Original Equipment (OE) describes any vehicle component (tyre, battery, exhaust etc) that is supplied to the vehicle manufacturer for factory-fitting to a specific model.
In the case of tyres, vehicle manufacturers will usually source OE tyres from at least two different tyre manufacturers. The process of supplying tyres to a vehicle manufacturer is referred to as homologation. The homologation process can take up to two years and is a complex procedure between the tyre and vehicle manufactures.
In many cases an OE tyre is specifically matched to a particular vehicle – more common in high performance vehicles. For instance, all tyres that are supplied to Porsche are marked with the letter ‘N’ followed by a number – N-1, N-2 etc. It is advisable in these cases to fit only tyres that are approved by the vehicle manufacturer.
Most tyre manufacturers will recommend that replacement tyres are of the same specification as those originally chosen as OE by the vehicle manufacturer.