Mending inner tubes
How to inflate that flat tyre on your bike.
WE’VE all been there: you’re just about to head out when you realise your bike has a flat tyre. But you won’t need a book of magic tricks to fix it.
“The inner tubes lose air when the bike hasn’t been used in a while,” explains bike repair specialist Gunnar Fehlau. “It’s a good idea to pump up the tyres to the maximum pressure indicated on the sidewall the night before a bike ride. If the tyres are still at full pressure the next morning, you’re good to go.
“But you’re not always that lucky,” says David Eisenberger from the German Bike Industry Association. Anyone using a bicycle on a regular basis will inevitably be confronted with a flat tyre at some point.
Get your tool box out
First, the wheel needs be taken off. Removing it is easier than ever, thanks to the quick releases that are usually installed.
You’ll still need some tools. Fehlau recommends a multitool, two tyre levers and a mini pump. “You’ll also need a wrench if the wheels are not fitted with a quick-release.”
Once you have everything, you can begin. “First, use the tyre lever to prise the casing off the rim on one side so that the tube can be pulled out,” explains Eisenberger.
Find the puncture
Submerging the tube in a tub of water and looking for air bubbles is a tried and tested method. “However, this is not always possible on the road.”
Fehlau therefore carries a puncture finder with him. This is a small gadget filled with polystyrene balls. “When placed over a puncture, the balls move due to the escaping air.” Once the puncture has been identified, which should not be larger than 3mm, the repairs are relatively simple. Fehlau recommends buying a kit that contains everything you need.
“Lightly rub the damaged area before applying the patch,” explains Eisenberger, who recommends using self-adhesive patches as they are a lot easier to handle. “Pressing down hard in the first 15, 20 seconds makes all the difference and ensures everything is securely stuck down,” explains Fehlau.
Check for remnants
Before sticking the tube back in the rim, a few safety precautions need to be taken. “You should check if there are remnants of the offending item on the inside of the tyre, such as a thorn or a piece of glass,” says Fehlau.
Something like that would have to be carefully removed. Fehlau recommends using rim tape, which prevents the tube from having direct contact with the inside edges of the rim.
Once you’ve done all of this, “the repaired tube can be put back in and the outer tyre can be remounted onto the rim,” says Eisenberger. Don’t forget to put the valve through the valve stem in the wheel rim.
In conclusion, he advises replacing the tube you’ve repaired with a new one. “No matter how good the quality of the repair kit, patching up a bike puncture is still an emergency solution.”