, feeling for obstacles along the way.

If the hole was on the inner side of the tube, inspect your entire rim to make sure there are no sharp burrs in the metal, and that the rim tape is properly protecting the tube from your spoke ends.

Patch Tube

Now that the rim and tire are clear, it’s time to patch the tube. Select an appropriate sized patch for the hole. Use the sandpaper or scraper provided in your kit to buff the surface of the tube for an area a bit larger than the patch. You need to buff the tube so that it is no longer shiny. If the molding line is running along the area where the patch is to be applied, you must sand it down completely, or it will provide an air channel. Once buffed, avoid touching that area with your fingers.

Apply a dab of rubber cement, and then spread it into a thin coat, using your cleanest finger. Work quickly. You want a thin, smooth coat of cement; if you keep fiddling with it as it begins to dry, you’ll risk making it lumpy. The thinner the cement, the faster it will dry. It is very important to allow the cement to dry completely.

Peel the foil from the patch and press the patch onto the tube firmly, squeezing the patch tightly onto the tube.

Install Tire

Now inflate the tube so it is round and place it evenly into the tire. The first bead of the tire should fit easily onto the rim. Make sure you line up the valve stem with the rim’s valve hole.

Carefully fit the valve through the hole and place the cap on to keep it from falling out again.

The outer bead is harder to install, although most tires can be re-installed by hand. Staring at the valve, work the bead onto the rim using both of your thumbs.

You should never use tools to install the tire, but very tight tires may need some help. Kool Stop makes a great tool called a bead jack, which helps to pull the tire bead over the rim.

Once the tire is seated, inspect the outer edge on both sides to make sure it sits evenly all the way around, and push the valve down into the tire to make sure it didn’t get caught between the tire bead and rim.

Inflate Tire

Inflate the tire to the recommended pressure, which should be written on the side. Make sure to inspect the tire a few times while you are inflating, to make sure the tire remains seated properly and doesn’t start to bulge anywhere.

Once the tire is fully inflated, install the valve cap and put the wheel back on your bike.


Related Links

Discuss this topic in the Tire Forums

11/16 Tubes Bursting on Inner Side

I'm plagued at the moment by tubes which keep bursting on the side closest to the rim. There doesn't seem to be anything obvious which is doing this such as spoke heads sticking out through rim tape, grit, thorns or other stuff stuck to the rim. I inflate tubes to the max recommended pressure (65 psi) and this hasn't happened too often before, so the chances are that the tubes are bad quality (even though they are weighty and not cheap).

I've found that patching holes on the inner side of a tube doesn't work too often because the tube has to stretch and deform as it pushes into t... Read more >>

11/06 Are all folding tyres made of Kevlar bead?

Hello guys

I understand cheaper regular tyres are made with a steel wire bead. But are all folding tyres made of Kevlar bead? I have just purchased a set of tyres as per attached photo and wanted to know if the bead is Kevlar. Can anybody please help?

Thanks...

11/06 Proper procedure for first time inflation

Earlier this year I replaced tires on both vintage bikes, due to dry rot... Age (30+ Years).....

I didn't think anything about the procedure, and did the following on first time inflation (I have an air compressor in garage):

Put about 20 Pounds of air in, then bleed it out.... Then do 30, and bleed...
Then 45, and bleed...... then went to 70....

I used to do the same (at lower pressures) for motorcycles.. I was told this prevents the inner tube from twisting and pinching in the tires.

Is this acceptable for bicycles, too? Or is ther... Read more >>

10/13 Bulge in tire - please help!

My rear tire went flat overnight and when I inflated it in the morning, a bulge formed (see photos). I removed the tire and found a slightly worn spot about the size of a dime on the inside of the tire where the bulge was. I couldn't find any debris in the tire. The tube itself is not worn in that spot.

I remounted the tire twice and the bulge formed in the same place each time. I tried inserting a folded dollar bill, but it didn't help.

The tire is about 2 years old, but hasn't had much use (just occasional city riding). The tube is about a week old.

Ha...

10/04 Slice in tire?

Hey Guys,
Noticed this today... trying to figure out what I ran over to do this?
Can I still ride?...
Anything to do to repair?...
or is it replacement time?

Thanks!...

09/14 Continental Tire and Tube Terminology

The current Continental tire and tube chart has two columns designated ca. and PU. What do these designations mean?... Read more >>

08/27 Please help, Tube sizing problem for my Univega Sport

Hi all,
Please forgive me if this has been covered somewhere on this site, if it has, I can't find it.

I have 26 x 1.50 rims with 26 x 1.75 tires
needed two new inner tubes.

The bike shop sells me a 26 x 1.50/1.75 with Schrader valve and a 26 x 1.9/2.125 also with Schrader valve.
They didn't have anymore of the 1.50/1.75 with Schrader valve and said the 1.9/2.125 would fit especially since it's a mountain/city bike.
The problem is that the 26 x 1.9/2.2.125 is too "big" for the wheel.
The width seems OK but when I put the tube on the rim t... Read more >>

08/06 700c tyres, width advice

Firstly, you are dealing with a dummy here. OK? I have just started cycling again and have 700c x 45 tyres. I'm doing distance charity rides and I'm getting conflicting advice. Some say yes, 45 is fine, a good comfortable ride. Others say, you must be crazy cycling with tyres that wide. They say that the drag, especially on hills, will kill me! Who's right please? Wide or narrow, that is the question?
Supplementary question. If the view is go narrow, do I need new wheels or a new bike? Money is definitely an issue here. I'm not in the big, or even large, budget range.
Thanks[/size&...

07/26 Good Tube keeps going flat

I recently bought a road bike, and on my first ride, the tube on my rear wheel unfortunately got punctured. I used a cement patch kit and the tube seems to inflate well, but whenever i put it back in the wheel and start riding, the tire goes flat again. I'll take the tube out of the wheel again, but the tube seems to work perfectly. Also, when I do inflate the tire and spin the wheel, it is a bit uneven, not side to side, but up and down. My rim and tire seem perfectly fine though. Any suggestions on how to fix the problem, or what's wrong?
Thanks!...

06/29 Tube sizing help for 27" wheels


I've got an old road bike with 27" wheels and 27 1 1/4 (32 x 630) tyres. I just ordered some spare inner tubes online and found out that 700 28-35c should be appropriate for my bike. They have sent me 700 25-28c tubes instead though, claiming that they should still fit, as they cover all tyres from 25-38c (instead of 28, as it says on the label), which is a much broader range than the one they'd originally listed.

I've been trying to find out for quite some time now if these tubes should indeed be fine, so if anyone here has any idea about their suitability that w... Read more >>

06/13 Tube Cracks?

This post may not be clear without pictures, but I'll continue... Smile

Today I rode my bike and my valve stem on my rear tire was crooked. I went to a local gas station that has a free air compressor. I tried to move the tire back into position so the stem would be straight. No go.

I ended up taking the tire off and the tube out and putting the tube back in and re-mounting the tire. When I inflate the tube, I noticed little "cracks" in t... Read more >>

05/31 Went tubeless.

Went tubeless on the Lefty last night. seems to be working and holding air but I have a slight wobble that I don't think was there before. Should I let the air out and try to reseat the tire or what. Seems to be seated ok.

Bill...

05/10 Opening Dunlop (Woods) valve


I'm having trouble inflating the tire on my Dutch bike (I now live in the UK, no longer NL, by the way). It's got what I'm pretty sure is a spring-loaded or one-way Dunlop valve. As you can imagine since the valve is on my desk, the tube is now deflated.

The problem, I think, is that I can't get the valve to open. I'm using a reasonably potent two-cylinder pedal pump, but I can't seem to force air through the valve. When everything is seated properly to pump the tire, if I contort myself to hold the nozzle of the pump as tightly against the adap... Read more >>

04/14 Presta valve broken

While removing the pump head after pumping, the presta valve got broken. I then reinserted the pump to check whether it can sill be pumped, and all of a sudden the remaining needle is lost ( might have gone inside the tube). Is there any way to fix it without changing the whole tube?

And if I need to change the tube, then what would be the tube size? My bike is Giant OCR3 2009 model.

[Image: 20140413_153009.jpg]...

04/05 Presta tubes

When I was younger, I only had a bike till I was25. I am trying to get back into biking again. I bought a vilano performance hybrid roadbike and it came with 700 x 28c tires with presta valves. Now, its been a long time, but what was wrong with schreider valves ? Anyway, I know tubes loose air pressure over time, but I only rode the bike In the parking lot once to see how the adjustments were, one week later, I went to ride the bike, and both tires were completely empty, I pumped them back up to 85 psi, and a week later they were completely empty, I tightened the nuts after and rep... Read more >>

New Thread
How to Fix a Flat Tire
Repair Guide / Help Forums

Free Email Updates: