Glasgow MTB. Mad

Fixing a puncture

Can you fix a puncture?
You will be amazed at the amount of cyclists who can’t carry out the old the old basic skill. This is mostly due to the fact that people have never really been shown properly. You gotta say that pushing your bike home is embarrassing, not to mention a major pain in the ar$e. The truth is that fixing a puncture is not that difficult at all. It may seem a bit fiddly the first couple of times, but then you will discover that it’s well….. As easy as riding a bike!

 

Types of puncture

If you have just bounced off a rock or kerb and your tyre deflates rapidly, the chances are that you have a “pinch puncture/snakebite” These are the most difficult to repair as the are generally two slits either side of inner tube. Otherwise the puncture has probably been caused by a thorn, nail, glass etc. These are slightly less obvious to find, but easier to repair.

Avoiding the problem

Glasgow MTB recommends that repairing tubes are best done at home in the dry. Carry a spare inner tube, for all its size and weight. This is a damn site easier that sitting at the side of the trail in the pissing rain messing about with glue and patches. Most punctures are caused by not having enough air in the tyre in the first place. Make sure you check your pressures pre-ride.

Tackling the problem

The first thing to do is remove the wheel from the bike. Put a little air back into the tyre and listen for any air hissing out or bubbles forming on the rubber. Do a visual check of the tyre looking for any thorns etc. sticking out. If there are any objects protruding from the tyre, try to remove them now.

Removing the tyre.

First loosen the little nut on the top of the valve (presta type) and let any remaining air out of the inner tube, this makes the tyre easier to remove. Using your thumbs, push the tyre towards the other side of the rim breaking any bead the tyre has. Now if you are lucky, you will be able to slide the tyre from the rim pretty easily. Unfortunately due to different tyre and rim combinations this is not always achievable by hand. This is where a decent set of tyre levers come in to play.
Prise the lever under the lip of the tyre and lever down using the rim. Now hook the open end of the lever round a spoke (bet you didn’t know what this was for). Use the other lever to get under the tyre a few inches from the first lever, and the tyre should start to pop out nicely from the rim. Usually the tyre will want to come off as soon as you have levered a couple of inches from the rim..
Now completely remove the tyre. Loosen the lock nut and remove inner tube.

Finding the puncture.

Do a visual on the tube, if you have a pinch puncture you will not be long in finding the cuts. If not, put some air in the tyre and listen for hissing or dook in a bucket/puddle and check for air bubbles. Dry the punctured area off and mark with chalk for repairing.
Carefully run your hand round the inside surface of the tyre and feel for any sharp thorns etc. Remove these, as they will only puncture your inner tube again.

Repairing the puncture.

Basically fitting a patch goes like this.

1) Use the sandpaper to rough up the area round about the hole, this helps the patch to stick. Ensure that the area rubbed is larger than the patch. Make sure that you don’t lose sight of the hole.
2) Peel the backing from the patch and stick centrally over the hole ensuring that is not wrinkled and that the edges are pressed firmly down.
3) Hold your thumb over the patch and smooth down for a couple of minutes.
4) Remove the outer plastic cover from the patch from the centre out taking care not to lift the edges.
5) Blow up the tube and check for any leakage. If there is still air coming out, check the patch and for other holes.

Refitting the tyre.

Double check that there are no objects protruding through the inside of the tyre.
Place one edge of the tyre on the rim. Place the inner tube back inside the tyre, place the valve through the hole on the rim and tighten the lock nut just enough to stop the tube sliding back out.
Put a little air in the tube. Just enough for the tube to take a little shape.
Now use your thumbs to seat the tyre back on to the rim. Be patient as this can be a bit of a pain in the ar$e. However slack your tyre may be, you will inevitably come to a point where you can no longer push the tyre on. For this last section, you will again need to use the tyre levers to lever the last couple of inches on to the rim. Do not try to lever too much tyre on at a time. Take care not to pinch the inner tube with the levers.

Blow up the tyres to the desired pressure ensuring that the bead has seated all the way around. Refit wheel and off you go.

Overview

Although these are a long set of instructions, please remember they are only to get you started. As we have said before, once you have fixed a couple of punctures you will not need these instructions.