SAE J1269

	SAE J1269 SAE J1269 is a standard test defined by the Society of Automotive Engineers to measure the rolling resistance of tire A tire (American English) or tyre (British English) is a ring-shaped component that surrounds a wheel's rim to transfer a vehicle's load from the axle through the wheel to the ground and to provide traction on the surface over which t ...s under conditions of thermal equilibrium. SAE J2452 is an alternative procedure for measuring rolling resistance under conditions similar to a vehicle coastdown event, where the tire is in a roughly isothermal condition (but not thermal equilibrium). The rolling resistance coefficient (RRC) thus measured indicates the proportion of energy that is lost to the hysteresis of the material as the tire rolls. References Tires {{automotive-tech-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
picture info	Society Of Automotive Engineers SAE International, formerly named the Society of Automotive Engineers, is a United States-based, globally active professional association and standards developing organization for engineering professionals in various industries. SAE International's world headquarters is in Warrendale, Pennsylvania, 20 miles north of Pittsburgh, Pennsylvania. Principal emphasis is placed on global transport industries such as aerospace, automotive, and commercial vehicles. The organization adopted the name SAE International to reflect the broader emphasis on mobility. SAE International has over 138,000 global members. Membership is granted to individuals, rather than companies. Aside from its standardization efforts, SAE International also devotes resources to projects and programs in STEM education, professional certification, and collegiate design competitions. For historical legacy reasons, the label "SAE" is commonly used on tools and hardware in North America to indicate United States ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
picture info	Rolling Resistance Rolling resistance, sometimes called rolling friction or rolling drag, is the force resisting the motion when a body (such as a ball, tire, or wheel) rolls on a surface. It is mainly caused by non-elastic effects; that is, not all the energy needed for deformation (or movement) of the wheel, roadbed, etc., is recovered when the pressure is removed. Two forms of this are hysteresis losses (see below), and permanent (plastic) deformation of the object or the surface (e.g. soil). Note that the slippage between the wheel and the surface also results in energy dissipation. Although some researchers have included this term in rolling resistance, some suggest that this dissipation term should be treated separately from rolling resistance because it is due to the applied torque to the wheel and the resultant slip between the wheel and ground, which is called slip loss or slip resistance. In addition, only the so-called slip resistance involves friction, therefore the name "rolling fri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
picture info	Tire A tire (American English) or tyre (British English) is a ring-shaped component that surrounds a Rim (wheel), wheel's rim to transfer a vehicle's load from the axle through the wheel to the ground and to provide Traction (engineering), traction on the surface over which the wheel travels. Most tires, such as those for automobiles and bicycles, are pneumatically inflated structures, which also provide a flexible cushion that absorbs shock as the tire rolls over rough features on the surface. Tires provide a footprint, called a contact patch, that is designed to match the weight of the vehicle with the bearing strength of the surface that it rolls over by providing a bearing pressure that will not deform the surface excessively. The materials of modern pneumatic tires are synthetic rubber, natural rubber, fabric, and wire, along with carbon black and other chemical compounds. They consist of a tire tread, tread and a body. The tread provides Traction (engineering), traction ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	SAE J2452 SAE J2452 is a standard defined by the Society of Automotive Engineers to measure the rolling resistance of tires. Where the older standard, SAE J1269, produces measurements of rolling resistance under steady-state (i.e. thermally equilibrated) operating conditions, SAE J2452 produces measurements during a transient history of speed that is intended to mimic a vehicle coastdown event. During the SAE J2452 test, the tire is not in thermal equilibrium, but the coastdown event is rapid enough that the tire operates at a roughly iso-thermal condition. Either procedure may be used to investigate the effects of different vehicle loads (weight), tire pressures and vehicle speeds. The rolling resistance coefficient (RRC) indicates the amount of force required to overcome the hysteresis of the material as the tire rolls. Tire pressure, vehicle weight and velocity all play a role in how much force is lost to rolling resistance. The basic model equation for SAE J2452 is: ::''Rolling Resist ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
picture info	Rolling Resistance Coefficient Rolling resistance, sometimes called rolling friction or rolling drag, is the force resisting the motion when a body (such as a ball, tire, or wheel) rolls on a surface. It is mainly caused by non-elastic effects; that is, not all the energy needed for deformation (or movement) of the wheel, roadbed, etc., is recovered when the pressure is removed. Two forms of this are hysteresis losses (see below), and permanent (plastic) deformation of the object or the surface (e.g. soil). Note that the slippage between the wheel and the surface also results in energy dissipation. Although some researchers have included this term in rolling resistance, some suggest that this dissipation term should be treated separately from rolling resistance because it is due to the applied torque to the wheel and the resultant slip between the wheel and ground, which is called slip loss or slip resistance. In addition, only the so-called slip resistance involves friction, therefore the name "rolling frict ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]