Search results
Results from the WOW.Com Content Network
SAE J1269 and SAE J2452 performed on new tires. SAE J2452 is a standard defined by the Society of Automotive Engineers [1] to measure the rolling resistance of tires. [2] 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 ...
Rolling friction, also called friction in rolling motion or rolling drag, is the force resisting the motion when a body (such as a ball, tire, or wheel) rolls on a surface. . In pure rolling motion, there is only one point of contact between the rolling object and the surface at any instant, and this point remains momentarily at rest relative to the surfa
Pressures below this leads to increased rolling resistance and likelihood of pinch-flats. Pressures above this leads to less rolling resistance in the tire itself but to larger total energy dissipation caused by passing vibrations to the bike and especially the rider, which experience elastic hysterisis.
Low rolling resistance tires are designed to reduce the energy loss as a tire rolls, decreasing the required rolling effort — and in the case of automotive applications, improving vehicle fuel efficiency as approximately 5–15% of the fuel consumed by a typical gas car may be used to overcome rolling resistance.
Hence, For bicycles (and less so for motorcycles) the total rolling resistance increases with increasing tire cross-section diameter. Rolling resistance measurements made on bicycle tires using test equipment not taking into account natural lateral/precessing motion do not accurately measure the rolling resistance of bicycle tires. [1]
In a non-scientific study (I looked at tires available from a national chain that fit my car), 85 percent of LRR tires had an “A” rating for traction, compared to 87 percent of Non-LRR tires.
SAE J1269 is a standard test defined by the Society of Automotive Engineers [1] to measure the rolling resistance of tires under conditions of thermal equilibrium. [2] [3] 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).
There are a number of variables that determine rolling resistance: tire tread, width, diameter, tire construction, tube type (if applicable), and pressure are all important. Smaller diameter wheels, all else being equal, have higher rolling resistance than larger wheels. [49] "Rolling resistance increases in near proportion as wheel diameter is ...