Heir to the Krone: what does the all-new Big M 450 have to offer?

The new Big M 450 is continuing with the original Big M mower concept, but this impressive machine is fully redesigned from scratch. It boasts a large number of standout design features including a new cab, a new engine, a new running gear and redesigned mower units. With a maximum cutting width of 9.95m, Krone claims that the new model offers the potential of achieving work rates of up to 17ha/hour.

Mowers

The overall working width of the machine has increased. The Big M 420 currently on the market has a cutting width of 9.7m, while the new Big M 450 has a cutting width of 9.95m. New to the 450 model is an extra disc on each of the side mowers. There are seven discs on the front mower, while there are eight discs on each of the side mowers.

The new Big M 450 sits on a redesigned frame. Krone has changed the rear axle on the 420 model to a higher rounded axle on the new 450 model which can be seen in the picture above.

The three mowers are powered directly from the engine via power bands and driveshafts. Each mower is powered directly from the engine, so there are no power losses. The front mower has a cutting width of 3.16m. It has a split driveline for a perfect balance. The front mower also has an angle-dependent lateral displacement. This is the automatic shifting of the front mower to either side to follow any sloping ground and avoid leaving strips of grass. This displacement can also be adjusted manually. Cutting height is adjusted hydraulically from the cab for ease of operation.

The side mowers have a cutting width of 3.6m. The attachment of these mowers has been completely redesigned. Krone has used their unique DuoGrip centre of gravity suspension and link arm-controlled design. This allows for uniform ground pressure and a perfect cut across the full working width, even on slopes and verges.

The side mowers have a completely new breakaway system. In the case of the side mower coming into contact with an object other than grass, the mower will lift up and move back. This new system will provide the operator with more peace of mind.

The 64cm diameter high-performance conditioner with V-type steel tines is the largest in the industry. Due to the conditioner size, less rotations are required, meaning it is more gentle on the crop. The V-type tine conditioners on the side mowers are now single-piece, which eliminates the central drive unit and positions the PTO shaft and gearbox on the side. This results in a more uniform crop flow and reduced input power for increased productivity.

Krone is now using Hardox plates as standard, which are bolted on to the walls of the augers. Now users just have to replace theses Hardox plates and not the whole auger as was necessary in the past.

There is an option of either 700rpm or 1,000rpm conditioner speeds. This can be easily adjusted without any tools on the input gearbox on the side of the machine. The space between the cutterbar and the deck has been increased by 20% to allow for increased throughputs and enhanced crop flow.

All mowers are equipped with Krone’s SafeCut and SmartCut systems. The SafeCut system works via a roll pin which breaks when the disc is exposed to an overload such as foreign objects. The SmartCut system was designed for a perfect clean cut. Discs turning outwards have different diameters for larger overlaps to avoid striping.

Engine

Krone’s previous Big M mowers have been fitted with John Deere, Caterpillar and Mann engines. The new Big M 450 model is powered by a Stage 4-compliant 12-litre 449hp Liebherr engine. This engine offers an extended 1,500-hour service interval compared with the previous 500-hour service interval on the 420 model. The monstrous 449hp engine equates to 45hp per metre working width. A point to note is that this engine isn’t completely different from the Mann engine used in the current 420 model because Mann uses a Liebherr block while building its engines.

The engine and gearbox are placed on silent blocks which absorb any vibrations, which allow for quieter operation. Two silent blocks can be seen in the picture above.

To coincide with the mammoth engine power, the cooling system has also been updated.

The radiator in the new 450 model is similar to that in the 420 model, but it is located higher to avoid the same level of dust intake.

Auto engine control has been added as a new feature. This automatically switches between Eco Mode and M Mode to supply just the right engine output to match the current demand. The machine is set to run in Eco Power at 260kW (354hp) and this will automatically increase to the maximum 449hp if the extra power is required. The objective of this is to be more efficient by reducing fuel consumption and it also allows the machine to run quieter when possible.

The Big M 450 model comprises automatic top-speed control as standard. This new design automatically reduces ground speed when the engine drops below 850rpm. It allows for efficient machine utilisation and eliminates the possibility of blockage, warranting a perfect cut. The engine and gearbox are placed on silent blocks which absorb any vibrations, in turn allowing for quieter operation.

Chassis

The new Big M 450 sits on a redesigned frame. The axles rest on four hydraulic rams. This provides hydro-pneumatic suspension on both the front and rear axle. These rams also act as springs. The axles will automatically lower for road transport to a total machine height of 4m.

In field mode, the axles will automatically be raised by 15cm. Krone has changed the rear axle on the 420 model to a higher rounded axle on the new 450 model. The purpose of this is to provide the machine with greater ground clearance. This may be desirable where operators are grouping heavy crops of grass into a single ledge.

Silentspace cab

The SilentSpace cab is new to the Big M mower series. It has been adapted from Krone’s line of self-propelled Big X forage harvesters. This cab contains a high-resolution 10in touchscreen monitor with colour display. The cab inside has increased vision through a wider cab and slimmer corner posts. The simple modern layout inside makes the machine very user-friendly.

The optional LED lighting package provides superb 360-degree visibility while working at night. Optional LED lights on the steps and on all service points allow for increased visibility. An optional reversing camera can also be fitted with a display screen.

Ground drive

The new Big M 450 runs on Bosch Rexroth wheel motors. These wheel motors are also used in the Big X forage harvester line. They allow the machine to travel at a speed of 40km/hour at just 1,250rpm. While in field mode, these motors will run at a speed of up to 25km/hour, while mowing at 1,650rpm. The objective behind this is to reduce fuel consumption and provide a smoother ride for the operator. The Big M 450 model will be distributed across Europe with 4WD as standard.

The 450 model will come as standard on low ground pressure Mitas tyres; on the front are 800/65/R32 while on the rear are 600/65/R28 tyres. For an increased footprint, wider Vredestein flotation tyres are an optional extra.

Augers

Krone explained that 99% of Big M users worldwide have augers (swathers) on their side mowers. Krone is now using Hardox plates as standard which are bolted on to the walls of the augers. This provides for cheaper repair. Now users just have to replace theses hardox plates and not the whole auger as was necessary in the past.

Independent auger control provides operators with the choice of grouping from one mower and not the other.

Service and maintenance

The size of the fuel tank has increased to 780 litres, plus an additional 80-litre storage for AdBlue. Auto lubrication on the machine is sensor-monitored with an 8kg capacity, which will cover a number of days’ work. There are nine grease points on the machine which must be greased after 100 hours of use.

Accessibility was another factor Krone looked at while redesigning this machine. From opening one panel nearest the engine, operators have access to air and oil filters, the oil dipstick and the oil reservoir.