9 material differences · fewer than 12
Tractor oneInternational Harvester 15661974–1976No measured PTO figureTractor twoInternational Harvester 65881978–1981No measured PTO figure
Which should you choose?
We will not advise between these two machines, because the drive differs (Two-wheel or four-wheel drive; 4WD); they were not built in overlapping years (1974–1976; 1978–1981). The figures below are side by side so you can judge them yourself; each says whether it was measured, claimed or declared by its source.
Field by field
9 material differences · 2 fields identical or within 5%, which is not counted as material
| Field | 1566 | 6588 | Gap |
|---|---|---|---|
| Engine | |||
| Engine power, claimed claimed | 161 hp | 149.9 hp | +7% 1566 |
| Engine declared | INTERNATIONAL HARVESTER DT-436 | INTERNATIONAL HARVESTER DT-466 B | differs |
| Displacement declared | 7.14 L | 7.64 L | +7% 6588 |
| Maximum torque declared | — | 450 lb·ft · 610 N·m | — |
| Transmission | |||
| Top speed declared | 18.6 mph · 30 km/h | 18.6 mph · 30 km/h | — |
| Clutch declared | Pedal-operated ceramic clutch | — | — |
| Hydraulics & hitch | |||
| Pump flow declared | 12.0 gpm · 45.5 L/min | 18.0 gpm · 68.1 L/min | +50% 6588 |
| Rear PTO speeds declared | 1000 rpm | 540/1000 rpm | differs |
| Weight & dimensions | |||
| Unladen weight declared | 15,194 lb · 6,892 kg | 17,619 lb · 7,992 kg | +16% 6588 |
| Wheelbase declared | 104.8 in · 2,662 mm | 110.0 in · 2,794 mm | — |
| Length declared | 168.0 in · 4,267 mm | 228.3 in · 5,799 mm | +36% 6588 |
| Width declared | 112.0 in · 2,845 mm | 101.6 in · 2,581 mm | +10% 1566 |
| Ground clearance declared | 17.0 in · 432 mm | 28.4 in · 721 mm | +67% 6588 |
| Turning radius, braked declared | 11.9 ft · 3.63 m | — | — |
| Fuel tank declared | 168.0 qt · 159.0 L | 360.0 qt · 340.7 L | +114% 6588 |
Height is not in this table. It is not one measurement: the sources measure it to different points — over the cab on some machines, over the steering wheel or the exhaust on others — and the same tractor measured two ways can differ by most of a metre. It appears here only when both machines' figures carry the point they were measured to and it is the same point, which is not the case for these two. Each machine's own page prints its height as its source gives it.
International Harvester 1566 sources
- Source: Traktorenlexikon, “Farmall Farmall 1566”
- Source: Traktorenlexikon, “IHC 1466”
- Source: Traktorenlexikon, “IHC 1566”
International Harvester 6588 sources
- Source: Traktorenlexikon, “IHC 6588”
- Source: Traktorenlexikon, “IHC 3588”