The visibility is also excellent, and ensured by the side portholes on the doors, which are very useful when engaged in off-road journeys or negotiating chaotic city traffic. There are also very broad rear view mirrors which, on request, can also be heated and electrically adjustable. The cab suspension is still of the 4 point mechanical version and thanks to the possibility of adjusting before loading, one can customize performance based on the different uses to which the vehicles is being put. The novelty consists in the new reinforcements beneath the bodywork and new hitching points with movement adjusters designed so that the operation of the suspensions can be optimized and lateral oscillations reduced to a minimum.
The entire kinematic chain has been studied to handle the most taxing missions: the 8 and 13 litre Cursor engines with electronically managed pump injectors and double overhead camshaft, thanks to the exceptional torque specifications at the various engine speeds and the engine brake, guarantee the HD9 a highly versatile on road performance and exceptional braking power, the most essential features when operating on site. Astra also offers a wide range of choice between mechanical gearboxes with Ecosplit 4 technology (ZF with 16 speeds), automated Astronic 16 speed boxes and Allison automated versions for a maximum performance of the engine in terms of peak power and an excellent traction on all types of terrain.
Depending on the load, the Astra offers the option of equipping its vehicles with front axles and motor axles bearing loads of 8t, 8.5t, 9t and even offers a reinforced version with the a load bearing capacity of 10t on 6x6 and 8x6 motorised axle models, designed for particularly tough use, on terrain such as sand or mud; or with special set ups with loads concentrated on the front axle such as tow systems, cranes or boring structures.
The real strong point of the Astra vehicles is its chassis, built out of special steel with the highest level of resistance and high elasticity thanks to the two flat beams running parallel to each other for the entire length with a C section (320 x 90 x 10mm) and joined to each other by crosspieces.
With the highest Rail Bending Moment (R.B.M.) among competing vehicles, the Astra chassis is renowned for its capacity to transport heavy loads on any ground condition reducing torsional stress and ensuring great stability even with high centres of gravity. Its extremely "streamlined" structure, which, owing to its sturdiness does not require any reinforcements, means any superstructure can easily and quickly be mounted on it. Die cast leaf spring supports and trailer backs designed with very high safety coefficients, enable quality levels to be attained which place these vehicles at the top end of their category.
As far as suspensions are concerned, the vehicles within the HD9 range are equipped with parabolic type leaf spring supports which have been installed on both front and rear axles, for increased comfort and noise reduction. For specific set ups with very high centres of gravity and for extreme usage conditions one can fit semi-elliptical leaf spring suspensions on request.
The HD9 range is equipped with drum brakes with two rotating chambers (Duo Duplex) for each wheel, to balance the braking better and make wear on the gaskets more uniform and consequently extend their duration. The braking system is very orderly and clean thanks to the use of the APU's (Air Processing Unit) which, in a single unit, also encompass a number of valves. The brake correction is guaranteed by the EBL system (Electronic Brake Limitation) and by the ABS system which electronically manages, wheel by wheel and instant by instant the ideal brake distribution, without risk of seizing regardless of the kind of load being transported.