Happened before with Conti motorbike tyres …
“The orientation of the ContiRoad Attack front has recently been revised. Conti Germany responded to feed-back from the UK and other markets about maximising the already incredible durability of the original front tread pattern. After the launch of the ContiSport Attack test riders commented on the fact that the reversed tread direction gave much more uniform wear across the tyres section and so the ContiRoad Attack front pattern was switched in late October 2006 to take advantage of this better wear characteristic. Some confusion exists because some European plants outside of Germany have a tread mould with small arrows at the edge of the tread near the sidewall, these arrows should be ignored. These moulds are being replaced. ContiRoad attack customers may be offered the same tyre with apparently two different directions of rotation. The tread pattern on both tyres is fine. Riders should be aware that all relevant and legally required information regarding speed rating and direction of rotation is moulded into the side-wall of the tyre, not the tread, so be sure your tyre is fitted in accordance with the directional arrow on the sidewall regardless of which way the pattern runs.” :?