Provided are tractor wheels for a downhole tractor. An example tractor wheel comprises a series of continuous springs disposed on the circumference of the tractor wheel, wherein the individual continuous springs in the series of continuous springs are separated by a gap, and a void disposed on the interior of the tractor wheel and that is continuous about the circumference of the tractor wheel.

A tread pattern of a tire includes: a circumferential main groove extending in a tire circumferential direction; a plurality of sipes extending in a tire width direction within a region of a land portion in contact in the tire width direction with the circumferential main groove; and a chamfered surface having a tread surface of the land portion inclined toward the circumferential main groove in an end portion in the tire width direction on a circumferential main groove side of the land portion, the chamfered surface being provided in a plurality in the tire circumferential direction, and the sipes opening to the plurality of the chamfered surfaces without reaching a groove wall of the circumferential main groove. The length of the chamfered surface in the tire circumferential direction is greater than the length thereof in the tire width direction.

A tire tread includes a pair of first circumferential main grooves in a first half-tread region on one side in a tire width direction, a pair of second circumferential main grooves in a second half-tread region, first sipes provided in a first region between the first circumferential main grooves, a circumferential narrow groove having a groove width smaller than a groove width of the first circumferential main groove and extending in the tire circumferential direction within the first region, and sipes in a second region between the second circumferential main grooves, extending in the tire width direction, and closing within the second region. The number of intervals of the second sipes mutually adjacent is larger than the number of intervals of the first sipes mutually adjacent.

A tire includes a tread portion including first and second tread edges, three or more circumferential grooves, and four or more land portions. The circumferential grooves include a first shoulder circumferential groove nearest to the first tread edge. Each land portion is provided with only sipes and is not provided with lateral grooves. The land portions include a first shoulder land portion having the first tread edge, and a first middle land portion adjacent to the first shoulder land portion. The first middle land portion is provided with first middle sipes traversing the first middle land portion completely in the tire axial direction. The first shoulder land portion is provided with first shoulder sipes extending from the first shoulder circumferential groove to the first tread edge. The first shoulder sipes have a circumferential pitch length smaller than a circumferential pitch length of the first middle sipes.

A tire includes a tread portion including a first tread edge, a first shoulder circumferential groove, and a first shoulder land portion demarcated by the first shoulder circumferential groove to include the first tread edge. The first shoulder land portion is provided with first shoulder lateral grooves extending from the first shoulder circumferential groove to the first tread edge. One of the first shoulder lateral grooves includes first and second groove walls which face each other, and a tie-bar. The tie-bar includes an outer surface extending along a ground contact surface of the first shoulder land portion, the outer surface being connected to the first and second groove walls. The outer surface includes a first edge connected to the first groove wall, and a second edge connected to the second groove wall, the second edge having a length smaller than a length of the first edge.

A tyre includes a tread portion including a first land portion having a circumferentially extending first edge and a circumferentially extending second edge on its ground contacting surface. The first land portion is provided with sipes each extending from the first edge to the second edge. The sipes include bent sipes each including two or more sipe elements joined with each other to form a bent portion. The bent sipes include first sipes and second sipes. Each first sipe, as the sipes elements, includes at least one first sipe element inclined in a first direction with respect to a tyre axial direction and at least one second sipe element inclined in a second direction opposite to the first direction with respect to the tyre axial direction. All sipe elements of each second sipe are inclined in the first direction with respect to the tyre axial direction.

A pneumatic tire includes: a plurality of shoulder blocks that are provided in a side portion, defined by a shoulder main groove extending in a tire circumferential direction and a shoulder lateral groove extending in a tire width direction, and disposed side by side in the tire circumferential direction; a rib that is provided in the side portion, and extends in the tire circumferential direction along the shoulder blocks; and a projection that is provided in the side portion, and extends from the rib toward the shoulder blocks.

A pneumatic tire comprises a tread portion provided with a pair of crown main grooves and a pair shoulder main grooves to divide middle portions and shoulder portions, the tread portion having a contact surface covered with a cap rubber layer with a loss tangent of from 0.03 to 0.18, the middle portions provided with only middle lug grooves with groove widths within 2 mm, each middle lug groove extending from one end connected either the crown or shoulder main groove to the other end terminating within the middle portion, the middle lug grooves having an angle of from 40 to 55 degrees with respect to a tire circumferential direction, and each shoulder portion provided with first shoulder lateral grooves having axially inner ends connected to the shoulder main groove, wherein first shoulder lateral grooves consist of grooves having groove widths within 2 mm.

The tread profile of a vehicle tire has a circumferential rib. Grooves are formed in the circumferential rib with a width, which increases along its entire extent, wherein the grooves are formed with a vertex point between a first portion and a second portion. The groove direction from the beginning to the vertex point is formed with a greater directional component in the circumferential direction than in the axial direction and between the vertex point and the entry into the circumferential groove is formed with a greater directional component in the axial direction than in the circumferential direction. The groove is formed in the first portion with a depth T.sub.1, which increases continuously from the beginning over the first portion up to reaching its maximum value T.sub.1max at the vertex point and is formed with a constant depth T.sub.2 in the second portion wherein T.sub.2≥T.sub.1max.

A pneumatic tire comprises a tread portion provided on each side of the tire equator with a middle land portion defined between a shoulder main groove and a crown main groove each extending continuously in the tire circumferential direction. The middle land portion is provided with axially inside middle lug grooves and axially outside middle lug grooves arranged alternately in the tire circumferential direction. The axially inside middle lug groove is connected to the crown main groove at an angle θ1 of from 20 to 45 degrees with respect to the tire circumferential direction and has an axially inner opened end and an axially outer closed end. The outside middle lug grooves is connected to the shoulder main groove at an angle θ2 of from 60 to 80 degrees with respect to the tire circumferential direction and has an axially outer open end and an axially inner closed end. The tread portion may be provided with a shoulder land portion comprising circumferential sipes, axial grooves terminating at the circumferential sipes, and a circumferentially continuous rib.