The tyre debris, often seen at the roadside, does not necessarily come from retreaded tyres and is mainly the result of under inflation or overloading. Retreaded tyres are used extensively on aircraft and in motoring competition. There are many dangers in buying part-worn or second hand tyres. Their history is unknown and they may have been removed from a vehicle involved in an accident or have been badly damaged by kerbing or similar problems. Repairs may not have been carried out properly, for example to British Standard BS AU 159f.
Some faults only show up if the tyre has been inflated.
Tread depth must be at least 2mm across the whole breadth of tread. Mixing of tyres Except in the case of temporary use spare tyres, it is illegal in the United kingdom, and it is certainly dangerous, to mix radial ply and cross ply tyres on the same axle or to have radial ply tyres on the front axle and cross ply tyres on the rear axle. This applies to all two axle motor vehicles whether front or rear wheel drive. The type of tyre is indicated on the sidewall markings. In the case of radial tyres the word radial is written on the sidewall.