Step 1: To remove the back wheel of your bike, first release the brake callipers: this is the mechanism above the back wheel, and it comes apart by separating the metal rod from one side and pulling one side up and away from the other.

Step 2: Ensure that the lowest gear is engaged.

Step 3: To remove back wheel, pull out and spin the lever on the opposite side to the gears.

Step 4: Remove the back wheel carefully, and place the frame of the bike down so as not to damage the frame.

Step 5: Remove the cap of the valve on the flat tyre and keep it somewhere safe. Depending on the type of valve you have, you may need to screw off the washer as well. Press the valve in to let all of the remaining air out of the tyre.

Step 6: To fix the puncture see our detailed guide in the current September/October 2010 issue of G magazine, on sale from September 1.

Step 7: To reattach the rear wheel pull the gears out from the frame, bring the wheel into position and then clip-in the gears.

Step 8: Push the lever on the gears down to engage them properly.

Step 9: Spin the lever on the opposite side to the gears clockwise to tighten. Then, you must ensure the lever is facing backwards so it doesn't get in the way when riding.

Step 10: Reattach the brake callipers. Check air, brakes, cables and chains before getting back on to ride. And don't forget your helmet!

Thanks to the Clarence St Cyclery for their expert advice and use of their workshop facilities. Their new women’s store opened earlier this year, and they now hold regular free bicycle workshops.