An experimental methodology is proposed to measure the rollover propensity of road tankers when subjected to lateral perturbations derived from steering manoeuvers. The testing principle involves subjecting a scaled down sprung tank to the elimination of a lateral acceleration, to analyze its rollover propensity as a function of various vehicle's operational and design parameters. Initial acceleration is generated through putting the scaled tank on a tilt table supported by a hydraulic piston. The controlled release of the fluid in the hydraulic system generates a perturbation situation for the tank, similar to the one that a vehicle experiences when leaving a curved section of the road and going to a straight segment. Durations for the maneuver and initial tilt angles characterize both the corresponding intensities of the steering maneuver. The use of this methodology to analyze the effect of fill level, initial acceleration and tank shape on the rollover propensity of a sprung tank suggests that for high fill levels an oval tank is up to three times more prone to rollover than the circular tank, while for low fill levels such tank is up to two times less prone to rollover than the circular tank. It is suggested that the proposed methodology be used to realistically analyze the effectiveness of alternative tank shapes and slosh suppression devices, as well as suspension dimensions and characteristics.