Patterns, tread design

FIGURE 14.15 Basic tread patterns (a) highway rib (b) highway rib/lug design (c) on/off highway (mixed service) (d) off highway. 

Rib designs with design elements principally in the circumferential direction are the most common type of tread pattern and show overall good service for all-wheel-position summer service. On heavy tmcks, they are used nearly exclusively on steer and trailer axles because of their lateral traction and uniform wear characteristics. Rib/lug combinations tend to find use on all-season tires, which require a balance of good tread wear, traction, and wet skid. On heavy-duty truck drive axles, where forward traction is a prime requirement and where fast tread wear occurs as a result of torque-induced slip, the highway lug design is required. For off-highway service conditions the tread pattern assumes a 

TABLE 14.3 Net-to-Gross Contact Area with Nature of Service [Ford and Charles, 1988 Clark, 1982] 

Type of Service % Net to Gross Relative Tread Depth Traction Handling Wear 

TABLE 14.4 Automobile Tire Tread Pattern Classes 

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Advancement in tire technology is expected to continue, to take advantage of emerging technologies, to meet further customer demands, and to accommodate new applications. Different tires will be introduced in the front and rear positions of automobiles as a result of the different loadings. Unsymmetrical tread designs will have different patterns on the outer and inner halves... 

Pitch length Length of each repeating unit in a tread pattern. Variable pitch lengths in a tread design can be used to minimize noise. Pitch would be analogous to the wavelength of a sine wave. 

The tire constmction influences both cornering and longitudinal slip stiffness. These include the tire carcass, breaker construction, inflation pressure, and tread pattern design. However, since the two stiffness components can be measured, knowledge of the construction details is not necessary. The vehicle geometry influences the tire wear through the air resistance, which it creates, and through the load distribution between front and rear axles. 

That portion of a vehicle tyre (pneumatic, semipneumatic or solid) which contacts the road surface. The tread pattern is so designed as to give the best combination of properties suitable for the conditions under which the tyre will be used. 

Other versions of the machine are designed for specific purposes, e.g., a twin ram machine capable of producing a continuous extrusion, and versions capable of applying tread rubber directly to a buffed tyre carcass whilst simultaneously forming the tread pattern. 

Because of the wide variations in operating conditions, tread and carcass blacks cannot be made in the same reactor however, all tread grades can be produced in the same reactor as is the case with all carcass grades. Unfortunately, exact reactor construction details and operating details are proprietary information and cannot be revealed however, exact internal configuration, dimensions, oil spray pattern, and burner design are all extremely critical for optimum quality and yields. One reactor will produce from 20,000-40,000 lbs/day, and a unit consists of from 4 to 5 reactors, discharging into common downstream facilities. 

Asymmetrical Tire design in which the tread pattern on one side of the centerline differs from that on the other side. 

The tread pattern influences the ability of the tire to transmit driving forces, braking, and lateral forces while operating on a broad range of highway and off-road surfaces. The design of a tread pattern is essentially the separation or division of a smooth tread into smaller elements or blocks. These ele-... 

Knowledge of non-linear contributions to viscoelasticity is important for design of elastomer blends and composites for rolling resistance performance of tyres, hysteresis and heat build-up behaviour, and friction or grip characteristics. The importance extends beyond developing suitable blend and filler compositions, to the construction, geometry and tread pattern design of tyres to arrive at optimum performance. 

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