Hermann Lanz HG 25
Built: 1944–1946 · Series: Holzgas-Schlepper
More machines from model year 1944
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Hermann Lanz wood-gas tractors: gas-generator tractors from Aulendorf running on wood, peat and lignite, HG 25 and L 25 a, around 18 kW, wartime and post-war era
The wood-gas tractors from Hermann Lanz of Aulendorf arose from the fuel shortages of the wartime and post-war years, when diesel fuel was scarcely available for agriculture. Instead of liquid fuel, the HG 25 and L 25 a ran on a wood-gas generator that produced combustible gas from wood, peat or lignite to power the engine. The conversion usually involved existing diesel-tractor chassis, onto which the bulky wood-gas generator was additionally mounted.
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The register lists 2 versions here with 18.2 kW from two-cylinder engines of 3,981 cm³, an unladen weight of 2,200 kg, lengths of 2,860 to 3,400 mm, widths of 1,500 to 1,520 mm and heights of 1,640 to 1,900 mm at a rated speed of 1,550 rpm.
As testimony to the fuel shortages of their time, these wood-gas tractors reflect the improvisation of German farm machinery in the 1940s, when makers converted their tractors to gas-generator drives en masse to keep field work going despite the lack of diesel. With the end of the fuel shortage in the 1950s, wood-gas drives quickly disappeared from the fields again, giving way to a return to the diesel engine.
When buying one of these rare historic tractors, attention should go above all to the preservation of the wood-gas generator and its gas lines, the condition of the two-cylinder engine, and rust on the frame and sheet-metal parts, as well as the functioning of the gas cleaner and ignition system, which are critical for the unusual operation on generator gas; spare parts today are practically only found through vintage-vehicle collectors and museum stocks.
Sources: SpecCodex register, model data: Hermann Lanz Holzgas-Schlepper
Technical data
Engine
| Fuel | Holz/Torf/Braunkohlecorrect |
|---|---|
| Power | 25 hp (18.2 kW)correct |
| Rated speed | 1,550 rpmcorrect |
| Cylinders | 2correct |
| Displacement | 3,981 cm³correct |
| Bore | 130 mmcorrect |
| Stroke | 150 mmcorrect |
| Cooling | water-cooledcorrect |
Dimensions and weights
| Length | 3,400 mmcorrect |
|---|---|
| Width | 1,520 mmcorrect |
| Height | 1,900 mmcorrect |
| Wheelbase | 2,190 mmcorrect |
| Ground clearance | 300 mmcorrect |
Drivetrain and chassis
| Drive | rear-wheel drivecorrect |
|---|---|
| Gearbox | 5V/1Rcorrect |
| Front tyres | 6.00 x 16correct |
| Rear tyres | 9.00 x 24correct |
| Top speed | 20 km/hcorrect |
Origin and approval
| Construction | unit construction (no separate frame)correct |
|---|---|
| Units built | 235correct |
Frequently asked questions
How much power does the Hermann Lanz HG 25 have?
The Hermann Lanz HG 25 delivers 25 hp.
What engine does the Hermann Lanz HG 25 have?
2 cylinders, 3,981 cm³ displacement, Holz/Torf/Braunkohle.
How fast does the Hermann Lanz HG 25 go?
Top speed is 20 km/h.
What are the dimensions of the Hermann Lanz HG 25?
3,400 mm × 1,520 mm × 1,900 mm.
When was the Hermann Lanz HG 25 built?
Production years: 1944–1946.
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 front and rear tyre sizes: mismatched pairs strain the drivetrain.
- Shift the gearbox cold and warm — jumps only show up at temperature.
- 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.
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This page carries 21 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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Sources: Wikibooks Traktorenlexikon (CC BY-SA 4.0) (retrieved August 2026) · How we check the data
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