On Saturdays, Florian Reiter, Segment Manager for Heavy-Duty Transport at MAN Truck & Bus, regularly drives an 8x4 tipper on building sites around Munich to keep in direct contact with the market. In this interview, he proudly talks about the ten-year success story behind MAN´s HydroDrive®, the first connectable hydrostatic front-axle drive.
In earlier days, the truck sector only offered a choice between a road vehicle or a vehicle with all-wheel drive. But drivers often need just a little more traction to, for instance, take the short route into a gravel pit or cope with slippery, unsurfaced ground in forested areas. And ten long years ago, MAN developed the HydroDrive® exactly for such needs, closing a gap in the market. Florian Reiter, Industrial Engineer and Segment Manager at MAN Truck & Bus, is proud of these heavy-duty vehicles. His enthusiasm for trucks is inherited from his father – who also worked in this field at MAN some twenty-five years ago.
Mr. Reiter, what is HydroDrive® and how does it work?
HydroDrive® is a connectable hydrostatic front-axle drive that can be activated by the driver via a rotary switch on the instrument panel. This system is recommended for vehicles needing added drive for a limited period - for instance on unsurfaced, slippery ground.
The HydroDrive® is made up of various components, including an hydraulic pump that is mounted on the transmission output shaft, hydraulic pipes, a cooling system and two wheel-hub drives on the front axle that power the system via the oil pressure. In this case, we´re talking about maximum system pressure of 420 bar. In constructional terms, there is a huge difference compared with all-wheel drive, which achieves this by means of a cardan shaft and a transfer case.
How is HydroDrive® used in practice?
The driver simply turns the rotary switch. This is one of the advantages compared with all-wheel drive that can only be set while standing still or when the powertrain is not loaded. HydroDrive® can be activated by the driver while cruising and also under full load.
HydroDrive® remains active up to a speed of 28 km/h and then automatically switches off. As soon as the speed drops below 23 km/h, it is automatically reactivated.
In what fields are vehicles with HydroDrive® typically used?
A typical field of application for HydroDrive® is the construction sector - tippers, tipping semitrailers, tippers with loading cranes, crane vehicles and mixer trucks. HydroDrive® is also very popular in the sector of municipal and disposal services, such as road and snow-clearing operations and for waste disposal. Vehicles used to transport timber can normally drive along surfaced roads between the sawmill and the forest, but need HydroDrive® on the tracks used to collect the wood. And another interesting segment is tank trucks and delivery vehicles. Milk-collection vehicles can then pick up milk from mountain farms, even in the winter and drivers can also deliver drinks in mountain areas. Fire-fighting, disaster control and rescue services often make use of HydroDrive®, especially in the case of roll-off systems. This allows different containers to be coupled up, depending on the place of action.
Is it also used for any less common applications?
HydroDrive® is popular in Scandinavia where there are vast expanses, snow and bitter temperatures. In these regions, the post transports its parcels in a semitrailer pulled by MAN´s HydroDrive®, making sure that it always arrives on time. Television broadcasters like Bayerische Rundfunk use semitrailer tractors for their production trailers so they can broadcast from any location, even in the winter. The wax trailer used by the German national biathlon team is also pulled by MAN´s HydroDrive®. Waxing the skis is a key basis for success and the kit managers can work in the trailer close to the athletes - more or less a rolling workshop.
What sort of customer feedback have you received on HydroDrive®?
The body manufacturers we work with are happy that, thanks to its unique design, the HydroDrive® system remains below the upper edge of the housing, as this makes it easier to adapt the bodywork. Commercial operators, such as road maintenance depots or fleet managers for instance, praise our wide range of products and have fun piecing together their vehicles without any restrictions. Drivers feel confident with HydroDrive. If they´re making their way across slippery ground in a gravel pit, then they switch on HydroDrive® and can get out again all by themselves.
HydroDrive® is lighter than all-wheel drive. What advantages does this offer?
HydroDrive® weighs about 400 kilograms less than a classic all-wheel drive. Tippers, for instance, run empty fifty percent of the time and in this case, the vehicle doesn´t have to "drag along" all the components, which saves a lot of fuel. Another bonus is that this lighter vehicle can carry an additional payload of around 400 kilograms. Which, in practical terms, means that if you have ten truckloads a day, you can transport four extra tons. This is not only good for the environment, but also hard cash.
HydroDrive® has existed for ten years. Which components have been improved meanwhile?
The greatest improvement occurred in the course of switching from the Euro 5 to the Euro 6 exhaust emission standard. In this case, we optimized the entire pipework. The hydraulic oil flows through a piping system fitted with tubes at flexible points. Now we have developed a solution that requires only a two-dimensional range of tube movement. We achieved this by decoupling the suspension from steering movements, which reduces maintenance costs even further.
MAN pioneered HydroDrive® and other competitors have followed suit. What advantages can MAN offer?
As its pioneer, we can look back on ten years´ experience. Thanks to HydroDrive®´s design, we have a decisive advantage over our competitors in that all the HydroDrive® components remain below the upper edge of the housing. This means that body manufacturers can construct their products without any problems and don´t have to adapt. We have a very wide product portfolio which means that we can offer the most popular versions of our trucks in different heights - along with the power take-offs connected to MAN´s HydroDrive®.
Do you have much to do with trucks in your spare time?
I´ve had a truck driver´s license for fifteen years. In the Volunteer Fire Service, I can make very good use of my know-how as a machinist trainer. At the same time, I drive an 8x4 tipper on a building site once a month, just to make sure I don´t lose touch with the practical side. I drive for a friend as a "real" trucker on a "real" building site. By doing this, I´m able to experience the whole range of events that occur in the course of a driver´s day - from which I do of course benefit greatly in my everyday work as Product Manager for construction vehicles. And together with my father and my brother, I also own an oldtimer, an MAN short-hood. This still makes quite an impact on the road.
Whether off-road, on construction sites or smooth roads - you can rely on MAN HydroDrive®. Experience the flexible extra drive in use.