How to Patch an Inner Tube

01
of 06

Patching an Inner Tube for a Bike Tire

A typical bike tire patch kit with sandpaper, rubber cement and an assortment of patches.
A typical patch kit with sandpaper, rubber cement and patches. (c) David Fiedler, licensed to About.com

If you are cost-conscious, patching your tubes and using them again is a good way to save some bucks, and keep old tubes out of the landfill (though there are plenty of options for recycling and alternative uses for your old tubes if they are wholly unsalvageable).

This patching process is not something you'd typically try to do out on a ride because it can be a bit time consuming. It's much easier in that case to carry a spare tube and a pump or some CO2 cartridges and simply swap out the tube and reinflate. Quickly off you go again which is nice, particularly if you have mates you don't want to keep waiting. 

Patching a tube is something you can do at home so that you can reuse the tube at a later time. Everything you need to patch a tire is available in an inexpensive patch kit that I highly encourage you to keep handy. These usually cost less than $10 but often they contain only a handful of patches however. I've found that once you have tire levers and a scraper, buying patches in bulk - they come in sheets of 25-50 online - and a large bottle of rubber cement available at any craft store is a much more economical way to go.

The following steps assume that you’ve already removed the tube from the tire. If you haven’t done that yet, follow this link to get directions.

Be forewarned that a patched tube will never be as reliable as a new one. The patch can fail again, but the good news is that the defect usually makes itself known immediately.  If you've been riding on a patched tube for any length of time and it's holding air, you're probably good.

02
of 06

Locate the puncture

Find the leak by holding the tube under water.
Find the leak by holding the inflated tube under water. Bubbles will show you the leak. (c) David Fiedler, licensed to About.com

Inflate the tube so that you can find the source of the leak. You can sometimes find the leak by listening for the hissing and following the sound to the hole. A more reliable way is to fill a sink with a couple of inches of water, and then placing a portion of the inflated tube underneath the water, rotating the tire until you’ve watched the entire tube go through. The leak will give itself away by the bubbles it produces when its section of the tube goes underwater. You can circle the spot or mark it with an X using a piece of chalk. Otherwise it can be easy to lose.

Even when you think you’ve found the leak, be sure to still check the entire tube, as there may be more than one puncture. Leaks that occur at the base of a valve stem or along the seam of the tube are usually impossible to repair.

If you are out on the road, you can find the leak by dipping your tube in a creek or puddle. If no other water is available, moisten your fingers with saliva and rub lightly over the surface of the tube until the source of the suspected leak is located.

This is an important step. If you cannot find the leak, you will not be able to repair it.

03
of 06

Prep the site

Prep the site with sandpaper.
Prep the site with sandpaper. (c) David Fiedler, licensed to About.com

Using sandpaper, roughen the area of the tube that is slightly larger than the patch you will use. This allows the rubber cement to adhere to the tube.

Note here the white stuff on the tube is the chalk that was used to mark the location of the hole. It's easy to lose the leak location when moving the tube around to position it to sand and glue on the patch, so that's why marking the puncture site is smart.

04
of 06

Apply rubber cement

Apply rubber cement.
Applying rubber cement. Note that the glue turns cloudy as it dries. (c) David Fiedler, licensed to About.com

Apply a thin layer of rubber cement at the site of the leak over the area you just sanded. Again, this should be slightly larger than the patch you will use. It is not important if you apply rubber cement directly on the hole or not. Allow the rubber cement to dry, a process that should just take a minute. The rubber cement should go from clear to cloudy as this happens. You can hasten this step by blowing on the glue.

05
of 06

Apply the patch

Patch on an inner tube.
Here is the patch on the tube. (c) David Fiedler, licensed to About.com

Most of the time, the patches that come in a pre-made kit will have a thin foil backing which you will need to remove to expose the adhesive. Take that backing off, and apply the patch directly over the hole, pressing it firmly down to seal it onto the rubber cement.

If you do not have a patch, you can try using a piece of another old inner tube cut to the right size if you are really desperate. You will need to use sandpaper to roughen it, since it will not have the same adhesive as the patch from a store-bought kit. It is more difficult to get these patches made from inner tubes to stick and hold, but it will usually be enough to get you home.

06
of 06

Inflate the tube

Inflate the tire.
Inflate the tire to proper pressure shown on side of tire. (c) David Fiedler, licensed to About.com

To inflate the tube, place it into its tire and put the tire back onto the rim.

If you need instructions on this, detailed steps to do that are here.

Inflating the tube on the rim and in the tire is a good idea because it helps seal the rubber cement bond even more thoroughly. The patch gets pressed down and into the rubber cement to give even more security that it will hold.

Though it is impossible to completely avoid getting flat tires, here are some easy steps to greatly reduce the number of punctures that you may get.