Document ID: chunk:federal_register_of_legislation:F2012C00535:front:0:p18
Version: federal_register_of_legislation:F2012C00535
Segment Type: other
Provision Reference: 
Character Range: 50907–53693

distance from centre of wheel on 1st axle to centre of wheel on second axle
        L2  =  the distance from centre of wheel on 1st axle to centre of wheel on third axle, if
                  fitted

Figure A3.1 - Longitudinal position of the centre of gravity

       2.5. The transverse position (t) of the vehicle's centre of gravity relative to its longitudinal vertical centre plane  (see figure A3.2) is given by,

       where:

            T1  =   distance between the centres of the footprint of the wheel(s) at each end of the first axle
            T2  =   distance between the centres of the footprint of the wheel(s) at each end of the second axle
            T3  =   distance between the centres of the footprint of the wheel(s) at each end of the third axle

       This equation assumes that a straight line can be drawn through the centre points of  T1, T2, T3.  If this is not the case then a specialised formula will be required.

       If the value of (t) is negative, then the centre of gravity of the vehicle is situated to the right of the centreline of the vehicle.

Figure A3.2 - Transverse position of centre of gravity

       2.6. The height of the centre of gravity (h0) shall be determined by tilting the vehicle longitudinally and using individual load-cells at the wheels of two axles.

       2.6.1. Two load-cells shall be positioned on a common horizontal plane, to receive the front wheels.  The horizontal plane shall be at sufficient height above the surrounding surfaces that the vehicle can be tilted forward to the required angle (see paragraph 2.6.2. below) without its nose touching that surface.

       2.6.2. A second pair of load-cells shall be placed in a common horizontal plane on top of support structures, ready to receive the wheels of the second axle of the vehicle.  The support structures shall be sufficiently tall to generate a significant angle of inclination  (> 20) for the vehicle.  The greater the angle, the more accurate will be the calculation – see figure A3.3.  The vehicle is repositioned on the four load-cells, with the front wheels chocked to prevent the vehicle rolling forward.  Each steered wheel shall be set to its straight-ahead steer position.

       2.6.3. The individual load-cell readings shall be noted simultaneously and shall be used to check the total vehicle mass and centre of gravity position.

       2.6.4. The inclination of the tilting test shell be determined by the equation (see figure A3.3)

       where:

       H  =   height difference between the footprints of the wheels of the first and second axles
       L1  =   the distance from centre of wheel's first and second axles

       2.6.5. The unladen kerb mass of the vehicle shall be checked as follows:

Ftotal = F1+F2+F3+F4