Allis ChalmersModel A
Allis Chalmers HD21
Agricultural
- power
- 225 hp
- displacement
- 844 ci
- Cylinders
- 6
- Forward gears
- 2
Head to head · Agricultural
Allis Chalmers HD21 vs Caterpillar D7G SA Special Application
Image not recorded
CaterpillarModel B
Caterpillar D7G SA Special Application
Crawler
- power
- 250 hp
- displacement
- 638 ci
- Cylinders
- 6
- Forward gears
- 6
Allis ChalmersAllis Chalmers HD21
vs
CaterpillarCaterpillar D7G SA Special Application
How they compare
Headline specs vs. the whole Agricultural
Engine Power
▲ D7G SA Special Application higher · +25 hp (+11%)HD21225 hp
D7G SA Special Application250 hp
Median Agricultural Tractor110 hp
HD21 is in the 84th percentile; D7G SA Special Application is in the 88th · 1,028 models
Engine Displacement
▲ HD21 higher · +206 ci (+32%)HD21844 ci
D7G SA Special Application638 ci
Median Agricultural Tractor336 ci
HD21 is in the 96th percentile; D7G SA Special Application is in the 94th · 1,083 models
Cylinders
= Effectively tiedHD216
D7G SA Special Application6
Median Agricultural Tractor5.5
HD21 is in the 74th percentile; D7G SA Special Application is in the 74th · 1,130 models
Forward Gears
▲ D7G SA Special Application higher · +4 (+200%)HD212
D7G SA Special Application6
Median Agricultural Tractor16
HD21 is in the 1st percentile; D7G SA Special Application is in the 11th · 972 models
HD21 (A)D7G SA Special Application (B)Median Agricultural Tractor
Full comparison
Every spec, side by side
General Information
| Spec | Allis Chalmers HD21 | Caterpillar D7G SA Special Application | Difference |
|---|---|---|---|
| Manufacturer | Allis Chalmers | Caterpillar | — |
| Model | HD21 | D7G SA Special Application | — |
| Category | Agricultural | Crawler, Agricultural | — |
Engine
| Spec | Allis Chalmers HD21 | Caterpillar D7G SA Special Application | Difference |
|---|---|---|---|
| Manufacturer | Allis-Chalmers | Caterpillar | — |
| Model | Not recorded | 3306 | — |
| Power Output | 225hp | 250hp | ▲ D7G SA Special Application+25 hp · +11% |
| Rated RPM | 1,800RPM | 2,000RPM | ▲ D7G SA Special Application+200 RPM · +11% |
| Cylinders | 6 | 6 | Same |
| Displacement | 844ci | 638ci | ▲ HD21+206 ci · +32% |
| Bore | 5.3in | 4.8in | ▲ HD21+0.5 in · +10% |
| Stroke | 6.5in | 6in | ▲ HD21+0.5 in · +8% |
Transmission
| Spec | Allis Chalmers HD21 | Caterpillar D7G SA Special Application | Difference |
|---|---|---|---|
| Type | Torque Converter | Gear | — |
Dimensions & Weight
| Spec | Allis Chalmers HD21 | Caterpillar D7G SA Special Application | Difference |
|---|---|---|---|
| Length | 198in | 179in | ▲ HD21+19 in · +11% |
| Width | Not recorded | 103in | — |
| Height | 99in | Not recorded | — |
| Operating Weight | 45,500lb | 40,700lb | ▲ HD21+4,800 lb · +12% |
Hydraulics
| Spec | Allis Chalmers HD21 | Caterpillar D7G SA Special Application | Difference |
|---|---|---|---|
| System Type | Not recorded | Open Center | — |
Chassis & Drive
| Spec | Allis Chalmers HD21 | Caterpillar D7G SA Special Application | Difference |
|---|---|---|---|
| Chassis Type | Not recorded | Crawler | — |
Electrical
| Spec | Allis Chalmers HD21 | Caterpillar D7G SA Special Application | Difference |
|---|---|---|---|
| Starter Type | Electric | Electric | Same |
Capacities
| Spec | Allis Chalmers HD21 | Caterpillar D7G SA Special Application | Difference |
|---|---|---|---|
| Coolant | 20gal | 12gal | ▲ HD21+8 gal · +67% |
Category context
Both models against the field
Engine Power
median 110 hpA · 84th percentile (225 hp)B · 88th percentile (250 hp)
Engine Displacement
median 336 ciA · 96th percentile (844 ci)B · 94th percentile (638 ci)
Cylinders
median 5.5A · 74th percentile (6)B · 74th percentile (6)
Forward Gears
median 16A · 1st percentile (2)B · 11th percentile (6)
Operating Weight
median 10,914 lbA · 99th percentile (45,500 lb)B · 97th percentile (40,700 lb)
A · HD21B · D7G SA Special ApplicationMedian Agricultural Tractor