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Fixing a Flat Tire

There are two basic version of this. Carry a cell phone, a credit card and some form of emergency road side assistance program. The second type of fix includes buying and have on board the bike everything you need. And know how to use what you do buy before you have a flat on the road. This article will address the latter. The most important part of this is to know how to use what you buy BEFORE you have a flat on the road.

Generally the kits you purchase will have some instructions with them. The goal here is not to replace those instructions, but supplement them with some tips and tricks from your fellow COG members.

Tire Repair Kit:
The contents of your tire repair kit may include the following. There are kits available from your local auto parts store and motorcycle dealers that come in a variety of contents and prices. At minimum you'll get a set of repair strings/plugs and the reaming and insertion tools. Other kits can include everything you see here complete with CO2 cartridges for inflating your tire.

  • 1 or more methods to inflate your tire.
  • Tire repair strings and plugs ( included in kit )
  • Tire Reamer Tool ( included in kit )
  • String/ Plug Insertion Tool ( included in kit )
  • Rubber Cement
  • A set of small side cutting pliers
  • A valve stem core removal tool
  • Spare valve stem core
  • Spare valve stem cap

First note on the insertion and reaming tool is to get a nice T-handle one. A really stout grip is essential to ease of use. Any tools that are like screwdriver handles will leave you frustrated and unhappy in the end... probably WAY before the end.

COG member Rev Rider reports "Red Camel Brand" string/plugs. These are the best I have ever used and they work sans glue with nary a failure of any kind on any tire I've ever plugged that wasn't REALLY destroyed."

Most Common Mistake:
The main mistake many make is not reaming the hole out enough.  They are afraid it will cause the plug to come out.  Truth is the sharp ends of the steel belt if not reamed out good will cut the plug and cause it to fail.
Get off the road as safely and as far as you can to put you in a "PRIVATE" an area as you can. If that's a convenience store parking lot or a gravel shoulder, it is what it is and you'll have to make do. Next you really need to be able to put the bike onto the centerstand if at all possible. This will make the rest of the job easier. Once up, the rear is easily rotated to inspect for the intruding material that has vented your precious air from inside your tire. The front tire will be a bit more difficult unless you can block the bike up while on the centerstand to lift it off the ground. In any case, even if you have to just roll the bike forward or backward to look for a nail, etc. in your tire, that is what you will be doing. Once you find the offending object, your ready to whip out the trusty box of goodies.

Repairing the Flat:
Follow the instructions for the tire repair kit you have purchased. Note the use of any rubber cement and any drying times, etc. Here are some additional tips and tricks.

When you first grab your side cutters and begin trying to get a grip on the nail/object to pull it out of the tire, as you pull it out watch to see which way it went in.  If it is at an angle you will want to follow the same route with your other tools and your plugging material.

Once the nail hole is mentally mapped out, pull the nail all the way out and insert the reaming tool into the same hole at the same angle the nail was removed.  This way you will not be creating an entirely NEW leak, but actually repairing the existing one. Insert the reamer and then twist it around and slide it in and out a bit as well to clean and open the wound to accept the new rubber piece.

When you are confident that the hole is sufficiently cleaned and opened, insert a tire repair string plug into the insertion tool so that the tool point is midway on the string and then in one swift and powerful motion, push the entire unit into the tire to the hilt of the insertion tool. This is easiest to do if there is still some air pressure in the tire. However, that may be difficult to do if the tire was completely flat already. Once the tool is completely embedded into the tire, remove the insertion tool which will leave the plug installed in the hole.

Inflating the tire:
Click on this link to read our Tire Inflation Tech Page for the pros and cons of the various methods of inflating your tire.

When you are ready to completely inflate the tire, inflate the tire then trim the excess plug material from the outside with the side cutters. Check the tire for any other leaks including around the plug you just put in. Spraying a little water or liquid around the plug and check for bubbles. When you are certain that the tire is no longer leaking, you are ready to go. Whenever you stop for gas or to rest take a look to make sure the plug is remaining secure.

Will the repair last:
COG Tech Editor Fred Harmon reports, I used to use the sticky rope plugs only as a temporary repair, and when I got home, I would remove the tire and put a T patch on it from the inside, as that seems to provide a more solid repair. However, in recent years, I have stopped doing that after finding that the sticky rope plugs seem to last the life of the tire and usually provide a very solid and long lasting repair. Occasionally I will find one that begins to "slow leak" after a few thousand miles though. I have never had, nor ever heard of, a sticky rope plug "blowing out" of a tire. They can't due to the way they vulcanize to the rubber. I've tried to actually pull them out with pliers after taking the tire off the rim, and they are virtually impossible to remove, as they become one with the tire in just a few hundred miles.
Things to remember:
Many of the string type tire repair kits contain rubber cement. This can dry out over time. Especially in the heat from the engine, under the seat where many riders keep their kits. Check your kit once or twice a year and replace your old dried out cement. Don't find out the hard way, when you really need it.
What about small holes:
For smaller diameter holes, the dyna plug tool is an option. ( ). The advantage of the Dyna plug is that they are very small in diameter and the tool is very small, so it offers a repair that is minimally invasive on the tire carcass and doesn't stretch out the hole any larger than it already is. They also don't require glue, which can be a problem on standard string kits if the glue in the container has all dried up.
What to avoid:
Whatever you use, it is highly advise AGAINST using the mushroom type plugs. The insertion tool will stretch out the hole so large that it will destroy the tire for any future repair. The mushroom plugs will also leak, they don't vulcanize, and many times the heads of them will shear off. Its been reported that had one plug come totally out of a tire.
What about speed:
Anytime you ride on a plugged tire, you should never travel at higher speeds. It is advised not going over 80mph on any tire that has been repaired, and even this is pushing it a bit.
Here is a really nice photo sequence of a tire repair by COG Tech Editor Fred Harmon.
Interesting note from the geek typing this up. Fred is also using the red Camel Brand repair strings that Rev Rider mentions above. Hmmm.... I think I am going to go and get me some of them.

The Tire Kit

Notice how the nail is removed at the same angle it went in at.

Inserting a string onto the insertion tool

Apply glue to the string

A little glue on the tire too

Reamer is done at the same angle as the nail went in

Plug is inserted at the same angle too

With the tool remove it should look about like this

Trimming the excess

After several hundred miles of riding

Article By: Rev Ryder & the COG Forum

May 2011

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