T-peel tearing of a model black-filled NR tread ply vulcanizate has been carried out. Tearing alternates between slow (“stick”) and fast growth stages (“slip”). “Stick” fracture involves sideways cracking into the loading direction. This blunts the peel front and delays forward tearing. It also leads to a rough fracture surface. “Slip” fracture is relatively smooth and occurs by sudden forward crack growth near the specimen's plane of symmetry. This basic “stick-slip” character also has been seen in edge-cut tensile specimens.