How to repair a mountain bike tyre | School camps South Australia
December 6, 2021
Did you know Beyond the Classroom can run a bike education "incursion" at your school? Learn how to do basic bike maintenance and more. These are ideal to do prior to a mountain bike school camp in South Australia.
Suffering from a flat tyre is part and parcel of cycling, regardless of the bike you use or your riding activity. Fixing a flat tyre is relatively easy especially with some basic tools, a bit of guidance, and after a few goes you'll see it as a short lived inconvenience.
There are two types of flat tyres to change, those with a tube and those known as 'tubeless'. This article focuses on changing a tyre with a tube.
If you are out riding when you get a puncture and it is going down fast, you'll need to fix it on the spot to prevent damage to your wheel rim. Make sure you move off the trail and to a space that is safe from passing vehicles, other riders and any other obstacles.
Remove your damaged wheel from the bike. You may find it easier to flip your bike upside down to release the wheel. Most bikes have a quick release system but if not, use either the correctly sized Spanner or Allen Key to release the wheel. If you are working with your front tyre, simply lift it away from the frame once released. The back tyre is slightly more complicated to lift out as you need to navigate around the derailleur and chain. We recommend placing a thumb on the derailleur, pushing it back slightly while lifting the wheel out of position. Then place a finger around the chain and move it out of the way of the cassette while you free the wheel.
Now that your wheel is free from the frame, you need to make sure the tube is completely deflated. To do this, open the valve and press gently on the valve core to release any remaining air. If you leave air in the tube you will find it is harder to break to bead (the part of the tyre that seals to your rim for your wheel).
Disengage the bead of your tyre from the wheel rim. To do this pull the tyre back from the rim all the way around your wheel on both sides.
Remove the tyre from the wheel rim. Start at a point away from the valve. Pinch the tyre with your whole hand so that the tips of your fingers sit on edge of the bead, then as you roll your wrist back, lift the tyre up as you pull you the wheel down with the opposite hand. This will allow enough room to then lift the tyre up and over the rim and pull it down. Move your hands around the side of the inner rim to lift the rest of the tyre away the wheel rim.
*We highly recommend watching this process on our quick video to see how this is done.
Note: If you are finding you can not create enough space to pull the tyre over the other side of the rim, go back and make sure you have got all the air out of the tube. If you are still having trouble, you may need to resort to using tyre levers for additional leverage. When using tyre levers, start on the section of your tyre opposite the valve (to avoid damaging the valve stem). Plastic tyre levers are more preferable to metal ones as they minimise the potential damage to the bead that can be caused.
Pull the tube out. Note you may need to unscrew the valve from the wheel rim to do this. Run your fingers around the inside of the tyre to check for what may have caused your puncture. Be careful as it could be a piece of glass. Remove anything that could be the cause to prevent future punctures.
It's time to repair your tube. You will need a tube repair kit for this. Inflate your tube and trace any signs of air coming from a hole. If you have access to water, then submerge the inflated tube in water and look for bubbles. Once you have located the hole, mark the area so you do not loose it. You will now need to deflate the tube entirely to repair the hole. Use sandpaper or the metal sanding pad supplied in the repair kit to lightly scratch an area larger than the repair patch you plan to put over the hole. This helps the glue stick to the tube. Apply a thin layer of glue to the whole area you have scratched. Allow it to dry before putting the patch on. It's a good idea to apply pressure down on the patch once applied.
The last step is to put your tube back in the tyre and then the wheel back on the bike. Start with putting the tyre back on the wheel. You need to put one side of the bead on first, making sure the other sides bead does not hook on in the process. Be mindful of getting the tread rotation correct as well.
Before putting the tube in, add a small amount of air so that it holds shape. Match the valve on the tube to the valve hole on the wheel rim. Starting at the valve, push the remaining side of the tyre back on to the wheel rim. You need to work your way around both sides evenly. The last part will become quite tight. Use the same grip you did to pull off the tyre to now leverage it until it pops back on.
Inflate your tyre half way and check the bead has grabbed on both sides. You should be able to see the line of the bead all the way around the tyre. Lastly inflate your tyre to the recommended PSI. Place the wheel back on to the bike using the reverse of what you did to remove it.
Here’s a pro tip repair hack: If you punch a hole in the sidewall of a tyre, insert some folded paper, a $5 note or empty plastic wrapper on the inner wall of the tyre and pump it up to full pressure. The barrier can help prevent the tube from pushing out of the hole, hopefully long enough to get back to your car or house.
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