AS ISO 7457:2021 Earth-moving machinery一Determination of turning dimensions of wheeled machines.
outer and inner tyre clearance diameter
Diameter of the circular path described by the outermost point of the loaded (lower) section of the tyre located on the vertical diameter of the outermost wheel and also that of the innermost point of the innermost wheel when the machine is executing its sharpest practical turn under the conditions described in clause 7. (See figures 1 and 2.)
See clause 6 for the state of loading of the machine.
non-stop 1800 turn width
Minimum road width required for the tyre paths of the machine as it makes a 1800 turn without stopping. (See figure 3.)
4 Test area
The test area shall be a compacted or paved surface affording good tyre adhesion, capable of displaying legible markings and resistant to defacement by turning machines. The test surface shall be visually flat, with no more than 3 % grade in any direction. The test area shall be large enough to accommodate the test machine as it negotiates the appropriate tests.
5 Test equipment
The following equipment or its equivalent shall be provided.
6 Preparation for test
6.1 The track of machines having adjustable track axles shall be measured and recorded. The lyre pressures shall be adjusted to those recommended by the manufacturer of the machine. If the manufacturer specifies various pressures or ballast according to ground conditions then those specified for a hard surface shall be used. The tyre sizes and pressures used shall be recorded.
6.2 The machine to be tested shall be in its operating condition, and the equipment and the attachments with which it is equipped and their positions shall be noted.
6.3 Movable equipment shall be in its recommended transport position.
6.4 Load-carrying equipment shall be laden or empty as specified in 6.4.1 to 6.4.3 (see ISO 5010).
6.4.1 Tractor-scrapers and dumpers shall be at the manufacturer’s rated maximum gross mass and axle distribution, including the mass of the heaviest combination of equipment and attachments approved by the manufacturer, an operator of 75 kg and a full fuel tank.
6.4.2 Wheel loaders, wheel tractors, excavators and graders shall be at the manufacturer’s empty machine mass, including the mass of the heaviest combination of equipment and attachments approved by the manufacturer which produce the greatest load on the steered axle(s), an operator of 75 kg and a full fuel tank.
6.4.3 All component parameters related to steering capability shall be within the manufacturer’s specifications; i.e. tyre size and pressure, hydraulic fluid pressure and flow, warning device actuation point, etc.
7 Test procedure
See ISO 9248 for units and tolerances.
7.1 Right turn: Wheeled and articulated steer
7.1.1 Drive the machine forwards, at as low a speed as possible, on full right lock, that is, with the steering control element (e.g. steering wheel) turned to the right to its fullest extent, until the minimum diameter is being described.
7.1.2 Then continue to drive the machine forward, at as low a speed as possible, with the position of the steering control element unchanged, for a further complete turn but stopping at regular short intervals.
At appropriate stops, make projections to the surface of the test site with the plumb line and mark the test surface appropriately. The projections shall be made, as required, from the following.
a) The outermost point of the loaded (lower) section of the tyre on the vertical diameter of the outermost wheel: this point shall be used to determine the outer tyre clearance diameter.
NOTE — Should the wheel at which the measurement is being made lean outwards to a significant extent it may be advisable to determine, in addition, the outer tyre clearance diameter or radius by projecting down from the upper section of the tyre on the vertical diameter of the outermost wheel.
b) The innermost point of the loaded (lower) section of the tyre on the vertical diameter of the innermost wheel: this point shall be used to determine the inner tyre clearance diameter.
NOTE — Any inward wheel lean should again be taken into account.AS ISO 7457 pdf download.