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 pneumatic tire includes center lug grooves disposed at intervals in a tire circumferential direction that extend crossing a tire equator line and include a first groove turning portion and a second groove turning portion; shoulder lug grooves disposed in the intervals between the center lug grooves in the tire circumferential direction extending outward in the tire width direction, an inner end in the tire width direction being disposed outward of an end of the center lug groove in the tire width direction; a pair of circumferential main grooves to which the ends of the center lug grooves and the inner ends of the shoulder lug grooves in the tire width direction alternately connect; and a circumferential secondary groove disposed around the entire circumference of the pneumatic tire that intersects the center lug grooves between the first groove turning portion and the second groove turning portion.

A pneumatic tire comprising circumferential main grooves, a land portion defined by the circumferential main grooves, and a plurality of lug grooves disposed in the land portion that open to the circumferential main grooves. The land portion comprises notch portions formed on opening portions of the lug grooves and chamfered portions formed on edge portions of the notch portions. The notch portions have an edge portion with a V-shape projecting in a tire circumferential direction. A maximum width W2 of the notch portions and a width W3 of the chamfered portions have the relationship 0.30≦W3/W2≦1.80.

A tire includes knob sets having leading edge bevels connected by a ramp. The leading edge bevels may be offset in their positions or angles. Each knob set includes a first knob attached to a second knob. The knobs in each set may differ in lengths or in the angles of the leading edge bevels. Each knob set shares a common base and includes a pair of elongate outermost surfaces divided by an optional axial channel. Each knob set includes a lateral edge, medial edge and a trailing edge. Transverse rows of two or more knob sets may vary in lateral spacing between knob sets to provide narrow and wide rows in an alternating pattern. Knob sets may also be included on sidewalls of the tire.

A tread portion is provided with a first block and a second block, which protrudes outward in a tire width direction more than the first block, alternately in a tire circumferential direction in a shoulder region. A first projection is provided in an outer side of the first block, and a second projection is provided in an outer side of the second block. An outside end of the second projection is connected to a side surface of the second block and is arranged closer to an outer side in the tire diametrical direction than an outside end of the first projection. An angle θ1 formed by a side surface of the first projection and a surface of the side wall portion is equal to or smaller than an angle θ2 formed by a side surface of the second projection and the surface of the side wall portion.

A tread portion is provided with a first block and a second block, which protrudes outward in a tire width direction more than the first block, alternately in a tire circumferential direction in a shoulder region. A first projection is provided in an outer side of the first block, and a second projection is provided in an outer side of the second block. An outside end of the second projection is connected to a side surface of the second block and is arranged closer to an outer side in the tire diametrical direction than an outside end of the first projection. An angle θ1 formed by a side surface of the first projection and a surface of the side wall portion is greater than an angle θ2 formed by a side surface of the second projection and the surface of the side wall portion.

A pneumatic tire of the present disclosure includes, on a tread surface, circumferential main grooves extending in a tire circumferential direction and land portions defined between circumferential main grooves adjacent in a tire width direction among the circumferential main grooves or by the circumferential main grooves and tread edges. The land portions include widthwise grooves extending in the tire width direction and are divided into blocks by the widthwise grooves. At least one widthwise sipe extending in the tire width direction is included within the blocks. Hard rubber with a higher elastic modulus than that of tread rubber is disposed in a tire radial region including at least an opening to the tread surface of a wall defining the widthwise sipe. Microfabrication is applied in a region of the tread surface surrounding at least a portion of the opening of the widthwise sipe to the tread surface.

The invention relates to a pneumatic vehicle tire having a tread with profile block rows (1, 2) with profile blocks (5) delimited by channels (3, 4), which channels (3, 4) form T-shaped intersections in plan view and are delimited by a channel base (6, 6′) and by block flanks (5a, 5′a), wherein, in channels (3), there are formed projections (7, 7′) which, in a radial direction, have at their highest point a height (h.sub.1, h.sub.1′), in relation to the lowest point of the channels (3), of 10% to 80% of the profile depth. The projections (7, 7′) are positioned in intersection regions of T-shaped intersections of the channels (3, 4) and are attached to that block flank (5a) which is situated opposite the opening-in point of the opening-in channel (4).

The invention relates to a pneumatic vehicle tire having a tread with profile block rows (1, 2) with profile blocks (5) delimited by channels (3, 4), which channels (3, 4) form T-shaped intersections in plan view and are delimited by a channel base (6, 6′) and by block flanks (5a, 5′a), wherein, in channels (3), there are formed projections (7, 7′) which, in a radial direction, have at their highest point a height (h.sub.1, h.sub.1′), in relation to the lowest point of the channels (3), of 10% to 80% of the profile depth. The projections (7, 7′) are positioned in intersection regions of T-shaped intersections of the channels (3, 4) and are attached to that block flank (5a) which is situated opposite the opening-in point of the opening-in channel (4).

A tire assembly according to the disclosure may include a wheel having a first outer circumferential surface and a second outer circumferential surface, and a tire mounted on the wheel and having a first portion that mates with the first outer circumferential surface of the wheel, and a second portion that is spaced away from the second outer circumferential surface of the wheel to form a cavity. Furthermore, the first portion may be a solid portion that extends from the first outer circumferential surface of the wheel to an outer circumferential surface of the tire.