We all know that tyres don`t last for ever but exactly when do they need replacing? Here`s how to tell when the time has come for a new pair.
There are essentially five parts to a clincher tyre (standard tyres that use inner tubes, held in place by a bead that hooks to the wheel rim, as opposed to tubulars that are bonded to the wheel):
Casing The supple body of the tyre, made of nylon (usually) in various numbers of threads per inch (TPI), that`s covered in rubber.
Protection layer Manufacturers sometimes use various different types of material underneath the tread to provide resistance against punctures.
Tread The compound that comes into contact with the ground.
Bead The bit around the edge that secures the tyre to the wheel rim. These are made from wire or foldable Kevlar.
Anti-chafing strip The reinforcement that protects the bead.
Impacts
Most road bike tyres will go through their lives without experiencing too much in the way of trauma, but you might hit a pothole, a big stone, or some other obstacle that causes damage to the structure, or something might ping up from the road surface.
Check your tyres carefully if anything like this happens.
Essex Potholes 3
[A casing breach of any size in the sidewall/ 2mm under the tread would usually render a tyre disabled and ready for replacement," says Shelley Childs of Cambrian Tyres, the company that distributes Continental bike tyres in the UK.
Pothole
[If you hit a pothole and feel the wheel rim has made contact with the road surface, then there is a chance that the tyre sidewall (casing) has been breached, even if there is no air loss of the inner tube. Stop and check.
[Also, if you ride over something that causes an obvious bump or jerk to the handling of the bike, your tyre may have been damaged, even if you don`t suffer a puncture. Again, stop and check just to be safe.
[If you do see a tear anywhere on the exposed surface of the tyre (tread or sidewall), inspect it thoroughly and try to see if the inner tube is visible. If so, the tyre is unsafe. If not, then the casing should still be intact and you can ride on, but get the tyre checked by your local dealer just to be sure."
Check the wheel too.
[If the tyre/tube survives a pothole smash then it`s essential that after you`ve checked the tyres you should also check your rims to make sure that their structure hasn't been compromised," says Schwalbe's Dave Taylor. [A dented rim or displaced spoke can cause unwanted friction for tyre and tube which could lead to a puncture on a later ride."
