Most roads regardless of how smooth they look, have longitudinal grooves. Some wide, some small. Depending on what part of the country or what part of the world you live in, you will see different types of road surfaces and conditions. Because the Ninja has narrow tires it is easy for it to do what some call tramming or tramlining. That is where the tire rides in and up or up and over a groove, giving the feeling like the rear or whole vehicle is moving from side to side. It's like going over a grated bridge, you get the side to side movement because the tires are riding on grooves int the metal. Add in the crown of the road, tar patches, sand, loose pavement, water, antifreeze, oil, transmission fluid, rubber residue, and whatever else rolls across the road, there is no telling what is the actual cause of lateral slipping. The remedy? Be more observant of the road surface your are riding on, take the appropriate action for the riding condition, then...just lean wit it, rock wit it, roll wit it!! 8)
