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Quick Specs

Net Horsepower

324 HP / 242 kW @ 2000 rpm

Machine Weight

GVW: 117,892 lb / 53,475 kg


30.9 U.S. tons / 28.0 metric tons


22.4 cyd/ 17.1 m³

Maximum Travel Speed

36.4 mph / 58.6 kph


Top Features

Machine Performance

Komatsu Traction Control System (KTCS) automatically engages the inter-axle lock and modulates four independent brakes to reduce tire slipping when operating in soft ground conditions.

Tier 4 Final engine provides exceptional performance while reducing fuel consumption. Based on Komatsu proprietary technologies developed over many years, this new diesel engine reduces nitrogen oxides (NOx) by more than 80% when compared to Tier 4 Interim levels.

Keeping track of production is easier with a standard integrated Payload Meter (PLM). Loaded material weight is displayed on the LCD monitor for the truck operator and external display lamps alert the operator when the truck has reached capacity minimizing underloaded or overloaded haul cycles. Production data can be monitored through Komtrax or downloaded from the trucks controller to a personal PC.

Dual work modes allow the operator to select between Power and Economy modes to optimize the machine efficiency and performance to match the application.

Ride Performance

Viscous damper mounts are used for the cab floor mounting to reducing mechanical vibration and noise transmitted from the machine to the cab.

Large capacity, continuously cooled, wet multiple disc brakes also function as a highly responsive retarder provides the operator greater confidence at higher speeds when traveling downhill.

The front axle hydro-pneumatic suspension is a trailing arm design which allows the truck to ride smoothly. The rear-axles are mounted on a dynamic equalizer structure equipped with hydro-pneumatic suspension. The entire machine's hydro-pneumatic suspension delivers a comfortable ride and maximizes productivity.

Komatsu Quality

All major hydraulic and power train components (engine, transmission, pumps, cylinders, etc) are designed and manufactured by Komatsu which allows increased efficiency and performance.

Castings are used in high stress areas of the frame to increase durability.

Hydraulic hoses that go from the front to rear frame are supported by springs to eliminate sagging.

Operator Environment

The HM300-S's cab provides the operator with a large, quiet and pressurized work environment while providing excellent visibility during operation.

The high capacity operator's seat is equipped with an air suspension, 3-point seat belt, and is heated for added comfort. A forward facing training seat with a 3'' lap belt is located on the left of the cab and can be folded up for ease of entrance or down for access to storage.

The front dash panel provides excellent visibility to a 7'' LCD monitor and easy access to all the machine controls

A rear view monitoring system with a separate color monitor is standard for improved operator convenience.

Maintenance KOMTRAX

Every Komatsu Tier 4 Final construction machine comes standard with Komatsu CARE complimentary factory scheduled maintenance for 2,000 hours or the first 3 years, and 2 complimentary KDPF exchanges within the first 5 years. For Tier 4 Final, all Selective Catalytic Reduction (SCR) system maintenance items are covered with Komatsu CARE.

The HM300-5 has an independently driven, electronically controlled cooling fan for both the charge-air-cooler (CAC) and the radiator. Each fan can be independently reversed through the monitor panel to clean out their respective cooling cores.

The cab can be tilted rearward 32 degrees to provide easy access to the transmission and hydraulic system to simplify service. An electronically powered, hydraulic pump is now standard to tilt the cabin reducing time and effort for service.