How to repair a puncture

From TrialsWiki

Repairing a puncture is a fairly simple but time consuming procedure. Punctures are a common occurrence in Trials, the most likely way you will get a puncture is known as a 'pinch flat' or a 'snake bite'. This is where you may land on the corner of an object and the tire will be compressed against the rim causing the inner tube to be pinched between the sidewall and the tyre, a pinch flat can be easily diagnosed as the inner tube tends to deflate quickly as there are two holes in the tube caused by pinching of the two sidewalls. In this section we will look at how a puncture can be repaired and the procedures that should be taken to complete a long lasting repair.

Contents 1 Diagnosing a puncture 2 Tools Needed 3 Method 4 Self Adhesive Patches

[edit] Diagnosing a puncture

A puncture is obviously very easy to diagnose, your tire is flat and as you pump it up the pressure is not increasing. The not so easy part is finding where the puncture is actually situated on the inner tube, there are two methods for locating the puncture.

1. Pump up the inner tube as fast as you can and then listen for air escaping, on smaller punctures you may need to run the inner tube past your ear.
2. This is the quicker method for finding the puncture, pump the tube up and submerge the whole tube into water, you should then notice air escaping from the puncture. ( This will be in the form off bubbles, once found you must dry the inner tube off before carrying out the repair otherwise the rubber adhesive will become diluted)

[edit] Tools Needed

1. Pump
2. Puncture repair kit
3. Tyre Levers

The first step to repairing your puncture is to remove the tire, this can be quite a difficult job as tire beading can be quite tight around the rim making it very hard to lever the tire off. You need to wedge a tire lever under the beading and lift it over the rim so you can gain access to the tube inside, it will be easier to use more than 2 tire levers. Once the tire is off you can then pull the tube out, removing the wheel from the bike before hand is of no real benefit unless you need to use the water method above. It may be easier to leave the wheel in the bike and turn the bike upside down so it supports itself. Once the tube is out of the tire you can then begin to pump the tube up and locate the puncture.

To make it easier to get the tyre of the rim make sure that you push the edge of the tyre into the middle of the rim all way around then you should be able to pull it of with only one tyre lever. Stick it in, bend it up, hold it from the backside with your thumb and just drag the tyre lever along the edge of the rim.

[edit] Method

1. Mark the puncture with a crayon
2. Rub the area with sand paper from the repair kit to scuff the rubber
3. Making sure the tube is fully deflated* apply the rubber adhesive sparingly. *(the tube should be fully deflated otherwise you will get air escaping while the rubber adhesive is drying)
4. Peel off the backing from one of the patches and wait until the rubber adhesive goes tacky
5. Once the adhesive has gone tacky (not shiney) you can then apply the patch
6. Apply firm pressure onto the patch making sure there are no bubbles under neath
7. Apply pressure until you are quite sure the rubber adhesive has set
8. Place the inner tube back into the tire and put the tire back on
9. Pump the inner tube up once its inside (as the tube inflates the patch will be pushed against the tire stopping it from peeling off)

[edit] Self Adhesive Patches

Self adhesive patches are becoming quite popular, they are same as a normal rubber patch but instead they have the rubber adhesive already applied to the rear of the patch, this means that you don't have to wait for the glue to go tacky before applying the patch to your puncture. Other than saving time they are not worth the extra money you pay, they can be quite useful if you are on a group ride and you want to fix your puncture quickly. The same procedures apply when using self adhesive patches, the affected area must be clean but you can insert your tube straight back into the tire without waiting for any adhesives to dry.

• Two popular self adhesive patch's are 'Skabs' produced by Slime and Park Tools self adhesive patches, from experience I've found the Park Tools to be slightly better as they make better contact with the inner tube, giving less of a chance of that the patch will peel away.