Komatsu GD621R-1
Series: Komatsu Motor Grader
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Komatsu Motor Graders: Reading the GD Number and Dash Generation
On Komatsu graders like the GD555-5, GD655-5 or GD675-5, "GD" marks the grader line, the number sets the size class, and the digit after the dash marks the model generation. According to Komatsu, each new dash generation brings cost reduction along with features that have since become standard — in the -5 generation, the manufacturer states that Economy mode cuts the GD675-5's fuel consumption by up to 20 percent versus Power mode.
Read on 4 more paragraphs
Alongside the GD555/655/675 line, Komatsu also runs a separate, more compact lineup marked with an "A", such as the GD300A-1 and GD305A-3 — here too the digit after the dash marks the generation.
The manufacturer's own power figures — 146 kW for the GD555-5, 165 kW for the GD675-5 — fall within the range recorded in the SpecCodex database, where displacement runs from 3,921 to 12,175 cm³ and cylinder counts from 4 to 6, depending on the model.
When buying used, check operating hours, wear on the moldboard and cutting edges, play in the circle, and leak-free cylinders for the blade, ripper and steering. Testing the torque converter and transmission under load matters too.
In short: GD plus number narrows the size class, the digit after the dash marks the generation — power output and equipment level only show up on that specific machine's nameplate.
Sources: Kennwerte der Modelle Komatsu Motor Grader, — Constructionshows: GD555-5 & GD675-5 Komatsu graders, — Komatsu: GD655-6 Produktseite
Technical data
Engine
| Engine model | S6D105correct |
|---|---|
| Power | 157.8 hpcorrect |
| Rated speed | 2,500 rpmcorrect |
| Cylinders | 6correct |
| Displacement | 6,490.9 cm³correct |
Dimensions and weights
| Length | 8,382correct |
|---|---|
| Wheelbase | 6,001.5correct |
| Ground clearance | 365.8correct |
Drivetrain and chassis
| Tyre size | 13.00-24-10PRcorrect |
|---|---|
| Turning radius | 10,420 mmcorrect |
Working data
| Fuel tank capacity | 285 lcorrect |
|---|
More machines with this engine (S6D105, 9)
Frequently asked questions
How much power does the Komatsu GD621R-1 have?
The Komatsu GD621R-1 delivers 158 hp.
What engine does the Komatsu GD621R-1 have?
6 cylinders, 6,491 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.
- 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 11 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
GD200A-1
GD300A-1
GD305A-3
GD31RC-3A
GD405A-1
GD500R-2
GD505A-2
GD505R-2
GD510R-1
GD511A-1
GD521A-1
GD530A-2C
Sources: [1]
Grader in 3D section
Turn the model, look inside and click an assembly — each one is explained.