12 four-disc saw heads for a customer near Kaunas in Lithuania

In February 2026, 12 ROLMEX four-disc saw heads were delivered to the area of Kaunas in Lithuania. The buyer is one of the largest purchasers of municipal machinery on that market, and the heads are to work on infrastructure and green area maintenance. An order on this scale is a good moment to explain what a road authority needs a disc saw on a power arm for, and how it is matched to a specific job.

What the delivery covered

• 12 disc saw heads in the four-disc version,
• four independent hydraulic motors in each head,
• buyer: one of the largest buyers of municipal machinery in Lithuania,
• destination: the area of Kaunas,
• scope of work: infrastructure and green area maintenance.

Why a road authority needs a disc saw on an arm

The typical job for a saw hung on an arm is maintaining the clearance envelope. Branches reaching over the carriageway, hiding signs or brushing against vehicles have to be cut off cleanly, several metres up. The TR series data sheet describes this application directly: the head is used for pruning and cutting branches from the machine’s arm — in the road right-of-way, on slopes, along fences and in wooded areas — without the operator leaving the cab.

In the TR series of disc saws the product data sheet gives working widths from 1300 mm (TR130) to 2000 mm (TR200) and a maximum diameter of cut material of 120 or 150 mm, depending on the model. The discs are 600–650 mm in diameter. Another point of practical importance is the variable head attack angle of up to 15˚, which allows the cutting plane to be matched to the line of the tree crowns or the fence, instead of sawing in steps.

When a saw, and when a cutterbar

The disc saw performs well in pruning and cutting in the crowns. For clearing brush on verges and ditches at ground level, the more common choice is the TGR-155 cutterbar: 1550 mm of working width, a maximum diameter of cut material of 120 mm, head rotation of 180˚-235˚ and a weight of 240 kg. Its data sheet gives an output of 0.2 – 0.7 km/h and requires a creeper gear in the tractor — figures worth putting into the schedule before the kilometres for the season are planned.

The number of motors in a disc head

The number of hydraulic motors is not a marketing parameter but a design decision about the way the drive is transmitted. The ROLMEX catalogue shows this on the example of the TR series: TR130 works on two motors in the V-belt version, TR155 and TR165 on three motors in the maintenance-free version — with no belts, chains or lubrication system — TR180 on three motors in the maintenance-free version or with V-belts, and TR200 comes in a variant with two or four hydraulic motors, in the V-belt version or with hydraulic drive.

For the user this means fewer parts wearing out in the field. The manufacturer indicates that the patented hydraulic system free of V-belts provides greater reliability and a lower risk of failure, and that the dry-break valve system protects against oil loss. In a maintenance fleet working in the traffic lane, every component less to tension and lubricate is one item less in the seasonal inspection.

The carrier decides how far the head will reach

The head is hydraulically driven, so — as the TR series data sheet states — the match is decided by the way it is mounted on the arm and by the output of the carrier’s hydraulic system. The reach of the arm, in turn, settles how wide a strip one pass will cover, and the data sheets give specific minimum values for it. The KR POWER series power arm mowers are the KR-520 with a reach of 5.6 m (required power 100 HP, minimum tractor width 200 cm, minimum weight 4000 kg) and the KR-600 with a reach of 6.5 m (110 HP, 220 cm, 4500 kg). The power of both arms is 68 HP.

When the reach has to be changed during the pass — a narrow verge at one moment, the counter-slope of a wide ditch at the next — the choice is the KR-Z POWER series with a telescopic second arm: the KR-600Z reaches 6.4 m and requires a 110 HP tractor with a minimum weight of 4500 kg, the KR-700Z reaches 7.5 m with requirements of 130 HP and 5000 kg. Both arms have their own hydraulic system with a 220/240 litre tank and an oil cooler that cuts in at 45˚C, which matters in all-day work with a cutting head.

What to check before requesting a quotation

• the make, model, power, weight and width of the tractor — they determine the permissible arm reach,
• the way the head is mounted at the end of the arm and the output of the carrier’s hydraulics,
• the cross-section of the material on the sections to be maintained — whether it falls within the 120 or the 150 mm range,
• the share of work in tree crowns compared with brush clearing at ground level, because this settles the choice between a disc saw and a cutterbar.

In a delivery such as this one near Kaunas, covering more than a dozen identical heads, what counts is not the individual machine but the compatibility of all the heads with the arms they are to work on. That is why the selection starts from the carrier data, not from the name of the head model.