Wirtgen's published range of cold milling machines covers working widths from 35 cm to 4.40 m and single-pass milling depths up to 35 cm, with three structural classes — small, compact, and large — distinguished by chassis layout, drum position, loading geometry, engine power and operating weight [S2].
Across the Wirtgen small class, milling widths step from 500 mm (W 50 R) to 1,300 mm (W 130 HR), max milling depth spans 200–300 mm, engine output sits at 100 kW (136 HP) for the 500/600 mm models and 155 kW (211 HP) at 2,300 rpm for the 1,000/1,200/1,300 mm models, and CE operating weight runs from 6,930 kg to 15,350 kg [S2].
Small Milling Machines: Rear-Loader Geometry Under 16 t
Wirtgen small milling machines use a wheeled chassis with the milling drum positioned at the rear and a height-adjustable, slewing discharge conveyor that loads directly onto waiting transport on either side, while a swivelling right rear wheel enables flush-to-edge milling against obstacles [S2]. This class is built for partial pavement rehabilitation, milling tie-ins, and floor rehabilitation inside industrial buildings, where maneuverability and one-pass truck loading matter more than daily production rate.
Model-by-model envelopes from the Wirtgen catalog place the W 50 R at 500 mm width, 210 mm max depth, 100 kW / 136 HP and 6,930 kg CE weight; the W 60 R at 600 mm / 210 mm / 100 kW / 7,450 kg; the W 100 R at 1,000 mm / 300 mm / 155 kW at 2,300 rpm / 14,700 kg; the W 120 R at 1,200 mm / 300 mm / 155 kW / 15,350 kg; the W 100 HR at 1,000 mm / 200 mm / 155 kW / 13,600 kg; and the W 130 HR at 1,300 mm / 200 mm / 155 kW / 14,100 kg [S2]. The "HR" suffix denotes a reduced-depth variant optimised for surface work rather than full-depth removal.
Compact Milling Machines: Front-Loader Balance Between Small and Large
Compact milling machines combine the maneuverability of small front-loaders with the higher power and production rate typical of the large class, and are described by Wirtgen as easy to transport and suited to confined job sites where full asphalt-layer removal is still the target [S2]. The published drum range extends the application envelope to include fine milling and layer-by-layer work, not just bulk removal.
Specific compact-class envelopes on the Wirtgen catalog page: W 100 F at 1,000 mm width, 330 mm max depth, 261 kW / 355 HP, 19,700 kg CE; W 120 F at 1,200 mm / 330 mm / 261 kW / 20,700 kg; W 130 F at 1,300 mm / 330 mm / 261 kW / 21,100 kg; and W 150 F at 1,500 mm / 330 mm / 276 kW / 375 HP / 20,900 kg [S2]. Compared with the W 100 R in the small class, the W 100 F delivers 106 kW more power, 30 mm more depth, and 5,000 kg more operating weight at the same 1,000 mm width — a useful benchmark for the "do I need a compact?" decision.
Large Milling Machines: Centred Drum, Two-Part Front Loading
Large milling machines place the milling drum centrally beneath the machine and use a two-part front-loading system with a slewing, height-adjustable discharge conveyor, with the full catalog reaching 4.40 m working width and 35 cm single-pass depth on the Wirtgen cold-milling range [S2]. This layout is engineered for high daily output on highway and runway rehabilitation, where front-loading geometry and centred mass distribution reduce truck-cycle dead time.
Within the small and compact classes, the upper published envelopes are 1,500 mm width (W 150 F), 330 mm depth, 276 kW (375 HP) and 21,100 kg CE weight — values that frame the step into the large class rather than define it [S2]. For a broader spec reference across milling, cutting and shaping equipment, the cold milling machine encyclopedia entry cross-references working-width, working-depth and power-class data used in selection.
Selection Criteria: Width, Depth, Power-to-Weight, and Drum Choice
Four decision criteria dominate cold milling machine selection: working width (must clear lane or feature width in one pass), working depth (driven by pavement layer thickness and total removal vs. milling-to-grade), engine power (which sets production rate at a given hardness), and operating weight — the latter governing transport permits, bridge ratings, and subgrade bearing pressure on weak bases [S2].
A criteria-based comparison drawn from the Wirtgen published envelopes: small-class W 50 R delivers 500 mm / 210 mm / 100 kW / 6,930 kg; mid small-class W 100 R delivers 1,000 mm / 300 mm / 155 kW / 14,700 kg; compact W 100 F delivers 1,000 mm / 330 mm / 261 kW / 19,700 kg; and the upper-end W 150 F delivers 1,500 mm / 330 mm / 276 kW / 20,900 kg [S2]. Power-to-weight ratio climbs from roughly 14.4 kW/t (W 50 R) to 13.2 kW/t (W 150 F) across this spread, a narrow band that signals Wirtgen's class-by-class scaling rather than per-model retuning. Drum options — including ECO cutters and fine milling drums — extend each chassis into fine milling, tie-in work, and surface texturing without changing the host machine class [S2].
What a Cold Milling Machine Is Not: Cold Rolling, Cold Forming, Cold Chamber
"Cold milling" in the road-paving sense is a pavement-removal process using a rotating drum fitted with tungsten carbide picks — it shares the word "cold" with several unrelated metalworking and foundry processes, which routinely causes procurement confusion [S2]. Cold rolling mills, by contrast, are metallurgical stands that reduce strip thickness at room temperature using work rolls and AGC systems, not a rotating milling drum.
The YWLX product taxonomy lists AGC systems, reversing cold rolling mills (RCM), skin pass mills, temper mills, tandem cold rolling mills (TCM), cladding rolling mills, hot-rolling production lines, water quenching devices, and related spares — none of which overlap with the Wirtgen cold milling machine class definition [S3]. For readers cross-referencing machine families on the catalog side, the core machine encyclopedia entry and the cutting machine encyclopedia entry sit on adjacent classification axes (foundry core making and discrete-part cutting) and should not be conflated with pavement cold milling. For background on the wider spec-driven process-engineering framing used across these categories, see this steel plate classification reference — the classification pattern (by width/thickness, by class, by tolerance band) is the same methodology applied to milling machines here.
Use Cases by Class, Failure Modes and Sourcing Constraints
Small-class rear-loaders (W 50 R through W 130 HR) are the right answer for partial-depth patching, tie-ins to existing asphalt, flush-to-curb work, and indoor floor rehabilitation; the swivelling rear wheel is the defining feature for edge work in this class [S2]. Compact front-loaders (W 100 F through W 150 F) bridge to full-lane asphalt removal on confined job sites where a large centred-drum machine cannot manoeuvre, and they accept the same fine-milling drum range as the rest of the catalog [S2].
Large centred-drum machines extend to 4.40 m width and 35 cm depth in a single pass, targeting highway, airport runway and full-depth concrete pavement removal where daily production rate in tonnes-per-hour dominates the bid math [S2]. Failure modes common across all three classes — and worth specifying into a purchase order — include pick loss on the milling drum, conveyor belt tracking faults on the slewing discharge, and undercarriage wear on tracked large machines (small-class machines in the Wirtgen catalog are wheeled, not tracked). Sourcing signals: published CE operating weight, declared engine power at a stated rpm, and explicit drum compatibility lists (ECO, fine milling) are the three data points most often missing from generic distributor listings and most often required by spec engineers.
Standards, Sourcing and Trackable Signals
No ISO or EN standard number is cited in the Wirtgen cold milling machine product page itself; selection is governed by job-site geometry (width, depth, daily output), transport regulations tied to CE operating weight, and emissions rules tied to engine power tier [S2]. For procurement, the trackable signals are: working width and max milling depth at declared engine power, CE operating weight for transport permitting, and the published list of compatible milling drums (ECO, fine milling) [S2].
On the metalworking side, the YWLX facility is sized for workpieces up to 4.5 m wide, 10 m long and 1.5 m high, supports 1,800 mm skin-pass mills and 1,450 mm rolling mills, and holds ISO 14000 certification — useful only as a sanity check that "cold" terminology across rolling, milling, and forming is not interchangeable [S3]. Next nodes to track: a Wirtgen cold milling machine class update expanding the published width beyond 4.40 m, a tightening of EU Stage VI engine-power bands on the compact and large classes, and a clearer published kW-to-tonne envelope for fine-milling drum configurations on small-class machines [S2].