Thank you for your responses. Further to these and another from mytyres I have now fitted them. See latest response from mytyres giving a fuller explanation. I still think it doesn't make sense having the tread running in opposite directions, however lets see how they work! 'We would like to inform you that if the tread pattern seems to have a different orientation on either side of the car, this will not change anything with the overall performance of the tyre. There will be no problem if the grooves on one side of the car point upwards and on the other side downwards, after you fit these asymmetric tyres. The long, steep grooves on the outer shoulder of the tyres are designed to direct as much water as possible to the outside via the shortest way and therefore in shortest possible time. These tyres are designed in such a way that the water can be drained in the direction of the shoulder, to the outside, as well as in direction of the deep circumference grooves. The angle in which they run has no impact on the aquaplaning performance and the driving comfort of the tyre. ' Roger.