Part-worn tyres are - on the face of it, in these straitened times - an obvious economy. On a market where premium tyres from the likes of Michelin, Goodyear, Continental, Dunlop, Bridgestone or Pirelli can cost over £100 a corner, part-worn tyres may offer a full set or rubber for £40.
That's a staggering saving, particularly with motorists looking to save cash as petrol prices rise, insurance premiums soar and the general cost of living continues its upward journey.
Part-worn tyres offer a legal alternative to all-new tyres, with 3mm common tread depths against the legal limits of 1.6mm.
However, many new tyres offer 6.4mm of useable tread from the entire 8mm, so part-worn tyres are the very definition of a false economy - regardless of the safety implciations.
And those safety implications are severe. Defective tyres were blamed for 1,210 casualties on British roads last year - a statistic blamed on ignorance of tyre safety and maintenance as much as motorsts' 'economy-first' attitude to motoring.
More than 35 per cent of motorists are currently purchasing second hand or used tyres according to fast-fit network HiQ.
HiQ says that part-worn tyres can be sourced from written-off cars or imported from Eastern European scrapyards. These tyres can conceal structural defects not clear to the naked eye and can also add two car lengths to a car’s stopping distance in the wet.
We've taken identical cars around a wet testing circuit to compare part-worn tyres to new tyres, in this case both standard Goodyear tyres on a Volkswagen Golf BlueMotion. The difference was startling.
Driving at a stable 30mph, in a manner akin to driving around a roundabout, the part-worn tyres were unable to keep traction on the wet surface, with front and rear wheels fighting for grip - and losing. While great for a spot of drifting, the ramifications for the unprepared driver in real-world conditions were clear.
The all-new tyres held on to grip much longer - and only at around 40mph showed signs of terminal understeer, with more and more lock required to complete the circuit around the course.
Even if the safety reasons are not considered strong enough to spend the extra cash on new tyres the economical arguments don't exactly stack up for part-worn tyres. A part-worn circle is likey to offer 1.4mm of useable tread; a new tyre offers over four times as much.
Part-worn tyres aren't just a poor safety choice; they're a poor economic choice.