In this video, we’re going to show you proper use of a patch kit on a bicycle inner tube,
including pre-glued patches, self-vulcanizing patches, and emergency tire boots.
We'll also show you things to watch out for to avoid getting more flats in the future.
Hello, Calvin Jones here with Park Tool Company.
First, let's go over the tools and supplies needed.
You will need tire levers to remove the tire and tube, a pump or method to inflate the tire,
a marker to mark the hole and a patch kit.
The most reliable fix for a punctured inner tube is to simply replace it with a new one.
However, if the hole is smaller than the patch, it may be possible to repair it.
This process begins with the tire and tube already removed from the rim.
If you need help with the removal process, see this video:
If you have a flat, knowing the cause can help prevent future flats,
so always inspect the components: the tire, the inner tube, and the rim.
When possible, reinflate the inner tube to at least twice its normal width and look for leaks.
By over-inflating the tube, you're allowing any small pin-holes in the tube to be detectable.
Listen and feel for air escaping the inflated tube. Be sure to inspect the entire tube.
In some cases, immersing the inflated tube underwater will make the hole easier to find.
If you plan to repair the tube, mark each hole, then deflate the tube.
The type of hole tells us about how the tube was punctured, and helps us prevent another flat.
A small pin hole in the tube may indicate a puncture from a thorn or small wire.
Feel carefully inside the tire body as you look for thorns, pieces of wire, glass or metal.
Remove whatever you find.
If there is something stuck in the tire tread but it has not gone through the casing,
the tire is not compromised. Remove the object from the tread.
A single or pair of short cuts along the side indicate the wheel hit something while riding,
such as a pot hole or rock.
These are called "snake bites", and can also be the result of running too low of air pressure.
A blow out often appears as a large shredded hole.
The tube may have poked out through a rip in the tire casing.
A blowout can also be caused by an improperly seated tire.
With the tube outside the tire, it has no support and it blows out.
This type of blowout looks like a long horizontal slit.
If there's a rip in the tire's casing, the tire should be replaced as soon as possible.
As a temporary fix, you can use the Park Tool TB-2 tire boot.
Peel the backing and apply over the damaged area.
If you have inspected the tube and find no holes, it is possible the leak was at the valve core.
Put some soapy water on the valve and inspect for any bubbles.
Schrader valve cores and removable Presta cores can be tightened
using a valve core remover such as the Park Tool VC-1.
Finally, inspect inside the rim. Look for problems such as holes or failure of the rim strip.
Here the rim strip is damaged at an eyelet, meaning it will not support the inner tube under pressure.
In this wheel, the spoke is a bit too long and is poking into the inner tube.
Once you have located and marked the hole, it is important to clean the area.
One method is to use the sandpaper that comes with the patch kit
to clean by scraping a larger area than the patch you will use.
When possible, wipe the area clean using solvent that doesn't leave a film, such as alcohol.
Allow the area to dry completely.
When using pre-glued patches, such as the Park Tool GP-2,
peel off the adhesive backing and lay the patch squarely over the hole.
Apply pressure to the patch to seal the hole.
The tube is ready to install inside the tire.
Do not test the patch by inflating the inner tube outside of the tire,
as you may stretch the inner tube beyond what the tire body allows.
This pulls on the patch and weakens the bond.
If you are using a vulcanizing patch kit such as the Park Tool VP-1, begin by puncturing the tube of fluid.
Apply a thin coat of fluid.
Use a clean finger or the back of the foil patch to spread the glue evenly around the area of the hole.
Don't be in a hurry to stick on the patch. Allow the fluid to dry – this may take several minutes.
Test by touching the very edge of the fluid.
Peel off the foil backing from the patch, trying not handle the surface.
Apply the patch to the tube, centered on the hole. Apply pressure to the patch, especially around the edges.
Leave the clear plastic cover on the patch – it reduces the friction and rubbing on the new patch.
After a minute or two, inspect the bond of the patch to the tube,
seeing that the edges look adhered to the tube surface.
The tube is ready to be installed in the tire or packed away as a spare for the next ride.
When packing a repaired tube, bleed out the air as you roll it up. This keeps the size to a minimum.
If you need help reinstalling the tube, see this video.
And that's the basic process of how to repair a bicycle inner tube.
Thanks for watching, and be sure to subscribe for the latest videos from Park Tool.