Hermann Lanz D 634
Built: 05/1974–09/1978 · Series: D-Reihe
More machines from model year 1974
Not the right version? The data comes from vehicle registers holding many near-identical versions side by side. Photograph the data plate — we read make and type from it. Open the scanner e-mail address required
Hermann Lanz Aulendorf D series – not the Bulldog: air-cooled tractors from Upper Swabia, 1949–1967
The D series from Hermann Lanz of Aulendorf is often confused with the Lanz Bulldogs from Mannheim – wrongly, because apart from the name the two companies have nothing in common. After the war the Upper Swabian firm built its own tractors with bought-in air-cooled diesel engines, mostly from MWM, and sold them mainly to small farms in southern Germany and Austria; the 'Austria-Diesel' in the register is one such export version.
Read on 3 more paragraphs
The type designation is consistent: D for diesel, the number roughly the power class – from the small D 12 and D 15 to the D 240 and D 245 of the 1960s. The suffix S marks improved versions, AE an equipment level. In the register the models run from 8.8 to 43.9 kW, from 905 to 3,400 cm³ with one to four cylinders and from 1,120 to 3,950 kg unladen; top speeds lie between 16.5 and 29.8 km/h.
The production periods of the individual models are recorded in the register to the month – a sign of the small batches and frequent model changes of a mid-sized maker that ended tractor production in 1967.
For collectors rarity counts; for condition, engine bearings, the cooling blower and the often simple gearboxes are decisive. Spare parts are available through the MWM engine connection and a small but active enthusiast scene.
Sources: SpecCodex register, model data: Hermann Lanz D-Reihe, Hermann Lanz Aulendorf (Wikipedia)
Technical data
Engine
| Fuel | dieselcorrect |
|---|---|
| Power | 34 hp (24.9 kW)correct |
| Rated speed | 2,400 rpmcorrect |
| Cylinders | 2correct |
| Displacement | 2,078 cm³correct |
| Bore | 105 mmcorrect |
| Stroke | 120 mmcorrect |
| Injection pressure | 185 barcorrect |
| Cooling | water-cooledcorrect |
Dimensions and weights
| Length | 3,300 mmcorrect |
|---|---|
| Width | 1,520 mmcorrect |
| Height | 1,300 mmcorrect |
| Wheelbase | 2,080 mmcorrect |
| Ground clearance | 330 mmcorrect |
| Unladen weight | 1,780 kgcorrect |
Drivetrain and chassis
| Drive | rear-wheel drivecorrect |
|---|---|
| Gearbox | 8V/2Rcorrect |
| Front tyres | 6.00-16 ASFcorrect |
| Rear tyres | 11-28 AScorrect |
| Top speed | 28.1 km/hcorrect |
Origin and approval
| Construction | unit construction (no separate frame)correct |
|---|---|
| Units built | 132correct |
Where this model stands
Power-to-weight ratio: 14 kW/t (25 kW / 1.8 t)
Power class: Compact (< 40 hp)
Stronger than 20% of the tractors in the register — out of 15,663 models with a stated power figure.
Calculated from the documented figures above — not a rating.
Frequently asked questions
How much power does the Hermann Lanz D 634 have?
The Hermann Lanz D 634 delivers 34 hp.
How much does the Hermann Lanz D 634 weigh?
The unladen weight is 1,780 kg.
What engine does the Hermann Lanz D 634 have?
2 cylinders, 2,078 cm³ displacement, Diesel.
How fast does the Hermann Lanz D 634 go?
Top speed is 28.1 km/h.
What are the dimensions of the Hermann Lanz D 634?
3,300 mm × 1,520 mm × 1,300 mm.
When was the Hermann Lanz D 634 built?
Production years: 05/1974–09/1978.
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.
- 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.
We do not sell machines. We ask the dealers who carry this model and come back with price and lead time.
Request a quote →
We ask the suppliers and come back with price and lead time.
Request spare parts →
This page carries 23 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.
Missing a figure you were looking for? Report it →
Know this machine better? Have a photo, a manual, or know that a figure is wrong? Add it to the register →
Other models in this series
Sources: [1]
Tractor in 3D section
Turn the model, look inside and click an assembly — each one is explained.