TIRE WITH SNOW SIPES

In one aspect, a tire has a tread portion with at least one tread block having an elongated shape extending transversely to a circumferential centerline and comprising a sipe with i) a pair of elongated sipe portions extending predominantly along the elongated shape, and ii) a joint sipe portion extending along the elongated shape, wherein the elongated sipe portions converge into the joint sipe portion. In another aspect, a sipe comprises along its elongated sipe portion a) a radially outer sipe portion extending with an undulated shape; b) a radially inner sipe portion, extending with an essentially linear shape; and c) a transition portion, provided radially between the radially outer sipe portion and the radially inner sipe portion, and having a shape radially transitioning from the undulated shape of the radially outer sipe portion to the linear shape of the radially inner sipe portion.