Author: Anthony Robson

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Tuesday, April 29th, 2008 at 10:58 am
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How To Mend a Puncture

If there’s one maintenance skill that you’ll be glad you learned with your bike it’s how to fix a puncture. While some squidgy brakes or a rattling chain will normally last until you’re home, the chances are that sometime in your cycling life you’ll be stranded in the middle of nowhere (or at least a few miles from home) with a (pun warning) rather deflated feeling and absolutely no way of being able to ride any further.

At this point a small puncture repair kit and mini-pump will seem the best investment you ever made. It’s also one ‘skill’ that a lot of people don’t really have, so here’s an easy 5 step plan to getting you on the road again.

1. Remove the Wheel

Okay, seems a bit obvious, but it is possible to fix a puncture with the wheel still on the bike, but when it comes to forcing the tyre off and on the rim the job is far easier without the frame getting in the way. Most modern wheels will be quick release making it easy simply to flip the lever to remove the wheel, but old nutted wheels or allen key fixings will mean you should also carry a spanner or set of allen keys. If you have disk brakes just life the wheel away; with calipers there is a little lever to the side which widens the gap; cantilever brakes (below) need the straddle wire disconnecting Caliper Brake

v-brakes (below) need the ‘noodle’ taken out of its cradle to release the pads to the side.
V brake

2. Remove the Tyre

The ease or difficulty of doing this is determined entirely by how tight the tyre is on the rim, but the basic principle is the same. Firstly deflate the inner tube. Schraeder valves (car type) just need the centre of the valve depressing; with presta valves (on road bikes) the central part unscrews upwards (not all the way off) and then depresses. Then, with a tyre lever (or spoon with large flat-ended handle – that’s what I learned with!) lift off the tyre on one side.

Tyre Levers 2a Tyre Levers 2b
You can then try and break your fingers by fitting in a second tyre lever and pushing it round the rim to unseat the tyre. It should get easier the further round you get, until the whole of one side of the tyre is hanging off the rim and the inner tube can be pulled out (after pushing the valve through its hole).

3. Find the Puncture

There are two very simple ways to find the puncture, and both need a bit of air pumping into the tube first. The hole might make itself obvious at this point, the hissing allowing you to pinpoint exactly where it is. Running the tube past your hand or face you might feel the escaping air.BubblesSmaller holes might not be quite so clear, and for this a convenient bucket filled with water will do the job (although obviously if you’re stuck in the middle of nowhere this might be harder to procure). Pop the tube under the water and spin it round – the puncture will make itself known with a stream of bubbles.

At this point you need to get your puncture repair kit and take the crayon out (trust me, there will be one) and mark the location of the puncture.

4. Repair the Puncture

This couldn’t be easier. Every puncture repair kit will contain the essentials, being: the aforementioned crayon; a bit of chalk; some glue (vulcanising rubber solution); some sandpaper; and the patches.

Repair KitTake the sandpaper and roughen the area of the hole; this will give the glue a better surface to stick to. Then apply the glue in a thin layer, spreading out with your finger to an area slightly larger than the patch you have chosen, and leave that to air dry for about 30 seconds or so. Then pick out your patch and hold it in place for another 30 seconds at least (I tend to hold it down with my thumb pressed into two fingers placed underneath the tube). Get the chalk and with either the sandpaper or rough area on the box (trust me, there will be one) sprinkle some chalk dust around the area, which will stop the exposed glue from sticking to the inside of your tyre later on.

5. Reassemble

Basically the reverse of the above process. But before you do anything CHECK INSIDE THE TYRE! There is nothing more depressing than going to all of this trouble, then hearing that telltale hiss as you pump the tyre up. Whatever caused the puncture might still be inside the tyre, so go around it (inside and out) to see if anything is poking through.

Tyre Levers 1aPlace the valve through its hole in the rim and put the inner tube inside the tyre. You can then start tucking the tyre back inside the rim, first with your fingers (which some with fingers of steel can manage for the whole tyre) and then with the tyre levers running round the rim. Towards the end it will get a hell of a lot tighter and no amount of swearing will generally make it budge. At this point I make the levers earn their name and force the tyre back into the rim.
Before putting the reassembled wheel back onto the bike, quickly pump up the tyre to make sure the repair is holding – and then put the wheel back on the bike (remembering to reattach the brakes if you had to separate them) and that’s it. Simple as that.

Happy cycling!

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