Having worked for Rover I am aware that the tyres fitted by the car manufacturer's are not necessarily the same as supplied by the same tyre manufacturer as replacements. I know we had specials made , for which we paid the tooling. with a slightly modified tread pattern to eliminate a particular resonant noise. I did ask what happens when you need replacements and was told it would normally be a " generic" tread pattern for that brand and designation. Its all aimed at getting the original purchaser to be satisfied , not subsequent ones.