PTO Shaft → PTO Shaft for Discbines → G Series
G Series PTO Shaft — G2 to G50 Spline Tube
for Discbines, Rotary Cutters & Heavy Ag Equipment
10 rated series from 15 kW (G2) to 119 kW (G50) at 540 RPM. Wide-angle universal joints handle up to 80° deflection. Built-in friction clutch overload protection. CE-certified and ready to drop into your driveline today.
✔ CE Certified
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✔ 540 & 1000 RPM Rated
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✔ 80° Wide-Angle Joint
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✔ Friction Clutch Overload Protection
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✔ OEM Custom Available
What Is the HZPT G Series PTO Shaft?
The G Series PTO shaft (Power Take-Off shaft) is a telescoping driveline engineered to transfer rotational power from a tractor’s PTO output to pull-type or three-point-hitch implements — discbines, rotary cutters, hay balers, manure spreaders, crop sprayers, and more. It bridges the gap between your tractor’s gearbox and the implement’s input shaft, converting engine torque into usable field work.
HZPT manufactures 10 G Series grades — G2, G4, G5, G6, G7, G8, G38, G42, and G50 — each sized to a specific torque and power band. The G50, for instance, delivers a peak torque of 3,700 Nm and handles up to 119 kW (162 hp) at 540 RPM, making it one of the heaviest-duty agricultural PTO shafts in its class.
Each shaft features a wide-angle universal joint rated up to 80°, eliminating binding and vibration even on tractors with high ground clearance or steep drawbar angles — a common failure point on standard 35° or 45° joints.
G Series PTO Shaft — Power & Torque Specifications
All ratings are continuous-duty. Peak torque (MP) applies to short-duration shock loads only. Select your series based on your tractor’s PTO horsepower and operating speed.
| Series | @ 540 RPM | @ 1000 RPM | Peak Torque
MP (Nm) |
|---|
| kW | hp | Nm | kW | hp | Nm |
|---|
| G2 | 15 | 21 | 270 | 23 | 31 | 220 | 450 |
| G4 | 26 | 35 | 460 | 40 | 55 | 380 | 780 |
| G5 | 35 | 47 | 620 | 54 | 74 | 520 | 1,050 |
| G6 | 47 | 64 | 830 | 74 | 100 | 710 | 1,450 |
| G7 | 55 | 75 | 970 | 87 | 118 | 830 | 1,800 |
| G8 | 70 | 95 | 1,240 | 110 | 150 | 1,050 | 2,250 |
| G38 | 78 | 105 | 1,380 | 123 | 166 | 1,175 | 2,500 |
| G42 | 79 | 107 | 1,400 | 122 | 166 | 1,175 | 2,500 |
| G50 | 119 | 162 | 2,095 | 182 | 248 | 1,740 | 3,700 |
* MP = Peak torque (Nm). All kW and hp values are continuous-duty ratings. Verify your tractor’s actual PTO output before selecting a series.
Why the G Series PTO Shaft Outperforms Generic Drivelines
Here’s what actually differentiates a G Series PTO shaft from a commodity tube-and-yoke assembly — in measurable terms:
80° Wide-Angle Joint
Standard PTO universal joints bind above 35–45°. The G Series wide-angle joint handles up to 80° deflection continuously, eliminating vibration and premature bearing wear on high-clearance or steep-angle tractor hookups.
Friction Clutch Overload Protection
When an implement jams or stalls, the integrated friction clutch slips at a calibrated torque threshold — protecting both the tractor gearbox and the implement input shaft. Repair costs for a PTO gearbox can run $2,000–$6,000; a friction clutch is far cheaper insurance.
Telescoping Spline Tube Design
The inner spline tube slides freely inside the outer profile tube, accommodating changes in distance between tractor and implement during field operation — no loosening, no metal-on-metal galling. Minimum overlap is maintained at all stroke positions.
Full-Coverage Safety Shield
A rotating polypropylene shield covers the entire shaft assembly. It does not rotate with the shaft — so clothing, crop material, and bystanders are not drawn into the driveline. Meets CE Machinery Directive 2006/42/EC requirements.
Dual-Speed Compatibility
Every G Series grade is independently rated at both 540 RPM and 1000 RPM, covering all common tractor PTO configurations. No need to cross-reference separate part numbers for different speed outputs.
High-Strength Alloy Construction
Cross kits use induction-hardened bearing journals. Yokes are forged, not cast. Tubes are drawn-steel profile — not welded seam. The result: G50 handles 3,700 Nm peak torque without deformation or fatigue cracking under field shock loads.
Where HZPT G Series PTO Shafts Are Used
The G Series PTO shaft’s 10-grade torque range covers nearly every agricultural and light-industrial driveline application running off a tractor PTO:
🌾
Discbines & Mower-Conditioners
G5–G7 typical. PTO shaft for discbines must handle intermittent shock loads from rock strikes; friction clutch is essential.
🚜
Rotary Cutters & Flail Mowers
G4–G6. Constant high-speed operation demands tight spline fit and low-friction shield bearings to prevent heat buildup.
🌀
Hay Balers (Round & Square)
G6–G8. Cyclic tying loads and unpredictable slug feeding require robust cross kits and wide-angle capability.
💧
Crop Sprayers & Pumps
G2–G4. Lower torque, steady-state operation. 1000 RPM rating preferred for centrifugal pump drives.
🪵
Wood Chippers & Stump Grinders
G8–G50. Extreme shock loads from large-diameter wood require peak torque (MP) ratings above 2,250 Nm.
♻️
Manure Spreaders & Tillers
G5–G7. Continuous full-power operation in abrasive environments; grease-purge cross kits extend service intervals.
How to Measure a PTO Shaft — 5 Dimensions You Need
Ordering the wrong PTO shaft length or series is the most common and costly purchasing mistake. Take these five measurements before you configure your G Series order:
1
Overall Extended Length
With the shaft fully extended, measure tip-to-tip — coupling end to coupling end. This must exceed the distance between your tractor’s PTO stub and the implement input when the implement is at its furthest point from the tractor during operation (e.g., on a raised 3-point hitch). Standard recommendation: allow at least 50 mm overlap in the spline tubes at maximum extension.
2
Cross Kit Diameter
The cross kit (also called the spider or universal joint kit) must match the yoke bore of your tractor and implement. Measure the trunnion-to-trunnion width across the widest axis of the cross. Common sizes range from 27 mm (light duty) to 48 mm (heavy duty, G8+). Mixing cross kit sizes will cause immediate failure.
3
Inner Tube Diameter (Profile)
The inner spline tube slides inside the outer tube. Measure the outer diameter of the inner tube. This profile must match its corresponding outer tube to slide freely without excessive slop. Common G Series profiles: triangular (lemon), star (trilobal), and square cross-sections — interchangeable only within the same profile family.
4
Outer Tube Length & Diameter
Measure the outer tube from its yoke end to its open end, then measure its outside diameter. The OD must clear the tractor chassis and any implement framing at full articulation. Note: never cut the outer tube without recalculating minimum spline overlap.
5
Spline Count & Type
Count the number of spline teeth on the tractor-end stub shaft and the implement input shaft. Common counts: 6-spline (1-3/8″), 21-spline (1-3/8″), and 20-spline (1-3/4″). Verify both male and female spline profiles match. A mismatch here makes the shaft physically non-installable — no amount of force fixes it.
💡 Pro tip: Take all five measurements with the tractor and implement connected, engine off, PTO disengaged, and implement lowered to working height. Measurements taken with the implement raised or disconnected can be off by 50–150 mm — enough to order the wrong shaft.
Frequently Asked Questions — G Series PTO Shaft
What series should I choose for my discbine?
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Most pull-type discbines in the 9–15 ft cutting width range run off 35–75 hp PTO outputs. That maps to G5 (35 kW / 47 hp @ 540 RPM) for smaller units up to G7 (55 kW / 75 hp @ 540 RPM) for wider or faster-moving machines. If your discbine encounters frequent rock strikes or crop slug conditions, go one grade up — the G Series friction clutch will protect the input gearbox, but a correctly sized shaft reduces clutch slip frequency and extends clutch life.
Can I use a G Series PTO shaft at both 540 and 1000 RPM?
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Yes — every G Series grade publishes separate continuous-duty ratings for both 540 and 1000 RPM. The shaft itself doesn’t care which speed you use; the rated kW and Nm values simply differ because torque = power ÷ (RPM × 0.1047). Operating at 1000 RPM delivers higher power for the same torque, which is why G6 handles 74 kW at 1000 RPM vs. 47 kW at 540. Match the shaft to your tractor’s PTO output RPM setting and your implement’s required input speed.
How often do G Series cross kits and shields need to be replaced?
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Cross kit service life depends heavily on greasing intervals. Grease every 8 operating hours (or per your machine manufacturer’s schedule) with NLGI #2 lithium-complex grease. Inspect bearing needle rollers for pitting or play at the start of each season. Shield bearings — the plastic bearing rings that let the shield stay stationary — typically need replacement every 200–400 operating hours, sooner if the shield contacts the ground or fixed structures. HZPT supplies replacement cross kits and shield kits as separate line items.
Does HZPT offer custom G Series PTO shaft lengths?
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Yes. HZPT manufactures G Series PTO shafts to custom compressed and extended lengths, yoke types (quick-release, bolt-on, weld-on), and spline profiles. OEM quantities (typically 50+ pcs) unlock full custom configuration. Smaller quantities can often be accommodated from semi-finished tube stock — contact our technical team with your five measurements (see above) and we’ll confirm feasibility within 24 hours.
What is the difference between G38, G42, and G8 — they have similar ratings?
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The power ratings for G38 and G42 are close to G8, but they differ in cross kit size, yoke bore dimensions, and spline profile — making them non-interchangeable in the field even though the kW figures look similar. G38 and G42 are commonly specified for European equipment lines that use different yoke standards (e.g., Walterscheid/BLW profiles), while G8 matches North American profiles. Always confirm the cross kit diameter and yoke bore against your implement’s input shaft spec, not just the power rating.
What Customers Say About the G Series PTO Shaft
★★★★★
“I’ll be honest — I ordered the G7 thinking it might be overkill for my hay baler. Turns out my hay baler disagreed. Hit a slug of wet alfalfa the size of a golden retriever, and the friction clutch slipped clean without so much as a chirp from the gearbox. My old shaft would’ve sent me a $3,400 repair bill as a thank-you note. This thing paid for itself in one field day. Ordered two more G7s for my other equipment the same afternoon.”
BR
B. Reinhardt
Independent Farmer — Dodge County, Nebraska, USA
Verified Purchase · G7 × 3 units
Ready to Order?
Get the Right G Series PTO Shaft
Configured to Your Specs — Within 24 Hours
Tell us your five measurements, your tractor’s PTO hp, and your implement type. HZPT’s technical team will confirm the correct G Series grade, length, and spline configuration — no guessing, no returns.
OEM & wholesale inquiries welcome · MOQ negotiable · Ships worldwide
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