How to Patch a Bike Tube Properly

A patched tube gets a bad reputation it does not deserve. Done properly, a vulcanising patch fuses to the tube and is as strong as the surrounding rubber — the tube will fail somewhere else long before the patch lets go. Done impatiently, it peels off within a mile, which is where the reputation comes from. The difference is almost entirely about waiting for the cement to dry.

Finding the hole

Inflate the tube to roughly double its normal riding shape — fat, not hard. Then work through these in order of speed:

1. 01Listen. Hold the tube close to your ear and rotate it slowly. A fresh puncture is usually audible.
2. 02Feel. Pass the tube slowly past your cheek or the back of your wet hand. Moving air is easier to feel than hear.
3. 03Water. Submerge sections in a bowl or bucket and look for a stream of bubbles. This finds anything.

While you have the tube out, note where the hole sits relative to the tire and check that spot on the casing. Our guide to fixing a flat bike tire explains what each hole position tells you about the cause.

Applying a vulcanising patch

The full sequence

1. 1

   Deflate and dry the tube

   Let the air out so the rubber is not stretched, and dry it completely if you used the water method.

2. 2

   Scuff the area

   Use the sandpaper or metal scuffer in the kit. Abrade an area noticeably larger than the patch until the shine is gone and the surface is uniformly dull. Do not touch it afterwards — skin oil undoes this.

3. 3

   Spread a thin layer of cement

   Squeeze a small blob on and spread it with a clean finger over an area larger than the patch. Thin and even, not a puddle.

4. 4

   Wait until it is touch-dry

   Three to five minutes, longer in cold or damp conditions. It should look matt rather than glossy and feel tacky rather than wet. This is the step everyone rushes.

5. 5

   Peel and press

   Peel the foil from the patch without touching the adhesive face. Place it centrally over the hole and press hard from the middle outwards for a full minute to drive out any trapped air.

6. 6

   Leave the backing on

   The clear plastic film on top can stay. It will split naturally when the tube is inflated inside the tire. Peeling it can lift the patch edge.

Glueless patches

Glueless patches are pressure-sensitive adhesive discs. They need the same scuffing but no cement and no waiting, which makes them excellent for a cold roadside. They do not vulcanise — they stick. Over months, heat cycling and pressure will eventually work them loose.

When not to patch

• A tear at the base of the valve. There is no flat surface to bond to and the stress there is high.
• A split longer than roughly 6 mm, or any hole a standard patch cannot cover with a wide margin.
• Two holes very close together — a pinch flat. You can patch it, but a single patch spanning both is under more strain.
• A tube already carrying several patches, or one where the rubber has gone hard and shiny with age.
• Any hole on a latex or TPU tube unless the kit specifically says it supports that material. Standard cement does not bond well to either.

Once the patch is on, refit the tube using the sequence in our guide to changing a bike inner tube — slightly inflated, valve square, thumbs not levers.