The WR20 is the largest Trevi Benne tree shear and the one that belongs on industrial clearing and major infrastructure work where a 23 to 30 tonne excavator is already the base machine. Per-model sizing here is indicative and drawn from regional dealer literature; the factory publishes the WR family as three models spanning 1,250 to 2,225 kg, 11 to 35 tonne carriers and roughly 400 to 550 mm trunk capacity.
Where the WR20 sits in the range
The WR20 tops the heavy family above the WR15 (17 to 22 tonnes, nominal 500 mm) and the WR10 (12 to 16 tonnes, nominal 400 mm). It has no overlap with the WL Series, which ends around 21 tonnes. Its real competitor is not another shear but a different machine: at the felling hours that justify a 30 tonne carrier with a 2 tonne class head, the buyer should run the tree shear versus feller buncher comparison honestly. The tree shear buying guide frames that decision.
What the published figures mean on site
The nominal 550 mm class is the largest published capacity in the range, and on the WR20 the twin-blade Hardox system is what makes that figure reachable in hardwood rather than only in softwood: two blades each travel roughly half the section, so the cylinder force is spent on penetration rather than on crushing fibre ahead of a single edge. The practical meaning is different, though. A 550 mm green eucalypt of full height is a multi-tonne object, and the WR20’s value is that stems in the 300 to 450 mm band become routine single-stroke work with headroom to spare. Treat the 550 mm figure as headroom and sample the block as the maximum diameter versus production diameter guide describes. As the top of a family that reaches 2,225 kg, a configured WR20 with rotation, fork tower and bracket should be assumed to sit near that ceiling until the quotation says otherwise.
Carrier matching
At this size the shear is a two tonne class object before it holds anything, and the tree it holds can weigh several times that. Illustratively, assume a 30 tonne excavator rated at 6,000 kg over the side at seven metres and a configured attachment of 2,400 kg including rotation, fork tower, bracket and hitch: 3,600 kg remains for the stem. That is generous for a 400 mm hardwood tree and marginal for a tall 550 mm one, and it falls quickly on a slope or with a long stick. A 23 tonne machine at the bottom of the indicative band will have materially less. The lift chart and attachment mass guide explains how to check the over-side chart at the real radius; do it for every carrier the head might move to. Hydraulically, the auxiliary circuit must supply the cutting cylinders, the rotation motors where the 360° dual-motor option is chosen and any accumulator control, with return pressure and case drain confirmed against the current data sheet using the hydraulic matching guide.
Typical work and production considerations
The WR20 belongs on mining and pipeline corridors, solar and wind farm site preparation, large subdivision and civil clearing and plantation re-establishment, where the stem count is high, the timber is large and a 25 to 30 tonne excavator is already mobilised for earthworks. Production logic on this head is dominated by the lay-down rather than the cut: the operator cuts, rotates the stem parallel to the windrow and lowers it under control, and the time taken to do that safely with a three tonne tree is the cycle. The fork tower exists for exactly this, keeping large stems controlled through the move. The accumulator is available but only pays where a large share of the site is small regrowth mixed among the big timber. On biomass and chip-export work the placement pattern for the grapple crew is worth planning before the first cut. Dense hardwood slows cycles and shortens blade life relative to European footage, and a timed trial is the only reliable basis for a per-hectare rate.
Limitations and when to step up or down a size
There is no step up within the shear range. If stems above 550 mm are routine, the job belongs to a grapple saw or a chainsaw crew for those trees, or to a different machine entirely. Step down to the WR15 when the carrier is under 23 tonnes, when transport weight or float permits are the constraint, or when the site distribution rarely reaches 450 mm. A WR20 on a marginal carrier is slower and less safe than a WR15 on a well-matched one.
Options and configuration to settle at quotation
The family option list is on the WR10 page; what is specific here is that almost every option pushes a head that already approaches 2,225 kg further up, so each one has to be justified against the lift chart rather than ordered for completeness. Settle the rotation type, fork tower, accumulator, steep-slope pedestal, bracket and hitch, hose and coupler package, total configured weight and any counterweight recommendation in one document.
Wear parts and support
Blades, pins, bushes, seals and rotator components wear as they do across the family, with fork tower pins added. The point that matters on a WR20 is location: this head works on mining, pipeline and large civil projects a long way from a parts counter, so confirm Australian stock and lead time and keep a blade set and a pin and bush kit on site. The wear parts guide has the full list.
Confirm before ordering
- That the 23 to 30 tonne and 550 mm figures are indicative and the quotation carries the current factory data sheet
- Configured weight with rotation, fork tower, accumulator, pedestal, bracket and hitch, and any counterweight recommendation
- Over-side lift-chart values at the working radius on every carrier the head may be fitted to
- Flow, pressure, rotation circuit, return pressure and case drain against the data sheet
- Fork tower specification and whether it is standard or optional on the WR20
- Transport weight and float permit implications with the head fitted
- Blade, pin and bush pricing, Australian stock and lead time for remote projects
- A timed trial in large Australian hardwood before per-hectare rates are set
- Comparison against a feller buncher if annual felling hours are high
Frequently asked questions
Is the WR20 a factory-rated 550 mm shear?
The factory publishes the WR family at roughly 400 to 550 mm. The WR20 as the largest model sits at the top of that span; the 23 to 30 tonne pairing is indicative dealer sizing. Get the current data sheet with the quotation.
Can a 23 tonne excavator run a WR20 properly?
It is at the bottom of the indicative band. The lift chart at your working radius, the stick length and the ground slope decide whether the head is usable at reach. Ask for a written compatibility assessment for that machine.
When does a feller buncher beat the WR20?
When felling hours are high enough and the work is consistent enough to justify a dedicated forestry carrier. When the excavator digs between clearing stages, the shear usually wins on utilisation.
Do I need the fork tower?
If large stems are routine, yes, because it keeps the tree controlled during the move. On mixed sites with mostly medium stems it is extra mass.
What happens to stems bigger than 550 mm?
Handle them separately with a grapple saw or chainsaw crew. Do not size the whole fleet around the largest one per cent of trees.
Other tree shears to compare
Trevi Benne WL Series tree shears
The compact and mid-size end of the current Trevi Benne range: three models spanning 2.5 to 21 tonne excavators, with optional rotation and an upper accumulator for bunching small stems.
Trevi Benne WR10 tree shear
The entry point to the heavy WR family. Indicatively matched to 12 to 16 tonne excavators with a nominal 400 mm cutting class, twin-blade architecture and hydraulic rotation options.
Trevi Benne WR15 tree shear
The mid-range WR shear for the 17 to 22 tonne excavator class that most civil and clearing contractors already run, with a nominal 500 mm cutting class.
Get a recommendation, not just a price
Send us your excavator model, hydraulic figures, tree species and typical diameters. We will come back with a carrier-matched configuration and a written specification you can compare against any other quote.