Home > CTM3–CTM14 Concrete Mixer Drum (Upper Part) — TRUEMAX Drum Range

CTM3–CTM14 Concrete Mixer Drum (Upper Part) — TRUEMAX Drum Range

The CTM is the TRUEMAX concrete mixer truck upper part — the drum, sub-frame, hydraulic drive, water system and discharge chute that mounts onto the chassis. Seven drum sizes are offered, from the CTM3 with a 4.45 m³ geometric drum at the small end of the range up to the CTM14 with a 20.4 m³ geometric drum at the top. Across the whole range the engineering is the same: a wet-mix drum built from 520JJ wear-resistant steel for both the drum and the mixing blades, driven by an Eaton/PMP hydraulic pump and motor, cooled by a KT-18 radiator, with an air-pump water supply system. What changes between models is what should change: the drum's geometric volume and rated payload, the inclination angle, the padding rate, and — at the upper end of the range — the reducer choice and the water-tank capacity, each scaled to the duty cycle the drum is built for.

The CTM range pairs with three TRUEMAX chassis options to make a complete concrete mixer truck. The CTM3 is matched with the light SINOTRUK-HOWO 7 chassis for 3–5 m³ city work; CTM6, CTM8, CTM9, CTM10 and CTM14 pair with the mainstream SINOTRUK chassis (6×4 or 8×4); and the CTM12 is the standard match for both the mainstream SINOTRUK 8×4 and the flagship SINOTRUK-HOWO N7 Euro V. The complete vehicle — chassis plus matched upper part — is built up and tested at the TRUEMAX factory in Haining to ISO 9001:2015 and CE standards, supplied with the full one-stop after-sales programme: three-minute service response, 24-hour solutions, and a remote intelligent service and self-diagnosis system across a working line exported to more than 120 countries.

1. 520JJ wear-plate drum and blades across the whole range — Drum shell and mixing blades on every CTM model are made from 520JJ high-wear-resistance steel — the same grade from the smallest 4.45 m³ drum to the largest 20.4 m³, so service life is consistent across the fleet and parts inventory is simplified.

2. Eaton or PMP hydraulic pump and motor, every model — The drum is driven by a hydraulic pump and motor pair from Eaton or PMP across all seven CTM models. Eaton and PMP are both globally serviced brands, which keeps drum-drive maintenance reliable in any export market.

3. Bonfiglioli/PMP reducer on CTM8 and above; Lead374 on CTM3 and CTM6 — Two reducer options matched to drum size. The smaller CTM3 and CTM6 use the Lead374 reducer — sized correctly to their load. The CTM8, CTM9, CTM10, CTM12 and CTM14 step up to the Italian Bonfiglioli reducer (or PMP) for the higher torque and longer service life the larger drums need.

4. Geometric drum volumes from 4.45 m³ to 20.4 m³ — Seven drum sizes cover the entire mainstream payload range. The geometric volume (drum interior capacity) is larger than the rated payload — for example, the CTM12 has an 18.4 m³ geometric drum carrying 12 m³ of concrete — because concrete needs head room for mixing and the residual material that stays in the drum between loads.

5. Wet-mix drums across the range — Every CTM drum is configured for wet mixing — the standard for ready-mix concrete delivery, where the batching plant produces complete concrete and the drum mixes and holds it on the road. The TRUEMAX brochure does not offer dry-batch (transit-mix) configuration in the CTM range.

6. 50–210 mm slump compatibility — All seven drums are built to handle concrete from 50 mm slump (stiff, low-water structural concrete) up to 210 mm slump (high-flow, pumpable concrete) — the full practical range commercial RMC operators encounter.

7. Air-pump water supply with 240–1,000 L tank — An air-pressure water system supplies wash and mix water without an electric pump. Tank capacity is sized to drum size — 240 L on CTM3/CTM6/CTM8, 350 L on CTM9/CTM10, and 450 or 1,000 L on CTM12/CTM14 (operator's choice) — for cleaning down between loads and adding adjustment water at the pour.

8. KT-18 oil cooling and one-stop service — KT-18 oil-cooling radiator on every model keeps the hydraulic system within working temperature on long shifts. Pre-sale tailored chassis-and-drum configuration, on-site commissioning of the complete vehicle, driver and operator training, three-minute service response, 24-hour solutions, and a remote intelligent service with self-diagnosis through working life.

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Technial Parameters

Model	CTM3	CTM6	CTM8	CTM9	CTM10	CTM12	CTM14
Drum & Mixing Geometry
Mixing Type	Wet	Wet	Wet	Wet	Wet	Wet	Wet
Geometric Volume of Drum (m³)	4.45	9.6	11.8	14.4	14.4	18.4	20.4
Drum & Blade Material	520JJ	520JJ	520JJ	520JJ	520JJ	520JJ	520JJ
Inclination Angle for Drum (°)	16	15	16	13	13.5	12	12
Padding Rate (%)	67.4	63.8	67.8	62.5	69.4	65.2	68.6
Residual Rate (%)	<0.2	<0.2	<0.2	<0.2	<0.2	<0.2	<0.2
Charging / Discharging / Mixing
Charging Speed (m³/min)	≥3	≥3	≥3	≥3	≥3	≥3	≥3
Discharging Speed (m³/min)	>1	>1	>1	>1	>1	>1	>1
Mixing Speed (r/min)	0–14	0–14	0–14	0–14	0–14	0–14	2–14
Slump Range (mm)	50–210	50–210	50–210	50–210	50–210	50–210	50–210
Hydraulic & Drive Components
Hydraulic Pump	Eaton/PMP	Eaton/PMP	Eaton/PMP	Eaton/PMP	Eaton/PMP	Eaton/PMP	Eaton/PMP
Hydraulic Motor	Eaton/PMP	Eaton/PMP	Eaton/PMP	Eaton/PMP	Eaton/PMP	Eaton/PMP	Eaton/PMP
Reducer	Lead374	Lead374	Bonfiglioli / PMP	Bonfiglioli / PMP	Bonfiglioli / PMP	Bonfiglioli / PMP	Bonfiglioli / PMP
Radiator	KT-18	KT-18	KT-18	KT-18	KT-18	KT-18	KT-18
Water System
Water Tank Capacity (L)	240	240	240	350	350	450 / 1000	450 / 1000
Water Supply	Air pump	Air pump	Air pump	Air pump	Air pump	Air pump	Air pump

Dimensions & Working Range

Three drum-geometry parameters scale across the CTM range. The drum's inclination angle steps from 16° on the smallest CTM3 down to 12° on the largest CTM12 and CTM14 — flatter drum on the larger sizes for more efficient discharge of the bigger load. The padding rate (ratio of rated payload to drum geometric volume, expressed as a percentage) is optimised per model — between 62.5% and 69.4% — to balance mixing quality against drum economy. Charging speed of at least 3 m³/min and discharging speed above 1 m³/min are held across every drum. Read the drum cross-section against the chassis dimensional drawing when planning batching-plant loading geometry and on-site discharge clearances.

A complete TRUEMAX mixer truck is sold as one vehicle — chassis plus matched CTM drum — built up and tested at the TRUEMAX works. The three chassis pages document each lower-part option in detail; the table below shows the natural pairing of each chassis with the CTM drums it carries.

CTM3 with SINOTRUK-HOWO 7 (Light)

The CTM3 (4.45 m³ geometric drum, 3 m³ rated payload, 240 L water tank, Lead374 reducer) is the city-truck drum, matched with the SINOTRUK-HOWO 7 4×2 light chassis (Yuchai 102 kW, Euro II). Together they form the 6.7 m compact mixer truck for narrow streets, weight-restricted bridges and small ready-mix operations.

CTM6, CTM8, CTM9, CTM10, CTM14 with mainstream SINOTRUK

These drums sit in the mainstream payload band — 6 to 14 m³ rated. They pair with the SINOTRUK ZZ1257 6×4 chassis (CTM6 to CTM10) or the SINOTRUK ZZ1317 8×4 chassis (CTM10 to CTM14), depending on drum size and axle-load regulations in the destination market. The mainstream SINOTRUK chassis is offered with the Weichai WP10 engine at 340 kW or 380 kW in any Euro II to Euro V emission band.

CTM12 with mainstream SINOTRUK 8×4 or with SINOTRUK-HOWO N7

The CTM12 (18.4 m³ geometric drum, 12 m³ rated payload, 450 or 1,000 L water tank, Bonfiglioli reducer) is the only CTM drum that pairs with both the mainstream 8×4 (Euro II to Euro V) and the flagship SINOTRUK-HOWO N7 (Euro V single-spec, MC11 440 kW, 100 km/h motorway-grade). The choice between them is regulatory environment (Euro V required or not) and route profile (long-distance motorway running or not).

Applications

Concrete mixer trucks deliver ready-mix concrete from the batching plant to the pour, mixing on the road to keep the concrete homogeneous and workable until discharge. The CTM range covers the full payload band these deliveries are sized to.

Commercial ready-mix (RMC) supply

Commercial RMC fleets serve a mix of small, mid-size and large customers across a city or region. The CTM6 to CTM10 drum sizes are the workhorse of typical RMC fleets; CTM3 handles small downtown pours; CTM12 and CTM14 cover the largest mass-pours and busy commercial sites.

Concrete delivery for major projects

Major motorway, bridge, port, airport and high-rise construction draws on the larger drums — CTM10, CTM12 and CTM14 — for continuous high-volume supply. The 50–210 mm slump compatibility covers the structural, pavement and pumped concrete these projects need.

Precast and on-site concrete delivery

Precast yards and on-site concrete operations use mixer trucks both for inbound transit and on-site shuttling between batching plant and forms. The wet-mix CTM drum range is sized to either duty.

Project-specific drum sizing

On projects with restricted access or specific axle-load rules, the drum is sized to fit. A 3 m³ drum on city access; a 6–8 m³ on suburban; 10–14 m³ on motorway-served sites. TRUEMAX configures the chassis-and-drum pairing to your project, not the other way round.

FAQs

What is the difference between geometric volume and rated payload?

Geometric volume is the drum's interior capacity; rated payload is the volume of concrete the drum is rated to carry. They differ because concrete needs head room to mix in the drum without overflowing, and a small residual stays in the drum between loads. For example the CTM12 has an 18.4 m³ geometric drum carrying 12 m³ of concrete — the model number is the payload, which is what you sell to your customer. Padding rate (62.5% – 69.4% across the CTM range) is the ratio of payload to geometric volume.

Why does the CTM14 have a 2–14 r/min mixing speed when every other drum runs 0–14?

Honest answer: at 20.4 m³ geometric and 14 m³ payload, a stopped drum risks the concrete segregating — the heavier aggregates settling while the cement paste rises. The smaller drums can fully stop between operations because their concrete settles less in the short stops typical of a delivery cycle. The CTM14 specifies a 2 r/min minimum to keep the drum turning slowly even at rest, which holds the concrete homogeneous through a longer delivery.

Why two reducers — Lead374 on the small drums, Bonfiglioli/PMP on the large?

Torque and service life. The Lead374 reducer is correctly sized to the lighter loads of the CTM3 (3 m³) and CTM6 (6 m³) drums. From the CTM8 (8 m³) upward, the drum torque demand steps up significantly, and TRUEMAX specifies the Italian Bonfiglioli reducer (or PMP) for the higher torque rating and longer service life the larger drums need. Both are reliable choices for their respective drum sizes; the spec reflects the load.

Is 520JJ steel the same as the standard mixer-truck drum steel?

520JJ is one of the high-tensile, abrasion-resistant steels used industry-wide for concrete-contact surfaces — drum shells and mixing blades. The grade has higher hardness than ordinary low-alloy structural steel, which extends the service life of the drum against concrete abrasion. Some manufacturers use comparable grades like Hardox or domestic equivalents; TRUEMAX specifies 520JJ across the whole CTM range for consistency.

What slump range can the drums handle?

Every CTM model handles 50 mm to 210 mm slump — from stiff low-water structural and pavement concrete (50–80 mm slump) through general construction concrete (100–150 mm) to high-flow pumpable concrete (150–210 mm). This covers virtually all ready-mix product menus.

Why is the water supply driven by an air pump rather than an electric pump?

Simplicity and reliability. An air-pressure water-supply system uses compressed air from the chassis's air system to push water from the tank — no separate electric motor, no electrical seal points exposed to wet conditions, and minimal moving parts. It works whenever the chassis's air system is up, which is whenever the engine is running. Electric water pumps are more sensitive to wet-environment service issues.

Can a CTM drum be retrofitted to a non-TRUEMAX chassis?

The CTM is engineered as part of a complete TRUEMAX vehicle (chassis + sub-frame + drum + hydraulics + water tank + chute), built up and tested at the TRUEMAX factory. Retrofit to another chassis is not the standard supply route. If your project needs a CTM drum on a specific chassis brand not currently offered, TRUEMAX can quote the build on request — tell us the chassis make, model and intended drum size and we will confirm feasibility.

Which CTM drum and which chassis should I specify?

Pick drum size by pour-rate and trip-volume needs. CTM3 for 3 m³ small-pour and city delivery; CTM6 to CTM10 for general RMC and construction; CTM12 for high-volume commercial supply and major projects; CTM14 for the largest payload duty cycles. Then match the chassis to the drum: HOWO 7 for CTM3; mainstream SINOTRUK 6×4 or 8×4 for CTM6 to CTM10 and CTM14; mainstream SINOTRUK 8×4 or HOWO N7 (Euro V) for CTM12. The three chassis pages document the chassis side in detail.

Why the CTM range is built as one upper-part platform

Across seven drum sizes the CTM range shares one engineering platform: 520JJ wear-plate drum and blades, Eaton/PMP hydraulic pump and motor, KT-18 radiator, air-pump water supply, wet-mix configuration, 50–210 mm slump compatibility. Two things scale with drum size — the reducer (Lead374 on small drums, Bonfiglioli/PMP on large) and the water-tank capacity (240 to 1,000 L). The result for fleet operators is real: drivers learn one set of controls regardless of drum size, the parts inventory shares the major hydraulic and cooling components, and service technicians work on one platform across the fleet.

How the drum's geometry shapes delivery

Three drum parameters together determine how a mixer truck works in service. Inclination angle (16° on small drums down to 12° on large) — flatter on bigger drums for faster discharge of bigger loads. Padding rate (62–69%) — the percentage of geometric volume used as rated payload, optimised per model. And mixing speed (0–14 r/min on most drums, 2–14 on CTM14) — controls how vigorously the drum stirs the concrete in transit. Operators do not normally adjust these — they are engineered into the drum — but understanding them helps explain why a 14 m³ drum is not just a bigger version of a 12 m³ drum.

Choosing within the CTM range

Drum-size choice is driven by three things in roughly this order. First, the pour-volume profile: a fleet whose typical pour needs 12 m³ delivered per trip cannot do that with a CTM6 (which would force two trips and twice the haul time). Second, route access — if the destination is a downtown street with weight-restricted access, the largest drum that can legally reach it might be a CTM3 on the HOWO 7. Third, regulatory environment — Euro V destination markets pair the CTM12 with the HOWO N7 flagship chassis, while Euro II destinations stay with the mainstream platform. TRUEMAX configures the drum-and-chassis pairing to your project; tell us pour profile, access constraints and destination market and we will recommend the match.