The complete guide to help you choose the Best Petrol Rough Cut Mowers, Completed and Edited by Real Experts in mowing tall or wild grass.

1. Introduction

Petrol rough cut mowers are specifically designed to cut very tall grass and weeds on fields and farmland. They shred the weed very finely, thus allowing the operator to leave the freshly cut residues directly on the ground. These will then decompose and become fertiliser consisting of natural organic material for the soil.

They allow the cleaning and care of soils, even those that are not perfectly levelled, performing functions similar to those of brush cutters and scythe mowers.

They are subdivided into different models depending on their cutting apparatus and functionality:

The first two categories include machines that need to be operated directly by the user thanks to the handlebars.

On the other hand, the ATV-mounted petrol rough cut mowers need to be linked to quad bikes or riding-on mowers suitable for towing such rough cut mowers. These perform the same operation as tractor-mounted flail mowers, but with more limited performance.

An alternative to the various models of petrol-driven rough cut mowers, with the same functions, are the riding-on flail mowers for uncultivated grass.

They are also used for cutting tall, weedy grass and can also operate on surfaces with steep slopes.

These are special variants of the classic riding-on mowers.

They feature powerful engines able to deliver up to 23 HP.

Like petrol rough cut mowers, they also feature large, sturdy cutting decks that can be fitted with mulching blades or cutting knives, capable of cutting through weeds, brambles, small branches and pruning residues.

2. Cutting heads

As mentioned in the introduction, the main distinction that can be made for petrol rough cut mowers is based on the different types of cutting heads fitted to the machines, each with different features and functionality.

The various models can then be further subdivided thanks to the wide choice of cutting systems available.

Petrol rough cut mowers can be subdivided into models with blade + wire cutting heads or into multi-tool models, i.e. with the possibility of mounting several cutting attachments, even those with floating blades.

2.1 Petrol rough cut mowers with blade

These machines are recommended for the maintenance and mowing of weeds in orchards and vineyards.

Their sole cutting system is the blade deck, consisting of a cutting blade that mulches the grass.

This technique shreds the grass very finely, so that it can be left to decompose directly on the working soil. Afterwards, it will turn through an entirely natural organic cycle into water and fertiliser for the soil.

In terms of operation and type of cut, they are the most similar to garden lawn mowers, yet performing completely different tasks.

In fact, lawn mowers are only suitable for cutting English lawns, and, in general, wild grass which is a few centimetres high.

2.2 Petrol rough cut mowers with blade + wire head

This category stands out for the possibility of fitting two different cutting heads: the blade plate and the wire head, both of which allow different types of cutting.

The switch between the different heads is very simple and practical, and only takes a few minutes.

As seen with petrol rough cut mowers, this type of head performs mulching cutting of tall grass.

On the other hand, the wire head is a more specific accessory, intended to perform cuts and refinings in green areas full of obstacles or rocky surfaces. In those cases, the use of the cutting deck is discouraged, since it could be damaged during the cutting operation.

Able to cut all kinds of weeds, it works just like a brush cutter, but with a much higher output.

2.3 Petrol rough cut mowers with blade head – Multi-tool

This category is equipped with the classic blade plate. It is multi-tool product because it allows several accessories to be mounted on the machine to perform many additional tasks, such as:

• Sickle bar: Suitable for mowing uncultivated grass;
• Sweeper brush: Allow to turn a flail mower into a power sweeper;
• Front brush: To brush various residues through the accessory;
• Front blade: It allows you to collect and sweep up small amounts of snow, sand and dirt.
• Snow blowers: To clear driveways and side roads from snow.
• Leaf vacuum: It allows quick collection of dry leaves;

The conversion between the different accessories is a fairly simple process, which does not take too long and can be carried out even by the less experienced users. Simply remove one accessory from the front side of the machine and insert another through the slot provided.

2.4 Heavy-duty petrol rough cut mowers with Hammers

These machines are the most professional choice, capable of delivering the best performance as well.

They mount a cutting deck with central rotor and reversible cutting hammers, which are very resistant to impact from stones and roots on the surface. They can remove not only tall, uncultivated grass, but also brushwood, brambles and pruning residues up to 2 cm in diameter.

They deliver the highest work output in their class, ensuring the finest and most homogenous shredding of grass.

These can then be divided into wheeled and tracked models, which we will analyse specifically in the next chapter.

2.5 ATV-mounted petrol rough cut mowers

The ATV-mounted petrol rough cut mowers are characterised by the same design as the flail mowers that can be mounted on an agricultural tractor. They can be attached to an ATV or a small tractor equipped with a hitch that allows them to be towed, making them a valuable alternative for those who do not own a tractor or do not need the performance of a large flail mower.

They are able to shred tall grass, small shrubs and light seedlings, while rolling the ground they pass over.

However, for their proper use and optimal performance, they require a few small precautions during their use:

• Correctly adjust the working height: Different models of ATV or riding-on mowers may have tow hooks at different heights, so it is important to ensure that the petrol rough cut mower is positioned in a sufficiently elevated position above the ground;

• Driving speed: This is arguably the most common mistake that can be made by the less experienced user. When using these machines, it is important to avoid high speeds, or sudden sprints. The speed to be kept must be constant and is the same as for tractor-driven flail mowers or versions used manually by the operator. The grass height and ground conditions also influence the speed; in fact with not too high grass, a speed between 1 and 4 km/h can be maintained, while in the case of particularly high grass it is advisable not to exceed 1-1.5 km/h.

3. Operation

As for the petrol rough cut mowers with hammers, the various models can be equipped with wheels but also with tracks.

Let’s take a closer look at the available operations and the machining processes for which they are best suited:

• Smooth wheels;
• Tractor wheels;
• Tracked;
• Paired tractor wheels;

The smooth blades allow operation on flat or gently sloping terrain.

These wheels are quite thin if compared to the other types. They allow the machine to move forward smoothly on ground with weeds of considerable height, but do not allow cutting operations on the steepest and roughest terrain.

The tractor wheels allow the machine to move forward smoothly even on uneven, sloping fields and terrain, as long as it is not too steep and the grass is very tall.

Along with these wheels, usually there are two large pivoting wheels at the front to further improve manoeuvrability and determine the precise cutting height adjustment of the machine.

Machines equipped with tracks, usually made of reinforced high-grip rubber, provide excellent grip and stability on all types of terrain, especially wet and muddy ones.

They represent one of the most versatile alternatives among all operation types.

The paired tractor wheels allow the machine a very high stability and grip on terrains with great slopes. It can easily cross terrain and surfaces not accessible with other machines.

They are made of two large pneumatic tractor wheels for agricultural operations, paired thanks to specific spacers.

4. Cutting height adjustment

The petrol rough cut mowers can also feature a cutting height adjustment system; these can be divided in:

• Single wheel: You can adjust the cutting height through the shims applied directly to the front wheels of the machine. You only need rise or lower the cutting deck to the desired position by blocking it through a small hook.
• Centralised adjustment through a single lever or knob: It is the most common; the adjustment is made through a side lever or a knob which allow to rise or lower the cutting deck height rapidly and easily.
• Pair of adjustable slides: The cutting deck height is adjusted by means of a support tube positioned directly on the cutting deck.
• Directly by the cutting deck: The user locks the cutting deck at the desired height by means of locks placed directly on the cutting apparatus.

5. Engines and power

Petrol rough cut mowers are equipped with engines produced by renowned brands of the industry, such as Honda, Briggs&Stratton, Loncin, etc. These engines can deliver excellent performance and guarantee high reliability.

Now we look in detail at the best engines for petrol rough cut mowers.

5.1 Honda

Honda engines are among the most reliable and powerful, providing high performance and medium to high power ratings.

They are now a benchmark for reliability and performance for flail mowers but also for all the machines they power.

5.2 Briggs & Stratton

Briggs & Stratton engines are American engines, completely manufactured in USA.

They guarantee a medium/high power rating for long-lasting and consistent performance.

5.3 Loncin

Loncin engines can deliver excellent performance. They are reliable and high-quality engines with very similar characteristics to other “brand” engines such as Honda or Briggs& Stratton.

They offer medium to high power and are fitted on hammer, trailed and blade models.

6. Cutting tools

Let us now take a look at the various types of cutting tools that can be mounted on the plates of the various petrol-driven rough cut mowers:

• Blade: The dish is equipped with a sturdy blade that can shred tall grass and small branches;
• Blade with floating knives: The deck consists of two load-bearing blades positioned at different heights (one lower than the other), with additional floating cutting knives at their extremities.
• Hammers: The cutting deck consists of a sturdy central rotor on which Y-shaped cutting hammers are mounted, enabling the machine to shred even brushwood and branches of considerable diameter;
• Flails: In this case, the cutting deck consists of a rotating roller where the hammer flails are mounted. Thanks to this system, not only grass and seeds are shredded, but also the turf is rolled.

7. Gears and gearbox

The number of gears that can be used on an petrol-driven rough cut mowers influences its power and user-friendliness.

Usually the smaller models with hobby use are single-speed, so they only have one gear. Models still for hobby use can also have 2 gears, one for forward and one for reverse movement.

The more powerful and heavy-duty models, on the other hand, feature multi-speed systems to allow the machines to work even on difficult and uphill areas. In the most powerful models it is mounted a 4+2 gear system, four gears for forward and two for reverse movement.

The most common gearbox among petrol rough cut mowers models is the oil-bath gearbox; however, in smaller or cheaper models we can find several variants of this type of gearbox, among them:

• Crown and worm gear grease-bath

7.1 Belt transmission

The gearbox is directly connected to the rough cut mower’s rotor through the side drive belt. It acts as a clutch in the event of overloading or impacts with foreign bodies, preventing excessive shocks and overloading.

The belt, given its fairly exposed position to possible shocks, is protected by a protective casing, optimised in size so as not to be too obtrusive during cutting operations and to allow proper belt cooling.

The thickness of the belt casing can vary from 10 to a maximum of 15 cm, thus increasing the overall width of the machine slightly.