Crane wheel assemblies for end trucks · L-block, LD, enclosed wheel-block, 45° split bearing box and European types, wheel and axle steels, tread and flange hardness and hardened depth, forged versus cast, stops and rail sweeps
A crane wheel assembly is the set of wheel, axle, bearings and housing (and, on driven wheels, a gear or reducer connection) that carries an overhead or gantry crane's end truck or trolley along its rail. Ask three things first: which assembly type fits the end truck and drive, what wheel material, tread hardness and hardened depth suit the load and duty, and how the wheels interface with the rail, stops and bumpers.
Wheel assemblies and wheel blocks for overhead, gantry and port cranes and crane trolleys, driven and idler, single- or double-flanged. Complete cranes (separate product pages), rail transfer cart and AGV drive wheels, polyurethane caster wheels and crane rails sold alone are outside this page except where compared.
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OSHA's overhead and gantry crane standard (29 CFR 1910.179) defines a truck as the unit of frame, wheels, bearings and axles that supports the bridge girders or trolleys, and the bridge as the girders, trucks, end ties, footwalks and drive mechanism that carry the trolley. [1]
DGCRANE, a crane and crane-parts maker linked to this page, describes five assembly types. An L-block assembly has a wheel axle, wheel, angular bearing box and bearings, with installation errors adjustable by hand, for heavy loads and frequent operation. An LD assembly has bearings mounted directly inside the wheel with a gear ring. An enclosed DWB wheel block has a fully enclosed housing and a ductile cast iron hub. A 45° split bearing box assembly is used for the travel mechanisms of large lifting equipment and allows easy wheel removal. A European assembly is matched directly to a three-in-one reducer without a coupling and needs high assembly precision. [2]
Editorial note: tell the supplier whether each assembly is driven or idler, how the drive connects (open gear, shaft-mounted reducer) and what bearing arrangement and wheel-change method your maintenance team expects.
Give the supplier the crane type and capacity, maximum wheel load, travel speed and duty or classification, wheel diameter and tread width, single or double flange, rail type and head width, driven or idler, drive and reducer interface, bearing type, end-truck or trolley mounting dimensions, wheel and axle material and hardness, inspection (UT, MT, hardness), environment (outdoor, explosion-proof) and quantity.
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DGCRANE lists examples by application: a European assembly with a 40CrMo axle at HB 300 and a forged 42CrMo wheel at HB 300–380; an LD assembly with a 45# steel axle at HB 217–255 and a cast 45# steel wheel at HB 300–380; a harbour portal crane assembly with tread and inner flange at HB 300–380 and hardened depth of at least 15 mm; and an RMG container gantry crane wheel in ZG340-640 with power-frequency quenching, HB ≥ 300–380 and hardened depth of at least 20 mm. It describes forged wheels as stronger and more impact-resistant but costlier, and cast wheels as cheaper but more brittle, for light-duty cranes; explosion-proof wheels are overlay-welded with stainless steel or bronze to prevent sparks. [2]
The same standard requires stops at the limits of trolley travel, fastened to resist the forces applied, and a stop engaging the wheel tread at least as high as the wheel radius; bridge trucks must have rail sweeps that extend below the top of the rail and project in front of the truck wheels. [1]
Demag's DRS and DRS-M wheel block systems show how wheel size tracks load. Its technical data for blocks with two-flange spheroidal-graphite cast iron wheels list eight sizes: DRS-M 112, 125, 160 and 200 with maximum load capacities of 2.75, 5, 7 and 10 t and block weights of 7.3, 9.9, 18.3 and 35.7 kg; and DRS 250, 315, 400 and 500 at 16, 22, 30 and 40 t, weighing 62, 117, 201 and 352 kg. The number in each name is the travel wheel diameter in mm. Demag offers four variants for connection to the customer's structure, a range of standard and special wheel shapes, and a laser alignment system for blocks on multiple travel units. [3]
Editorial calculation: a calculated maximum wheel load of 25 t exceeds the DRS 315's 22 t and falls within the DRS 400's 30 t, a 20% margin (30 ÷ 25); the wheel load itself must come from your crane's load case with trolley at the end of travel, and duty and rail checks may change the size. [3]
Editorial calculation: for a 500 mm diameter trolley wheel, a stop engaging the tread must be at least 500 / 2 = 250 mm high. The wheel size is an assumed example; check stop height whenever you change wheel diameter on an existing crane.
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Dafang Crane, a crane-wheel maker linked to this page, separates forged from cast wheel discs. Its forged route runs blanking, heating to 1200 °C, precision forging, normalising and CNC machining (stated tolerance ±0.02 mm), in 42CrMo4, AISI 4140, 41Cr4, A504, SSW-01R or 65Mn, for single-, double- or no-flange wheels on bridge and gantry cranes. Its cast route runs sand moulding, casting, annealing and surface treatment, in ZG65Mn or ductile iron, which it lists for light-duty single-girder cranes and AGV carts. [4]
The same page gives three application cases with the material and protection chosen for each environment; the table below lists them as Dafang states them. Editorial note: these are one maker's case descriptions, not limits from a standard; for any crane outside ordinary indoor service, state the minimum ambient temperature, the heat exposure, any hazardous-area zone and the required impact energy in the enquiry, and ask for the test certificates behind the supplier's figures. [4]
Editorial note: Dafang's forged/cast split agrees with DGCRANE's description above of forged wheels as stronger and more impact-resistant and cast wheels as cheaper but more brittle; name the process as well as the steel grade in the order, since the same family (for example 65Mn and ZG65Mn) can be supplied either way. [4] [2]
| Case listed by Dafang | Material and protection | Stated performance |
|---|---|---|
| 75/32 t casting crane in a furnace melting bay | KMTBCr26 alloy, 50 µm ceramic anti-oxidation layer, full forging with annealing [4] | 850 °C continuous operation; ≤0.3 % dimensional shift after 50 thermal cycles to 1200 °C [4] |
| 50 t double-girder gantry crane, 52 m span, duty A5, −40 °C | Ni-enhanced 35CrMo, 80 µm zinc plating, cryogenic tempering [4] | Charpy V-notch ≥35 J at −40 °C [4] |
| 20 t double-girder explosion-proof overhead crane, 24 m span, duty A3 | PTFE-coated insulation (≥15 MΩ) or 316L non-magnetic stainless steel, IT7 machining [4] | ATEX Ex II 2G; 500 V insulation endurance [4] |
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Listings include five types of crane wheel assembly with forged and cast wheels, port equipment wheels and horizontal wheel assemblies, and DRS-style wheel blocks and overhead and gantry crane wheel block assemblies. Ask each for wheel material, hardness, hardened depth and inspection reports.
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The last row sits on the crane rather than in the assembly, but OSHA ties stop height to the wheel radius, so it changes whenever the wheel diameter does. [1]
| Part | Role | Fix in the order |
|---|---|---|
| Wheel | Runs on the rail; tread and flange hardened. [2] | Diameter, tread, flange, steel, hardness. |
| Axle | Carries the wheel. [2] | Steel and hardness. |
| Bearings and bearing box | Support the axle; L-block, split box or in-wheel. [2] | Bearing type and housing. |
| Gear ring or reducer interface | Drives a driven wheel. [2] | Drive connection. |
| Housing (wheel block) | Encloses wheel and bearings; e.g. 7.3–352 kg blocks. [2] [3] | Mounting dimensions. |
| Stops and rail sweeps | On the crane, at the wheels. [1] | Stop height ≥ wheel radius. |
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Diameter and wheel load are linked in the Demag range, so give the calculated maximum wheel load before asking for a diameter. [3]
| Field | What it means and published values | Ask the supplier for |
|---|---|---|
| Assembly type | Examples: L-block, LD, DWB, 45° split box, European. [2] | Type and drawing. |
| Wheel diameter | e.g. 112–500 mm wheel blocks. [3] | Diameter and rail head. |
| Wheel material | Examples: 42CrMo forged; 45# cast; ZG340-640. [2] | Steel grade and process. |
| Tread hardness | Example: HB 300–380. [2] | Hardness and test report. |
| Hardened depth | Examples: ≥15 mm; ≥20 mm. [2] | Depth and method. |
| Inspection | Examples: UT and MT; hardness test. [2] | Reports to which standard. |
| Stop height | At least the wheel radius. [1] | Check for your wheel. |
| Wheel load and duty | Sets wheel size; e.g. 2.75 t at 112 mm to 40 t at 500 mm. [3] | Calculation for your crane. |
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Paste it into your enquiry below or into an email to a maker, then replace every bracket.
Crane: [type; capacity; span; duty] Wheel: [diameter; tread; flanges; driven/idler] Load: [maximum wheel load; travel speed] Rail: [type; head width] Assembly: [type; bearings; drive interface; drawing] Material: [wheel and axle steel; hardness; hardened depth] Inspection: [UT; MT; hardness reports]
DGCRANE lists five types of crane wheel assembly with forged and cast wheels; Dafang Crane lists crane wheels, DRS wheel blocks and overhead, gantry and port crane wheel block assemblies; BVEE Group lists port equipment wheels, wheel assemblies and horizontal wheel assemblies alongside sheaves and rails.
Lists five types of crane wheel assembly with forged and cast wheels.
Product scope checked 2026-10-11
Lists crane wheels, DRS wheel blocks and overhead, gantry and port crane wheel block assemblies.
Product scope checked 2026-10-11
Lists port equipment wheels, wheel assemblies and horizontal wheel assemblies with sheaves and rails.
Product scope checked 2026-10-11
Explore company information and manufacturing capabilities, then discuss the scope of your project with a relevant supplier.
DGCRANE describes L-block, LD, enclosed DWB wheel blocks, 45° split bearing box and European assemblies. [2]
DGCRANE's examples are HB 300–380 at the tread and inner flange, with hardened depths of at least 15 or 20 mm depending on application. [2]
OSHA 1910.179 requires a stop engaging the wheel tread to be at least as high as the wheel radius. [1]
Demag lists its DRS 400 wheel block (400 mm wheel) at a maximum load capacity of 30 t, from a range of 2.75 t at 112 mm to 40 t at 500 mm. [3]
Both; Dafang lists forged discs in steels such as 42CrMo4 and 65Mn for bridge and gantry cranes, and cast ZG65Mn or ductile iron discs for light-duty single-girder cranes and AGV carts. [4]
Sources checked 2026-10-12. OSHA 29 CFR 1910.179 is the US federal standard for overhead and gantry cranes; DGCRANE, Demag and Dafang are crane or crane-parts makers describing their own wheel assemblies and wheels.
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