Between Monday Maintenance and our Scoop’s Scooter build up features we’ve covered most maintenance and mechanical issues that can be easily sorted in the home workshop. However the summer months bring out a whole new set of cyclists who nobody has even shown how to do the most basic bike maintenance.
Maybe the bike shop owner just popped out the front wheel, stuffed the bike in the boot and waved a cheery goodbye. Perhaps riding partners always sort out the grinding noises and punctures that occasionally appear. Well the trouble is, you’re then – through no fault of your own – totally reliant on other people in even the simplest to solve situations.
So for all those people who just get given things to hold, get tutted at, or have their biking trip ruined when they have to walk home with a punctured tyre, it’s time to overcome your fear and master the basic skills you need to keep on rolling. Sheesh, you might even enjoy it!
This week – that classic cycle repair – fixing a puncture.
(Anyone chuckling at the back can clear off right now and go and do something useful with their spannering supremacy like helping out on the Maintenance section of the forum.)
What a let down
Often the biggest pain with punctures is finding out where they are and what caused them. Before you pull the tyre and tube apart, try pumping them up and listening where the air is coming out from. Look for thorns in the tyre from the outside or – if the tyre is wet – look for bubbles blowing through from the inside. Air can seep out anywhere round the tyre but this generally gives you some idea roughly where it is.
If you find the hole mark it on the tyre or rim with chalky rock or something tied round a spoke and then take your wheels out of the bike.
The first thing to do is create as much slack as possible around the edge of the tyre and the rim. Press the pointy bit of the valve (on pointy Presta valves you’ll ha e to loosen the little knurled collar slightly first) down to release any air that’s still trapped in the innertube.
Now grab the tyre and pull it inwards away from the edge of the wheel rim, working all the way round until it’s waggling about on the wheel. This loosens the tyre and gives you more slack, making it easier to pull it off.
Now take the edge of the tyre and pull it up to the rim. Different tyre and rim combinations have different levels of slack, and if it’s really loose you may be able to push the lip of the tyre over the rim with your thumbs.
Otherwise you’ll have to slide tyre levers (use two side by side) under the tyre edge and lever it off with them. Once you’ve got the levers in and the tyre is stretched over the outside of the rim, hook the hook end of one lever round a spoke, and work round the edge of the tyre with the other until the tyre gets loose enough to be pulled off with your fingers.
Now undo the lockring on the valve and push back through the rim before pulling the innertube out of the tyre.
What sort of puncture?
If you’re wheel went flat very quickly after hitting a big rock or kerb then chances are you’ve pinch flatted. This means the innertube was squashed between the rim and the rock and probably split on both sides. You’ll have two splits on either side of the innertube (which is why these punctures are also called “Snakebites”) which are really hard to fix with repair patches. On the other hand you’ll know you don’t have to spend ages looking for a thorn – although it’s always worth a quick check just in case.
If it wasn’t a pinch flat then check the inside of the tyre thoroughly to see if the thorn, nail, glass or whatever is still there, otherwise you’ll just puncture again as soon as you put the tube back. Try inflating the tube to see where the air hisses out and then – using the valve as a reference point see if that points to where the sharp thing is.
Once you’ve checked it’s clear or pushed / pulled it out then it’s time to repair the tube.
Avoiding the issue
The first thing we’d say, is if you don’t have to fix the puncture, then don’t bother. Always carry at least one spare innertube and – once you’ve checked the tyre – stick that in instead. That way you can repair the puncture at home in your won time rather than sat on a hill in the rain.
The instructions for your puncture kit will be on or in the packaging somewhere, but it normally goes something like this;
1/ Find the hole/s. The bigger you pump the innertube up the larger the hole and the ‘hiss’ will be, but even if you find one obvious hole always check for others too. If you can’t see or hear the hole and there are no handy puddles nearby to look for bubbles in, then hold the tube next to your cheek and try and feel the air escaping that way.
2/ Use the little bit of sandpaper to roughen the tube around the hole, and use it to rub down any nearby seams on the tube. It sounds daft but it really does help as it takes the vulcanised outer layer off the rubber. Just don’t lose sight of where the actual hole is and make sure the rough area is bigger than the patch.
3/ Now coat the roughened area with a thin layer of rubber solution and let it dry while you get the right size puncture patch ready.
4/ Once the solution is dry, peel the foil backing off the patch and press it firmly on top of the hole. Hold it there for a couple of minutes.
5/ Peel the plastic sheet off the patch starting in the centre and working out rather than lifting from an edge, as that tends to pull the patch off. If the edge of the patch looks like it hasn’t stuck we normally smear a bit of extra glue around the outside to stick it down.
6/ Let the patch and any extra glue dry thoroughly and then inflate the tube slightly (so it takes shape but doesn’t stretch. If there’s still a hiss, check the patch and/or look for the other hole.
Make a second check of the inside of the tyre for any sharp objects by running your hand all the way round it. If it’s clear fit one edge of it onto the rim.
Tuck the innertube inside the tyre and fit the valve through the hole (but don’t tighten the lockring yet). Now start to fit the other edge of the tyre onto the rim, starting at the valve and working round. As you work round try and push / pull the tyre round the rim in the direction of the unfitted section. This will give you more slack to play with and make the final bit of fitting easier.
However cleverly you tuck the tyre on, there will come a point where either no more tyre will slip on, or it just starts peeling off at the far side. If you’re butch you can now use both hands to start levering the bead on with your thumbs, but beginners are best reaching for the tyre levers. Slide a lever under the tyre bead on either side of the section where it stops fitting onto the rim – be careful not to trap the tube under the lever.
Work the tyre on in small stages one lever at a time using a third lever if necessary to get the last bit on, while the other two levers hold the edge in place and stop it twanging off again. We’d love to explain it better but we tried and it just ended up more confusing, in practice just go slowly with plenty of patience and don’t try and lever too much tyre on in one go.
Now blow the tyre up to pressure (written on the side of the tyre) and check that it’s still sat on the rim all the way round and that it isn’t trapped in any places. Most tyres have a moulded line that sits just above the rim when it’s all settled comfortably. Congratulations, you are now ready to ride again!
Next week (if we get back from Shimano in Austria on time)Fixing your chain.