THE ACREAGE EQUIPMENT FIELD GUIDE
HMT tractors: PTO power at zero speed vs working speed
Yanmar rates its i-HMT YT347 and YT359 twice: 39.5 and 52.0 PTO hp at working speed, 36.4 and 48.9 with the tractor stopped. A chipper runs parked and a flail mower runs moving.
By Acreage Equipment · Reviewed November 9, 2026 · Specification research, not a field test
THE DECISION IN NUMBERS
Yanmar i-HMT PTO ratings against the limits they straddle
From Yanmar’s 2023 YT3 sell sheet.
Scroll the table sideways on smaller screens.
| Tractor | Working speed | Zero speed | Limit between them |
|---|---|---|---|
| Yanmar YT347 | 39.5 PTO hp | 36.4 PTO hp | None crossed; both short of WC68’s over-40 full feed |
| Yanmar YT359 | 52.0 PTO hp | 48.9 PTO hp | TMG’s 50 cap, WC68’s 50 maximum, WoodMaxx’s 50+ full capacity |
Sources for this decision table (1)
- Yanmar 2023 YT3 sell sheet (PDF created October 3, 2023) ↗Specifications: Gross Power 46 / 58.9 HP; PTO Power at Working Speed 39.5 / 52.0 HP; PTO Power at Zero Speed 36.4 / 48.9 HP; 3-point hitch Category 1; 3-point lift capacity (std.) 3,307 lbf; at 24" (61 cm) 2,756 lbf
Why two figures
A hydro-mechanical transmission splits engine power between a mechanical path and a hydrostatic one. Yanmar publishes PTO power at working speed and at zero ground speed, and the zero-speed figure is about 3 hp lower on both tractors.
Which one to compare
A PTO chipper works with the tractor parked, so the zero-speed figure is closer to what it gets. A flail mower works on the move, so the working-speed figure applies. This site screens on the working-speed figure and shows both.
Where it changes the answer
The YT359’s 52.0 is over TMG’s 50-PTO-hp cap and Woodland Mills WC68’s 50; its 48.9 is under both. For WC68 the stationary figure is the relevant one, so ask Woodland Mills. For TMG’s mowers the working-speed figure applies and the YT359 is over.
What to ask
Ask the attachment maker which figure its horsepower range refers to, and keep Yanmar’s sell sheet with the quote.
Take these questions with you.
- Does the tractor publish PTO power at zero speed and at working speed?
- Does the attachment run parked or moving?
- Which figure does the attachment maker’s range mean?
- Is the tractor near a published minimum or maximum on either figure?
Keep these questions with your exact tractor and attachment details.
Use these questions in my seller briefFOLLOW THE NUMBERS
Sources & documentation
Research record reviewed November 9, 2026. Confirm the current manual and the exact revision supplied with your machine.
- Yanmar 2023 YT3 sell sheet (PDF created October 3, 2023)Specifications: Gross Power 46 / 58.9 HP; PTO Power at Working Speed 39.5 / 52.0 HP; PTO Power at Zero Speed 36.4 / 48.9 HP; 3-point hitch Category 1; 3-point lift capacity (std.) 3,307 lbf; at 24" (61 cm) 2,756 lbf
- Yanmar YT359 current U.S. product pageGross Power 58.9 HP; PTO Power 52.0 HP; 3-Point Hitch Category 1
- Woodland Mills WC68 official product pageCapacity, including full-diameter/full-infeed-speed condition; price
- Woodland Mills WC68 operator manual, Rev C, 28-May-2024 — Printed p9 product/shipping weights; p12 Cat 1 and PTO range; operation/setup sectionsPrinted p9: 20–50 PTO hp; 747 lb
- TMG TFMS50/60/72 manual, 2025-01-09p6: tractor power must not exceed 50 PTO hp; cutting width 1,250 mm
- WoodMaxx MX-9900 official product pageHorsepower and full-capacity statements
- TMG Industrial official U.S. TFM60 product page — Current price, operation weight, width and shipping weight
- TMG TFM60/68/72 manual — cover v.2022.11.29; filename 2025.01.09 — p6 power; p11 hitch adjustment; p12 specifications
- Official U.S. WC88 page: price, capacity and drive system
- Current linked WC88 operator manual, Rev C, 22-Aug-2022
- MX-9900 manual Rev C, September 18, 2026: specifications and setup
- WoodMaxx current manufacturer manual index
