Tramlining is a phenomenon in which the vehicle's wheels tend to follow the contours in the surface upon which it runs. The term comes from the tendency of a car's wheels to follow the normally recessed rails of street trams, without the driver’s input in the same way that the train does. This condition is called tram lining in Britain and the same effect is sometimes called Nibbling everywhere else.
Tramlining is generally blamed on the tires, and its incidence depends greatly upon the model of the tire and its state of wear and tear. It is generally not dangerous but at very high speeds it can become a source of instability. Tyre design plays a crucial role in nibble — the designers need to space the tread grooves so that they don’t match with the grooves in the pavement. Radial tyres, with their more flexible sidewalls, are less prone to nibble.
Vehicles with large and wide low profile wheels are more prone to its effects as well as vehicles which have wheels fitted that are larger than the ones recommended by the manufacturers or if they have reinforced sidewalls. People who are relatively inexperienced with driving in this tendency will feel that they have continuously have to make course corrections though, it is very easy to overcompensate the steering, that can potentially lead to veering off the road especially if the road is a thin track or a country road.
The effects of nibbling can be eased by subjecting the car to an inspection and calibration of the wheels (that is, a full geometry check) or replacing the tires with non – reinforced (with soft sidewall) ones.