Shearex HM-88LV front-mount mulcher

Buying width, not appetite

The HM-88LV is the coverage head in the Shearex HM front-mount mulcher range. It draws the same 178 to 288 L/min as the HM-70SV and works to the same 25 cm published target diameter, and it spends that identical hydraulic budget on 220 cm of cutting width instead of 190 cm, at 1,760 kg and a 140 hp minimum carrier. Nothing about it is built for heavier timber. Everything about it is built for covering ground.

That makes the buying question unusually clean. If the contract is measured in hectares on ground a carrier can traverse continuously, this head is the right end of the range. If the contract is measured in stems, or the material is regularly heavier than 25 cm, the HM-90SV above it is a different tool for a different problem and the extra width here will not help.

The hectare arithmetic, done properly

Width converts to area only through travel, so the sum that matters is coverage per pass rather than anything hydraulic. Two hundred and twenty centimetres is about 16 per cent more ground per pass than 190 cm on the same line of travel. On a flat site of a few hundred hectares that is a meaningful number of shifts.

But per-pass width is only one of three terms in the real rate, and the other two undo it easily on the wrong site.

• Overlap. An operator holding a 10 cm overlap loses less of a 220 cm head than of a 190 cm one in percentage terms, so the wide head’s advantage improves slightly on straight runs and evaporates on curved or obstacle-dotted ground where overlap is guessed rather than held.
• Turning and manoeuvring. Every headland turn, tree to be worked around and fence to be followed costs the same time regardless of swath, so the wider head’s advantage falls as paddock size falls. On small, broken blocks the two heads produce almost identically.
• Travel speed in the material. A wider rotor spreads the same hydraulic power over more cutting edge. On light regrowth that costs nothing; in material at the top of the 25 cm target it can mean travelling more slowly than the narrower head would, which cancels the width outright.

Because of that third term, the published optimal target material diameter of 25 cm should be read strictly here. It covers regrowth, woody weeds, wattle and light plantation residue; regular 40 cm material does not belong to this head at any travel speed, and pricing on an occasional maximum is the mistake maximum diameter versus production diameter exists to explain.

Finish class is the other half of the rate

A wide head tempts operators into chasing a fine finish with more ground contact, and that single habit multiplies dust, fuel burn and tooth wear while halving the apparent production rate. Agree the finish standard in writing before work starts, quote on hectares per productive hour at that standard, and record first and second passes separately so the client can see what a finer finish actually costs. Building a tender rate sets out how to assemble the number.

Carrier, and the transport question that follows the width

At 1,760 kg the head belongs on a dedicated mulching carrier or the very largest compact track loaders with manufacturer approval, because that mass sits ahead of the tracks and governs both stability and ground pressure on soft sites. The 140 hp published minimum is a floor rather than a comfortable operating point, for the reasons the HM-70SV page works through on this same flow window, and the circuit questions to put to a carrier supplier are set out on the HM-60 page. See also hydraulic matching, hydraulic cooling and heat and the skid steer and track loader class page for where the loader limit falls.

The consequence specific to this head is transport. At 220 cm it is wide enough to affect float width and permit requirements for the carrier and head as a combination, and on a job that involves frequent moves between blocks that recurs every time. Settle how it will be moved before the order rather than after the first mobilisation; transport and mobilisation covers the ground.

Solar sites, broadacre reclamation and fuel reduction

The work that suits it is solar and wind farm site preparation, broadacre bushfire fuel reduction and farm clearing, shelterbelts and orchards where old rows and regrowth cover large areas. All three reward continuous travel and punish the sort of site where the machine spends its day turning.

Rocky paddocks and old fence lines are the tooling risk, and a wider rotor simply meets more of them per pass, which is the argument for carbide on most broadacre work with blades reserved for clean green material; blades versus carbide teeth weighs the choice.

Where width stops paying

Width is worthless on ground the carrier cannot drive. Batters, table drains, country behind barriers and steep or wet sidling belong to an excavator head such as the VM-50SR, which shares this head’s 25 cm target and reaches what it cannot; excavator mulcher versus skid steer mulcher explains the trade. Step down to the HM-70SV where corridors are narrow, the sites are small or the carrier is lighter. Step up to the HM-90SV when 40 cm material is routine.

Tooling cost per hectare is the fair comparison

A 220 cm rotor carries more tools than a 190 cm one, so a full set costs more to refit and rock damage is spread across more holders. That makes cost per set a misleading comparison and cost per hectare the honest one, and it is the specific number to put against the HM-70SV, because the width advantage only pays if tooling cost per hectare holds as well. Ask Machinery Specialist for Australian stock and pricing on a full set, holders, belt and bearings; wear parts to price before buying lists what to request. There is one HM-88LV variant, so the remaining quotation decisions are tooling, motor build, the case drain and return arrangement, and the electrical control on the carrier’s harness.

A worked hectare estimate, illustrative only

Because this head is bought for coverage, it is worth showing how a coverage estimate is built rather than quoting a production figure, which nobody should take from a website in any case. The numbers below are round and hypothetical, and the method is the point.

Take a site of 200 hectares, flat and continuously vegetated with material inside the 25 cm target. Assume, purely for illustration, an average working travel speed of 2 km/h with the head cutting. A 220 cm swath at 2 km/h covers 2,000 × 2.2 square metres in an hour, or 4,400 square metres, which is 0.44 hectares per hour of pure cutting time. Now apply the discounts that decide the real rate: overlap between passes, headland turns, refuelling and tooling checks, and time lost to obstacles. If those together consume a third of the hour, the working rate becomes about 0.29 hectares per hour, and the 200 hectare site is roughly 690 machine hours rather than 455.

Two things follow. First, the discount factor matters far more than the swath: getting the site organised so the machine runs long straight passes is worth more than 30 cm of extra width. Second, none of this can be quoted without knowing the material and the finish class, which is why the same head returns very different rates on two sites that look alike from the road. Build the number with the method in building a tender rate, then check it against a measured sample before committing to a programme.

The second pass is where margin disappears

Most disputes on broadacre mulching are about finish rather than area, and they arise because the finish standard was described in words like tidy or clean rather than in measurable terms. Specify residual material height, whether stems must be reduced below ground level, whether windrowing or spreading is required, and how continuity is judged. Then price a second pass separately if one is wanted, because a fine finish across 200 hectares can cost as much as the knockdown did.

The operator habit that drives this is pressing the rotor into the ground to chase appearance. It doubles dust, raises fuel burn, and converts carbide into money faster than any timber does. On a wide head it also risks the skid shoes and wear edge taking the machine’s weight all day. Telling the crew what standard has been sold is the cheapest control available.

Dust, fire season and hectare-scale work

Broadacre mulching in summer is a dust and heat operation as much as a cutting one. The carrier’s screens load quickly on dry sites, oil and engine temperatures follow, and accumulated fines against hot surfaces become a fire risk in their own right. Blow down at every break rather than at the end of the shift, keep the machine’s firefighting equipment serviceable, watch for total fire ban conditions and any site restrictions, and plan the direction of travel so the discharge and the dust plume are downwind of the crew. Fire risk in clearing operations sets out what the daily routine should contain, and on solar and renewable sites the client’s own restrictions frequently go further than the statutory ones.

Ground conditions, compaction and rework

The last thing that decides whether a wide head delivers its rate is the ground it drives on. A 1,760 kg head on a heavy carrier working a wet site will rut, and ruts on a solar or agricultural site are rework for somebody, often at the contractor’s cost. Where the programme allows it, sequence the wet parts of the site for late in the season; where it does not, the cost of matting or of lost days belongs in the rate rather than in the apology. Site access, staging areas and traffic routes are worth confirming before mobilisation for the same reason; transport and mobilisation covers what a move actually involves for a machine and head of this size.

Confirm before ordering

• Block sizes and shapes in the contract pipeline, not just total hectares, since turning cancels width
• Finish class agreed in writing, with the rate built on hectares per productive hour at that standard
• Carrier meets 140 hp and its circuit holds 178 to 288 L/min continuously at pressure
• Case drain, return arrangement and motor build matched to the carrier
• 1,760 kg against the carrier's capacity, stability and ground pressure on soft sites
• Float width and permit implications of a 220 cm head on the intended carrier
• Tooling costed per hectare and compared with the HM-70SV on the same basis
• Delivered price including mounting plate, hoses and electrical harness

Frequently asked questions