Tyre buffing is a process of shaving a portion of tread off a tyre in order to gain increased traction in dry tarmac conditions. This works largely by removing tread 'blocks', which are the areas of rubber between tread grooves. When the tyre heats up, these tread blocks expand and the surface area of the tyre which contacts the road decreases (and consequently traction also decreases). Tread blocks also heat up faster and again reduce traction. This overall process is referred to as 'tread flex'.
Tyre buffing minimises the problems associated with tread-flex by shaving the tread of a tyre until tread-flex is no longer a concern. The lower temperature which the tyre runs at decreases inflation pressure build up, and the absence of tread flex reduces irregular wear of the tyre shoulder.
The major disadvantage of tyre buffing is significantly reduced handling capabilities in the wet. With no tread grooves, the risk of aquaplaning is greatly enhanced. For optimal wet weather, new tyres with maximum tread depth are recommended.