It ’ s been a stalwart of the big Adventure Bike segment for ages ... but the Metzeler Karoo 3 is dead . Long live the Karoo 4 ! Metzeler has debuted its latest 50-50 tyre option which is said to focus on versatile grip for adventure class and large road-legal enduro bikes , with the new Karoo 4 picking up where the highly respected Karoo 3 left off . The new Karoo 4 ’ s patented tread design aims to raise the tyre ’ s all-around performance levels on both asphalt and on different types of offroad terrain . This comes in part from a greater contact patch with a great number of knobs in contact with the road compared to the Karoo 3 , with Metzeler saying that this also helps improve handling and integration with bikes with electronic rider aids . In particular , Metzeler engineers worked to improve on the overall handling and wet behaviour of the Karoo , developing a knobbly pattern that allows riders to safely tackle certain lean angles even in wet conditions . In the off-road field , Karoo 4 increases the performance level , especially on very soft surfaces , such as sand , mud and clay . Like the Karoo 3 , the Karoo 4 caters for tyre sizes from 19-inch to 21-inch front wheels and 17 and 18-inch options for the rear .