Last reviewed 1 Oct 2026 · 7 min read
Why tractors are classified
A tractor is a self-propelled power unit that supplies drawbar, PTO, belt-pulley and hydraulic power to implements. Exam questions usually ask which class of tractor suits which job, how to classify tractors, and how to size a tractor for a farm.
Classification
1. By type of chassis / running gear
| Type | Features | Typical use |
|---|---|---|
| Wheel tractor | Rubber-tyred wheels; the common farm tractor; high speed on roads | General farm work, transport |
| Crawler (track-type) tractor | Steel or rubber tracks instead of wheels; large ground contact area, low ground pressure, high traction and low slip | Heavy earthwork, marshy and soft land, land development, forestry |
| Half-track | Tracks at the rear, wheels at the front | Special |
| Walking (hand) tractor — power tiller | Two-wheeled, walking-behind; 5–15 hp | Small farms, puddling, orchards, hill farms |
2. By wheel arrangement and drive
| Type | Description |
|---|---|
| Two-wheel drive (2WD, 4×2) | Only rear wheels driven; small front steering wheels; the usual Indian tractor |
| Mechanical front-wheel assist (MFWD) | Front axle driven along with the rear; improves traction and reduces slip |
| Four-wheel drive (4WD, 4×4) | All four wheels about equal in size and driven; articulated or rigid frame |
| Tricycle | Two rear wheels and one or two close-set front wheels (row-crop; now rare) |
3. By use
| Class | Features |
|---|---|
| Utility (general-purpose) tractor | Wide stable stance, low centre of gravity; for tillage, transport and haulage |
| Row-crop tractor | High ground clearance, adjustable wheel track, for inter-cultivation of crops |
| Orchard (vineyard) tractor | Low height and narrow width with smooth fenders to avoid damaging trees |
| Industrial tractor | Heavy, with loader/backhoe attachments |
| Garden tractor | Small, for lawns and garden operations |
| Special-purpose tractors | Rice-field tractor, high-clearance (sugarcane), swamp tractors |
4. By power rating (Indian practice)
| Class | Approximate power |
|---|---|
| Mini tractor | Up to about 20 hp |
| Small | About 20–30 hp |
| Medium | About 30–50 hp |
| Large | Above about 50 hp |
Exact band limits differ between books and manufacturers; use the given range when a question states it.
5. By engine / cooling / fuel
- Diesel (compression-ignition) engines dominate; petrol/kerosene (TVO) types are obsolete.
- Water-cooled vs air-cooled engines; naturally aspirated vs turbocharged.
- Number of cylinders — 1, 2, 3 or 4 (Indian tractors are mostly 3- or 4-cylinder).
Main parts of a tractor (recap)
| System | Parts |
|---|---|
| Engine | Power source (diesel), cooling, lubrication, fuel and electrical systems |
| Clutch | Single/dual-stage dry clutch to engage/disengage power |
| Transmission | Gearbox, differential, final drive, PTO |
| Hydraulic system | Draft and position control; three-point hitch |
| Hitch | Drawbar, three-point linkage (Category I, II, III) |
| Steering and brakes | Manual or power steering; mechanical or oil-immersed brakes |
| Chassis and tyres | Frame, axles and wheels; rear tyres larger for traction |
| Operator's station | Seat, controls, ROPS (roll-over protective structure) |
Power measurement — types of tractor power
| Power | Meaning |
|---|---|
| Engine (brake) power | Power at the engine flywheel |
| PTO power | Power available at the power take-off shaft (typically 540 or 1000 rpm); about 85–90 % of engine power |
| Drawbar power | Power available to pull implements = drawbar pull × speed; typically about 50–60 % of engine power on a firm surface |
| Belt-pulley power | Power available at the belt pulley for stationary work |
| Hydraulic power | Power from the hydraulic pump |
FormulaDrawbar power
Tractor tests
- Nebraska tractor test (USA) is the international model; in India, tractors are tested at the Central Farm Machinery Training and Testing Institute (CFMTTI), Budni (M.P.) and approved regional centres, in line with BIS standards. Tests give PTO power, drawbar power, hydraulic lift capacity, fuel consumption, and noise.