What is the difference between the Kubota B7100D and the B7100HST?
The Kubota B7100D and the B7100HST share the same 16 horsepower three-cylinder diesel. The difference is everything behind it: the B7100D has a six-speed gearbox and a three-speed rear PTO, while the B7100HST has a hydrostatic drive, a two-speed rear PTO and a mid PTO for a belly mower. Everything below comes from the two factory operator's manuals originally published by Kubota, which we sell as digital downloads: the B5100D/E, B6100D/E and B7100D operator's manual (code 66704-6291-5) and the B6100HST and B7100HST operator's manual (code 66204-6291-9). For the full figures, see our Kubota B7100 specifications page.
At a glance
| B7100D | B7100HST | |
|---|---|---|
| Engine | Kubota D750-A | Kubota D750-AH |
| Cylinders and displacement | 3, 46.5 cu. in. (762 cc) | 3, 46.5 cu. in. (762 cc) |
| Rated power | 16 HP at 2800 rpm | 16 HP at 2800 rpm |
| Transmission | Gear shift, 6 forward and 2 reverse | Hydrostatic, high and low range |
| Drive | Four-wheel drive | HST-D four-wheel drive, HST-E two-wheel drive |
| Rear PTO | 3 speeds: 514, 876 and 1498 rpm | 2 speeds: 540 and 850 rpm |
| Mid PTO | None listed | 2450 rpm |
| Top forward speed | 8.32 mph (6th gear) | 9.0 mph (high range) |
| Engine oil | 4.1 qts (3.9 L) | 3.6 qts (3.4 L) |
| Transmission oil | 12.2 qts (11.5 L) | 3.6 gals (13.5 L) |
| Wheelbase | 49 1/8 in. (1250 mm) | 1400 mm (HST-D), 1390 mm (HST-E) |
| Minimum turning radius | 75 in. (1.9 m) | 82 2/3 in. (2.1 m) |
| Weight | 1080 lbs (490 kg) | 1260 lbs (HST-D), 1120 lbs (HST-E) |
HST dimensions and weights are for the first tire option printed in the manual. Engine power is the rated engine figure the manuals give, not PTO horsepower.
Transmission
The B7100D has a dry single-plate clutch and a gear-shift transmission with six forward and two reverse speeds. Its manual lists each gear at 2800 engine rpm alongside the work Kubota intended it for:
| Gear | Speed | Use listed in the manual |
|---|---|---|
| 1st | 0.62 mph (1.00 km/h) | Rotary tilling, levelling, ridging |
| 2nd | 1.06 mph (1.71 km/h) | Rotary tilling, levelling |
| 3rd | 1.82 mph (2.93 km/h) | Rotary furrowing, puddling |
| 4th | 2.85 mph (4.59 km/h) | Puddling, plowing |
| 5th | 4.86 mph (7.83 km/h) | Plowing |
| 6th | 8.32 mph (13.39 km/h) | Trailing work, road travelling |
| Reverse 1 | 0.91 mph (1.47 km/h) | |
| Reverse 2 | 4.18 mph (6.73 km/h) |
The B7100HST replaces the gearbox with a hydrostatic transmission and a high-low gear shift, so speed is set by the HST rather than by a choice of gears. With 8-16 rear tires its manual gives forward speeds of 0 to 3.5 mph in low and 0 to 9.0 mph in high, and reverse speeds of 0 to 2.4 mph in low and 0 to 6.2 mph in high.
PTO
This is the difference most likely to decide which tractor suits an implement. The B7100D has a rear PTO with three speeds, 514, 876 and 1498 rpm at 2800 engine rpm, and no mid PTO is listed in its manual. The B7100HST has a two-speed rear PTO, 540 and 850 rpm, plus a mid PTO under the transmission case turning at 2450 rpm, which is what a belly mower runs from. Both manuals also list a PTO at the engine front.
Engine
The engines carry different model codes, D750-A in the gear tractor and D750-AH in the HST, but every published figure matches: three cylinders, a 2 5/8 in. bore and 2 3/4 in. stroke (68 x 70 mm), 46.5 cu. in., and 16 HP at 2800 rpm. Both use a 12V electric starter with glow plugs and a 12V 45Ah battery. The HST manual adds a fuel recommendation the gear manual does not: No. 1 diesel below -10°C (15°F) and No. 2 above.
The fluids are not interchangeable in quantity. The gear tractor holds 3.9 L of engine oil and 11.5 L of transmission oil, while the HST holds 3.4 L and 13.5 L. Fuel tank (3.4 gals) and coolant (4.9 qts) are the same on both.
Two-wheel and four-wheel drive
The gear manual covers the B7100D only, and lists its differential as driving both the front and rear wheels. It does not cover a B7100E. The HST manual covers two versions: the B7100HST-D, with four-wheel drive, and the B7100HST-E, with rear-wheel drive only. The HST-E is the lighter of the two at 1120 lbs against 1260 lbs for the HST-D.
Size
The B7100HST is the longer tractor. Its wheelbase is 1400 mm (HST-D) or 1390 mm (HST-E) against 1250 mm on the B7100D, and its minimum turning radius is 2.1 m against 1.9 m. Overall length is 2000 mm for the B7100D and 2100 to 2135 mm for the HST, depending on tires. The gear tractor is also the lightest of the three at 1080 lbs.
Production years
Neither manual gives production dates. According to TractorData, the B7100 was built from 1976 to 1985 and the B7100HST from 1977 to 1984.
Which manual do you need?
Because the PTO speeds, fluid capacities and transmission controls differ, the operator's manual for one version will mislead you on the other. If the tractor has a clutch pedal and a gear lever, you need the B7100D operator's manual. If it has the hydrostatic drive, you need the B7100HST operator's manual. Both are 48 pages. For repair work we also stock the B5100, B6100 and B7100 workshop service manual.