Leaking tires aren’t difficult to fix while on the road. All it takes is a little self determination, a comfortable spot to do it, the right tools and materials, and a frame of mind that recognizes this type of repair is long term, but temporary in nature. You’ll need a plug repair kit that comes with an insert tool and fibrous plugs. A reaming tool and rubber cement are also handy, but not necessary.
Here’s how to do it when a nail or similar object is the source of your problem:
Find the foreign object and position the tire so you can get at it comfortably. If you can’t get comfortable access to the spot requiring repair, you can always take the wheel off of the car to work on it. That will allow you to get “right on top of it” for a more comfortable repair.
Estimate the size of the whole you’ll be repairing. A small hole like a nail can be repaired with one fibrous plug while a moderate size hole from a screw or small bolt will likely need two fibrous plugs.
Thread the repair plug(s) into the insert tool until held in the middle of the plug(s).
Coat the plug(s) with rubber cement. (optional step)
Pull out the foreign object with a pair of pliers.
Ream the hole so the plug will insert easily. (optional step)
Insert the fibrous plug(s) using the insert tool. The plug will fold up as you push it into the tire. Push the tool into the tire until the loose ends of the plug(s) are just above the surface of the hole.
Twist the insert tool a couple of times to wad up the plug on the inside of the tire.
Withdraw the insert tool until it just clears the surface of the tire as it pulls the folded over portion of the fibrous plug(s) back out through the hole, effectively doubling up the fibrous material to fill up the damage done by the foreign object.
Cut off the plug(s) as close to the surface of the tire as you can.
Fixing a hole in a tire will require considerable effort. It’s best to practice on an old tire first to see just how much force you’ll have to exert to get the insert and reaming tools to penetrate the tire.
Also, if you intend to fix the leak with the wheel on the vehicle, you need to be quick from the time you remove the foreign object to the time you pull the folded over end of the plug back out through the tire. It is possible to do this quickly and still keep plenty of air in the tire so you can continue on your way.
If you find yourself needing to take the wheel off to get good access to the spot requiring repair, it’s just as easy to install the spare instead of trying to fix the tire. Of course, you always carry a properly inflated spare with you, right?
Leaking tires caused by cuts or large holes, or damage to the sidewall cannot be fixed in this manner and will require taking the tire off the wheel for repair or replacement. Also, if the repair is in the edge of the tread adjacent to the sidewall, expect that the repair won’t hold well for very long.
In any event, it’s recommended that you get the tire dismounted and repaired from the inside at the next opportunity as fibrous plug repairs can be permanent, but many of them will perform as if they know they’re only temporary in nature.