This video is a little misleading. The video shows on 2 occasions (one with the 20p & the other with the digital tread depth gauge) measurements being taken in the “sipes” area of the tyre. The “sipes” are the outermost grooves of the tread area located on each shoulder of the tyre. These “sipes”, which will almost always will be outside the central 75% (3/4) breadth of the tread area do not make up part of the tread grooves and do not need to be there, manufacturers sometimes add these “sipes” as an additional feature to the tyres design but there is no legal requirement for them to exist. The grooves of tread where tread depth readings should be taken from will be identifiable as they will have tread wear indicators featured.
