Patching a punctured bicycle tyre tube

Patching a punctured bicycle tyre tube

Updated: 16/11/2018.

This post explains how to patch a bicycle tube. If needed, read posts on how to remove wheels and how to take tyres off and tubes out. Finally, here’s a post explaining mounting tyres and tubes onto a rim.

1. Inflate (removed) tube to see where the puncture is

If a puncture can’t be located visually – very small leaks that can’t be heard, or felt with fingers, try using water:

Placing a tube in a bucket with still water, bubbles will appear in a place where the puncture is.
Placing a tube in a bucket with still water, bubbles will appear in a place where the puncture is.

Place (or several places) where the puncture is found should be marked:

Marking the puncture location.
Marking the puncture location.

2. Determining the cause of puncture(s)

Before patching a tube, a cause of flat should be determined and fixed.

a) Snakebite

If a tube has two parallel holes (cuts) at a small distance, then it is a pinch flat, also called a snakebite. It happens when a tyre is not inflated enough. When a wheel hits a bump, the tube gets pinched against the rim and gets cut.

Snakebite
Snakebite

b) Rim/spoke damage

If there is a hole on the inner part of the tube, the one towards the rim, then rim needs to be checked for sharp objects, or sharp parts of a damaged rim. Also, rim tape needs to be checked – is it undamaged, is it placed correctly. In case of double walled rims, make sure the rim tape is a good quality high pressure one. All explained in this article:
Rim tape types.

If a cut is near the valve, the tube can not be patched.

Tube cut near the valve. Such tube can not be patched.
Tube cut near the valve. Such tube can not be patched.

c) Hole in the outer, or side part of the tube

Probably from some sharp object – thorn, or glass. Carefully examine the outer tyre, make sure the sharp object is not still in the tyre – to cause another puncture. Turn the outer tyre inside out and examine carefully. Slide some fabric along the inside of the tyre, or fingers, but be careful not to cut your hands.

D) Long cut in the tube

If a tube has a large cut, or a blowout like a balloon , then it can not be patched.

Blown tube
Blown tube

This can be caused by poor tube quality, but more often it is due to outer tyre casing failure, or improper mounting of tyre and/or tube. This can also happen if rims overheat from long braking (if rim brakes are used). Pressure rises with great heat, outer tube gets off the rim from over inflation of the tube and then tube bursts.

Tyre wall cut
Tyre wall cut

If a tyre wall is cut like in the picture above, tube often explodes. This is caused either by poor tyre quality, or by a large sharp rock.

Tyre can be patched to get home, but needs replacing as soon as possible.

Patching cut tyre
Patching cut tyre

Tyre can be patched either with special tyre patches, or with a piece of hard card board, or with a dollar bill, or a part cut from another (old) tyre, but not the tube! Do not use a piece of tube to patch cut tyre, since it is not firm enough to hold pressure.

Affiliate link of an Amazon.com search for the (as an Amazon Associate I earn from qualifying purchases): Special tyre patch boot (Park Tool TB-2 emergency tyre boot). It is a good “first aid” patch, enabling one to get home and replace the cut tyre. It is not a permanent(ly safe) solution!

Park Tool TB-2 - temporary, emergency tyre boot (patch)
Park Tool TB-2 – temporary, emergency tyre boot (patch)

3. Patching a tube

First tube needs to be treated with sand paper around the hole. Place where a patch is glued needs to be totally flat, dry, clean. Especially if it is near a tube seam.

Šmirglanje pre lepljenja
Sand paper scrubbing before patching

Then add patching glue. Use the cleanest finger to nicely and evenly spread the glue.

Spreading glue on the tube
Spreading glue on the tube

Wait five minutes for glue to dry.

Place a patch. Press firmly, to make sure no air is left trapped.

Placing a tube patch
Placing a tube patch

It is best to leave the patched tube to dry completely over night. That is why it is wise to carry a spare tube. Patched tube is packed in a bag, while the spare one is used to continue riding. This way, the same three tubes can be rotated for decades. 🙂

 

Author’s recommendation for tube patching are Rema (“Tip-Top”) glue and patches. Click on the image below to shop on-line at Amazon.com (as an Amazon Associate I earn from qualifying purchases):

Rema bicycle tube patch kit
Rema bicycle tube patch kit

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