On “Internal Flat Tires” and Rim Tape Substitutes

From Rookie’s Keyboard

Hello, friends

I decided to dedicate my weekend topic to a slightly unpopular biking issue known as “internal flat tires”. 

What does this even mean?

Normally, flats are caused by a sharp object piercing the tire and the inner tube.

What if I tell you that flat tires could also be an inside job?

In other words, sometimes they will happen without an external object.  One of the sources of this unpleasant problem would be the lack of adequate rim tape separating the wheel’s rim from the inner tube. 

This area should be covered to avoid “internal flats”.

Sometimes the rim tape is worn or out of position. And when that happens a spoke or a spoke hole can pierce the inner tube from the inside. 

And when you check the tire and the inner tube for external objects, you won’t find anything. If you’re a noob, you may conclude that “it’s all good”, then change or patch the tube and ride away only to experience a flat 20 minutes later. 

The ideal fix is to replace the rim tape. You need one that matches the inner width of the rim. 

In a pinch, you can also use electrical tape. 

However, electrical tape(ET) isn’t ideal for the job of rim tape in the long run for the following reasons: 

  • ET can’t sustain high-air pressure

Electrical tape is quite soft and prone to elongation. If you have road or even hybrid tires and pump them to the air pressure they need, the inner tube will easily push through the electric tape. 

It can then come in contact with the threaded end of a spoke or a sharp edge of the spoke eyelet/hole.

Don’t forget that spoke eyelets are never smooth and spokes’ ends are always sharp. Any contact with them can cause an internal flat tire.

Of course, if you have MTB tires operating at low PSI, electrical tape has a much greater chance of holding up. But even then, real rim tape is better because it’s much thicker and less flexible than electrical tape and thus greatly reduces the possibility of flats caused by the rim and spokes.

  • Subpar Resistance to High Temperatures

If you have rim brakes, the rims can easily reach epic temperatures on descents due to the friction between them and the brake shoes. Of course, if it’s a sunny day outside, the effect will be even greater.

Heat will quickly melt the electrical tape’s adhesive. As a result, the tape will move out of place and fail to do its job. Not to mention that the melted residue will contaminate the rim.

If you have disc brakes, the issue is not nearly as extreme as the rotor would be the overheating unit. One more reason why ET is more suitable for MTBs.

Duct Tape Is Simply Better

Nothing beats standard rim tape. But duct tape is definitely better than electrical.

Duct tape is less stretchy, stronger, and has better adhesion. However, it’s also wide, and you will have to cut it/rip it into thinner pieces. 

Luckily, I know a trick that will make that process super fast and surprisingly accurate. 

1. Mark the inner rim width on the duct tape.

2. Take a sharp utility knife (or a chisel if you have one) and elevate it to the mark by putting a small book under it. Press the knife against the mark firmly.

  1. Hold the position of the knife while rotating the roll. Keep doing it until you have a long enough piece.

Keep in mind that quality duct tape is more expensive than average rim tape and leaves a nasty sticky residue on the rim. 

You can also use:

  • 3M Reinforced Strapping Tape (Consider applying two layers for additional strength.)
  •  White Medical Tape
  • Hockey Tape(The type of tape that hockey players use to protect the blade of their stick and improve its friction against the disk.)
  • An inner tube

It’s also possible to make rim tapes from old inner tubes.

1. Cut a piece of inner tube as wide as the internal part of the rim. The inner tube should be long enough to cover the rim and then some. Keep in mind that it can stretch a lot too.

  1. Sand one end of the inner tube and put rubber cement on it (the chemical used to glue tire patches.) Wait for 4-6 minutes for the cement to penetrate the tube.

3. Wrap the inner tube around the rim, overlap the ends, and press them against each other. Hold the position for a minute or two until the glue sets.

4. Use a paper punch to make a hole for the valve on the overlapping (double) part.

Do not use another area for the valve because the hole will thin out the inner tube too much. The overlapping section is simply ideal for a valve hole.

This method works as a fix but has its shortcomings. Inner tubes are very flexible, and if the tire pressure is high, an internal flat can technically happen as the original innertube might get into a spoke hole. It’s unlikely, though.

For extra safety, you can consider putting a top layer of electrical tape.

And there you have it, friends. Another post that should make the cycling life of a rookie a little easier. 

I am about to go to sleep now as tomorrow is another day at the office. It is what it is.

Until next time,

– Rookie







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