ISO 28580 Wheel Radial Load Fatigue Testing for Methods of measuring rolling resistance Single point test Passenger car truck, bus and motorcycle
ISO 28580 Passenger car truck, bus and motorcycle tyres — Methods of measuring rolling resistance Single point test Standard specifies methods for measuring rolling resistance, under controlled laboratory conditions, for new pneumatic tyres designed primarily for use on passenger cars, trucks, buses and motorcycles. The relationship between values obtained and the fuel economy of the vehicle is undetermined, and such values are not intended to be used to indicate levels of performance or quality.
This International Standard applies to all passenger car, truck, bus and motorcycle tyres. Measurement of tyres using this method enables comparisons to be made between the rolling resistance of new tyres when they are free-rolling straight ahead, in a position perpendicular to the drum outer surface, and in steady-state conditions. In measuring tyre rolling resistance, it is necessary to measure small forces in the presence of much larger forces. It is, therefore, essential that equipment and instrumentation of appropriate accuracy be used.
4 Test methods
The following are alternative measurement methods. The choice of an individual method is left to the tester.
For each method, the test measurements shall be converted to a force acting at the tyre/drum interface. The measured parameters are given below.
a) Force method: the reaction force measured at the tyre spindle. This measured value also includes the bearing losses of the tyre spindle and the aerodynamic losses of the tyre and the wheel.
b) Torque method: the torque input measured at the test drum.
c) Power method: the measurement of the power input to the test drum.
d) Deceleration method: the measurement of deceleration of the test drum and tyre assembly.
NOTE This measured value also includes the bearing and aerodynamic losses of the wheel, the tyre and the drum, losses that are also to be considered.
Test equipment
Wheel Radial Load Fatigue Testing Machines (UT1015)
5.1 Drum specifications
5.1.1 Diameter
The test dynamometer shall have a cylindrical flywheel (drum)
with a diameter of at least 1,5 m (reference drum diameter: 1,7 m) for passenger car and motorcycle
tyres;
with a diameter of at least 1,7 m for truck/bus tyres.
It should be noted that the results are different for different diameters; see 9.3 for drum diameter correction for
comparisons, if necessary.
NOTE Historically, the measurement of the fore and aft (longitudinal) force on a flat surface machine has been shown
to be quite difficult since this force is very small relative to other forces being measured. If a flat surface machine is used,
care should be taken to correlate the data with the reference drum diameter in order to assure accurate results.
5.1.2 Surface
The surface of the drum shall be smooth steel or textured and shall be kept clean. For the textured drum
surface, see B.4.
5.1.3 Width
The width of the drum test surface shall exceed the width of the test tyre tread.
5.2 Test rim
The tyre shall be mounted on a test rim, as specified in Annex C.
5.3 Load, alignment, control and instrumentation accuracies
Measurement of these pa
