Kubota B7100D vs. B7100HST:
| Feature | B7100 D (“gear-drive 4×4”) | B7100 HST (“hydrostatic 4×4”) |
|---|---|---|
| Transmission | 6-speed unsynchronised gear box; clutch pedal & gear-shift levers | Hydrostatic unit with 2- or 3-range selector; infinite speed via treadle pedal |
| PTO HP (claimed) | 13 hp (mechanical losses are low) (tractordata.com) | 13 hp (same engine, but expect ~½ hp loss under heavy load from the hydro) (tractordata.com) |
| Mid-PTO | Optional/rare on gear models | Standard on most HSTs—handy for belly mower or front snow-blower (mytractorforum.com) |
| Steering/Drive | Manual steering, selectable 4WD | Same chassis, slightly wider operator’s platform on later HSTs (orangetractortalks.com) |
| Operating weight* | ≈ 1 080 lb / 489 kg | 1 150 – 1 265 lb / 522 – 573 kg (hydro pump & oil add mass) (tractordata.com, tractordata.com) |
| Production years | 1976 – mid-1980s | 1980 – 1997 (two generations; “HST-D” older square-ROPS, “HSD” newer rounded-ROPS) (tractorbynet.com) |
| Typical used price† | US $3 000–5 500 (loader adds $1 500-2 000) | US $4 000–6 500; hydro premium + later build years (reddit.com) |
| *2 WD “E/HSTE” versions are lighter; numbers above are for common 4 WD variants. | ||
| †Spring 2025 auction averages. |
What those differences mean in real life
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Ease of operation
HST wins. With a treadle pedal you can inch forward/back to hook up implements or feather speed while mowing. Loader work is faster because you never clutch to change gears.
Gear wins for simple field jobs where you pick a gear and go (tilling, grading). -
Power delivery & efficiency
The hydro absorbs a little power and runs warmer, so fuel burn is fractionally higher under heavy loads. For PTO-driven tools you’ll seldom feel the difference, but for constant-pull items (ground‐driven tiller, plow) the gear-drive puts slightly more HP to the wheels. -
Maintenance & longevity
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Gear box: just 80-W-90 gear oil and two shift rails—cheap to rebuild.
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Hydro: very reliable if the oil & filters are changed (every 200 h in the Kubota manual), but a failed pump or swash plate is a four-figure repair.
Owners report 3 000-4 000 trouble-free hours from both versions when serviced on schedule. (mytractorforum.com)
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Mid-PTO & mower compatibility
If you plan to run a belly mower or front snow-blower, the HST is the easier path because most came with the 2 500 rpm mid PTO from the factory. On gear units it’s an add-on kit that’s now scarce. -
Resale value
The convenience of hydro plus the newer build dates keeps HST prices about 15-20 % higher for equal condition/hours. Collectors looking for pure simplicity or lighter weight sometimes prefer the D.
Which one should you hunt for?
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Mostly loader & mower work on tight properties → B7100 HST
Infinite speed control, standard mid PTO, and later-model parts interchange (6-lug front hubs, rounded ROPS). -
Budget-minded food-plotting, tilling, or snow-pushing → B7100 D
Fewer moving parts, lighter footprint for trailer transport, and it will still accept the same LA300-series front loaders.
Either way you’re getting the same bullet-proof 0.8 L three-cylinder Kubota diesel, identical hydraulics (3 gpm open-center), and a parts network that still stocks filters, clutches, steering boxes, and loader seals nearly 50 years after the first B7100 rolled off the line.
Bottom line: Choose D for maximum simplicity and a few hundred dollars saved; choose HST for clutch-free finesse and built-in mid-PTO versatility. Both remain legendary compact workhorses.