A loud bang and a long walk

Inflating an old bicycle tyre to almost twice its rated pressure is not a clever idea :)
It appears that a special form of Murphy's law dictates that the tyre will hold up to this pressure until it is located at the exact point in any given city that is the maximum distance from the nearest bike shop, at which point it will suddenly and violently decline further service. Applications for this law (other than deciding where to open new bike shops) are still under investigation.