Komatsu D31PX-21 KOMSTAT II Crawler
Series: Other models
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Komatsu mining – other models: the collective page of dozers and mining machines outside the named ranges, from the D20 to the D155AX, the haul trucks 730E to 980E and the Joy underground machines 12CM and 14CM
This page gathers the Komatsu machines of the mining and crawler group the register could not assign to a named range – above all dozers, plus haul trucks and the underground machines Komatsu took over in 2017 with Joy Global. Komatsu of Tokyo, founded in 1921 in the city of Komatsu, built Japan's first dozer in 1943 and is today the world's second-largest construction-equipment maker after Caterpillar. The type logic of the dozers: D marks the dozer, the number the size class – D20 and D21 the small dozers around 4 t, D65 the mid-range, D155 and D375 the big ones, D475 the mining dozer – A the standard version, P the swamp dozer with wide tracks (D20P), PL and PLL versions with long undercarriage, X and AX the generations since the 1990s, -2 to -8 the upgrades, E the version with emission stage. The haul trucks 730E to 980E are electric-drive mining trucks with 190 to 400 tonnes payload, the 12CM and 14CM continuous miners for underground coal mining. The engines are Komatsu's own 4D95, 6D105, 6D125 and 6D140 series in the dozers and the SDA12V and SSDA16V engines of up to 46 litres in the trucks.
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The register lists here 334 versions with 26.1 to 857.6 kW from four- to twelve-cylinders of 1,101 to 46,300 cm³, torque from 147 to 3,322 Nm at 1,600 to 2,500 rpm and operating weights up to 175,500 kg.
Komatsu's dozers are, alongside Caterpillar's, the reference of the class; the D155 and D375 are the standard machines of open-cast mining, the D20 to D31 the dozers of landscaping in Japan and Europe.
On used dozers, operating hours, undercarriage (tracks, rollers, sprockets – the most expensive item), transmission and steering clutches, blade and hydraulics count, on mining trucks the maintenance history and the condition of generator and wheel motors; parts run through the Komatsu network.
Sources: Kennwerte der Modelle Komatsu Bergbau (weitere Modelle), Komatsu Ltd. (Hersteller)
Technical data
Engine
| Engine model | SAA4D102E-2correct |
|---|---|
| Power | 55.9 kWcorrect |
| Cylinders | 4correct |
| Displacement | 3,932.9 cm³correct |
| Aspiration | turbochargedcorrect |
| Coolant capacity | 26.9 lcorrect |
| Engine oil capacity | 12.5 lcorrect |
Dimensions and weights
| Ground clearance | 381correct |
|---|---|
| Unladen weight | 7,652.1 kgcorrect |
Drivetrain and chassis
| Gearbox type | dual-path hydrostatic transmission transmissioncorrect |
|---|---|
| Forward gears | 3correct |
| Reverse gears | 3correct |
Working data
| Hydraulic pressure | 206.2correct |
|---|---|
| Fuel tank capacity | 165 lcorrect |
Other data
| Cab height | 2,691.4correct |
|---|
More machines with this engine (SAA4D102E-2, 5)
Where this model stands
Power-to-weight ratio: 7.3 kW/t (56 kW / 7.7 t)
Stronger than 18% of the mining equipment in the register — out of 944 models with a stated power figure.
Calculated from the documented figures above — not a rating.
Frequently asked questions
How much power does the Komatsu D31PX-21 KOMSTAT II have?
The Komatsu D31PX-21 KOMSTAT II delivers 55.9 kW.
How much does the Komatsu D31PX-21 KOMSTAT II weigh?
The unladen weight is 7,652 kg.
What engine does the Komatsu D31PX-21 KOMSTAT II have?
4 cylinders, 3,933 cm³ displacement.
What to check before buying
- Check the hour meter against the service records — a replaced instrument is the most common gap.
- Compare the data plate and chassis number with the papers.
- Check the weights in the papers against the figures here — attachments change them.
- Load the hydraulics and watch for sag.
- Ask about parts availability for this build year — the running costs hang on it.
A general list for this type of machine — no substitute for an inspection or an appraiser.
We do not sell machines. We ask the dealers who carry this model and come back with price and lead time.
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This page carries 15 individual figures for this model. They come from 1 recorded source; every figure can be traced there. What we cannot document is not here — we leave gaps open rather than estimate them.
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Other models in this series
Sources: [1]
Dump truck in 3D section
Turn the model, look inside and click an assembly — each one is explained.