Bike restorations go hand in hand with flat tires. If you’re anything like me, you go to the extreme in being able to fix any inner tube, no matter how much the damage. Because unless the inner tube actually crumbles while looking at it, it’ll always be more expensive to replace it than to fix it. So in this ultimate guide you’ll learn all you’ll ever need to know about how to fix flat bike tires.
Video Tutorial
If you don’t like the video or need more instructions, then continue reading.
Bike tire punctures vs. bike tire blowouts vs. slashed tires
There are three type of repairs out there:
- Punctures: sustained by riding over a sharp object in the road (probably). This usually leads to a hole the size of a pin.
- Blowouts: sustained because of a tear in the tire causing the inner tube to push through and blow. This leads to a much larger hole with tears in multiple directions. Sometimes shaped like a star.
- Slashes: Driving a sharp object like a knife or screwdriver through the tire on purpose. The damage is based on the object that does the puncture. A knife will lead to an elongated cut of varying length. A screwdriver obviously is very different.
I’ve dealt with all three sorts of punctures, and have successfully fixed them as well. Punctures are the easiest to fix. Blowouts are the most difficult. The latter can be very large. But all of them can be saved.
Step 1: Removing the wheel makes it easier to fix flat bike tires
When you fix flat bike tires is easiest when you’re able to remove the wheel. If you don’t have wheels with quick releases this might not When you fix flat bike tires it is easiest when you’re able to remove the wheel. If you don’t have wheels with quick releases this might not be an option. an option.
If you remove the wheel from a bike with a quick release it probably also has a derailleur. Shifting to the lowest gear you have makes getting the wheel out easier.
Don’t put your bike on the handlebars if they’ll be resting on the shifters, since that may damage them. Lay the bike sideways on the non-drive side . And do so in the grass not on the pavement.
Make sure to check the tire and see if the cause of the puncture is still there. There’s little use in repairing a flat tire and putting it back to only have it being flat immediately again.
Step 2: Removing the inner tube
Now it’s time to remove the inner tube. There are two types of tire lifters to pop the tire from the rim so you can reach the punctured or busted inner tube. Metal or plastic. Always use the plastic (black) tire lifters! Some outer tires need a lot of force between the edge of the rim and the tire bead. Using aluminum tire lifters can easily cause damage in these cases.
Start inserting the tire lifter somewhere on the tire away from the valve. Especially on slim rims the space between the rim and the valve is small. Also insert at the side of the rim where a spoke goes into the rim. This makes it more easy to grab the spoke with the hook at one end of the tire lifter
Since the valve is a metal piece inserted into the rubber of the inner tube, it’s the weakest part of the tube and should be handled with care. Removing the outer tire at exactly this place is a bad practice.
Tire lifters come in pairs (or trios). With one lifter in place and grabbing a spoke, insert the other next to the first one and work it alongside the rim, popping the tire bead. If the tire bead sits too tightly behind the rim, pop several areas in close proximity of the fixed lifter before sliding it.
With one half of the outer tire freed, you can remove the inner tube. Start with the valve. As soon as the valve is free from the rim, getting the rest of the inner tube out is a piece of cake.
Step 3: Finding the puncture
You don’t need a bucket of water to find a tire puncture. It’ll only make a mess of things. Simply put a considerate amount of air into the tube. You’ll either find the puncture through sound or feel.
If you really have a hard time finding the puncture, move your head close to the tube or move your hand and fingers alongside the rubber. This’ll make it easier to detect through sound or feel.
When you’ve found the puncture, mark it with a ballpoint, this will make your life easier later on.
Step 4: Patching the inner tube
With the inner tube freed from the rim, the next step in to fix flat bike tires is patching it. Through the years I’ve used many different brands and many different versions. I find the type of patches you have to cut yourself to be far superior to the sun-shaped ready-made ones.
The ones from the Dutch brand Simson are pretty iconic. I’ve used them my entire life and see no reason ever to use anything else. You can patch two dozen times from one kit for a couple of bucks. The same goes for their solution medium, which is the specific glue that bonds the rubber of the inner tube with the patch through the process of cold vulcanization.
Before you patch the puncture, you can opt to sand the area around the puncture first. This will improve the adhesion of the patch to the tube. I have to admit that for the longest time, I had no idea what sandpaper was doing in my bike repair kit. So I’m kind of used to skipping this step.
When I know where the puncture is and I have the patch ready, it’s time to apply the solution medium or glue. First I make a circle evenly around the puncture before applying glue to the entire area where the patch will go. As soon as glue is on top of a small puncture there’s no way you can see it. And you want the puncture to be in the exact middle of the patch to improve its durability.
And make sure that the area with glue is greater than the patch. Once it goes on you don’t want to have to put extra glue underneath the patch where there is none. This might easily ruin your attempts to fix flat bike tires.
Before applying the patch let the solution air dry for about 2 minutes (or less). Using a timer (on your smartphone) makes this easy to remember. As the solution dries it becomes dull. When it has dried appropriately you can apply the patch. You don’t need a ton of pressure.
Make sure you don’t touch the solution that sticks out from under the patch. It’ll stick to your fingers and you can rip both the solution and the patch from the tube before it has a chance to set.
By applying an extra layer of solution on the edge of the patch, you improve the adhesion in its weakest area. You can simply let the solution sit on the edge and air dry as well.
For ages I thought the patch needed to dry for a long time. But, when done correctly, five minutes should be enough.
Step 5: Installing inner tube
Now the inner tube is patched, it’s time to install it. You need to keep just enough air in the tube so that it’s not entirely flat. This will aid in the tube having its correct shape in the tire and not getting twisted or squashed.
Start by inserting the part with the valve first. It’s both the weakest point of the tube and hardest to get in.
Then get the rest of the tube in by working your way from the opposite side of the valve. This ensures the tube gets in evenly, instead of being bunched up in one place. When inflated, even slightly, the inner tube’s diameter is often much larger than the tire.
Step 6: Installing outer tire
When installing the outer tire, start with the valve. By pressing the valve back into the rim there’s more space for the tire bead, making it easier to get the bead over the rim. If the tire bead is over the rim at the place where the valve is, work your way on either side of the tire, pressing it over the rim.
Make sure the valve is aligned with the spokes on either side. If it isn’t an inflated tube puts more stress on this weak area, which might compromise it in the long run.
Sometimes the last part of the tire can be really tight on the rim. You can use a tire lifter to get this last part in.
You’re now ready to inflate the tire.
Congratulations, you now know how to fix flat bike tires.
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