When setting up a vehicle for sand, it is advisable to avoid tires with sharp shoulder transitions as shown here. To better understand why, think of cutting a birthday cake. With a sharp knife, the cake cuts easily, allowing the blade to sink through to the bottom. Attempt to cut the same piece of cake with the curved surface of a spoon, and you will simply displace cake and make a mess. The same principle holds true for tires. Patterns with rounded-edge lugs provide much better flotation in the sand than sharp squared-off lugs.