Division 6.2Pitch

Division 6.2—Pitch

6.2.1 Type 1, Category G and Type II, Category G quad bikes are to be tested in both forward and rearward pitch directions.

6.2.2 Position the quad bike on the tilt table with each wheel centred on a load cell.

6.2.3 Align the quad bike so that a line passing through the centreline of the contact patches of the 2 downhill tyres is parallel to the line of the tilt axis of the tilt table.

6.2.4 Set the steering mechanism in the straight ahead position.

6.2.5 Apply the park brake or park mechanism, or fix the wheel or the brake assembly (if required) to stop the quad bike from rolling.

6.2.6 If the low side tyres slip on the load cell surface prior to uphill wheel lift, affix a ratchet strap over each low side wheel such that the line of action of the strap passes through the contact patch of the tyre and the axle centreline, whilst still allowing the tyre to roll about the contact patch when the vehicle tips.

6.2.7 Affix 2 catch straps (of less than 1 kg mass) between the vehicle and the tilt table with sufficient slack to allow full decompression (extension) of the uphill suspension and minimal wheel lift at tip‑over.

6.2.8 Raise the tilt table until both uphill tyres have lost contact with the ground (that is, both uphill load cells show no load).

6.2.9 Record the tilt table angle at the moment of second uphill wheel lift (tip‑over).

6.2.10 Return the tilt table to the horizontal position.

6.2.11 The static pitch‑over threshold of the vehicle in g’s of lateral acceleration (1g = acceleration due to gravity), referred to as the tilt table ratio (or TTR), is calculated as Tan of tilt table angle at 2 wheel lift (Tan Ø). The TTR is approximately equal to the static stability factor (or SSF) with variation due to CoG displacement due to vehicle body pitch and suspension articulation, compliance in steering and suspension joints and deformation of the wheels and tyres.