Heavy-Duty PTO Shaft for Krone Round Balers — Size 4 & Size 6
Our PTO Shaft for Krone Round Balers is engineered for reliable power transmission in demanding baling operations. Manufactured from high-strength alloy steel with precision machining and heat treatment, it delivers outstanding torque capacity, wear resistance, and long service life. Available in standard and CV configurations with multiple clutch options, this PTO Shaft is compatible with a wide range of Krone round baler models. OEM and ODM services, custom lengths, and bulk supply are available to meet the requirements of agricultural equipment manufacturers, distributors, and aftermarket buyers worldwide.
Heavy-Duty PTO Shaft for Krone Round Balers — CV & Standard, Size 4/6, Friction & Cutout Clutch
Product Title: PTO Shaft for Krone Round Balers | CAT3/CAT4 Constant Velocity Driveline, 1000–1800 Nm Clutch Options

Compatibility with Krone Round Baler Models
This Krone baler driveline covers eight confirmed model families — KR100, KR125, KR130, KR155, KR160, KR1250, KR1260, KR1500, and KR1550 — using Size 4 (CAT3) or Size 6 (CAT4) CV shafts with a standard 1.375‑6 spline tractor connection. Both constant velocity (CV) and standard universal-joint configurations are stocked so operators can match the Krone baler driveline spec sheet exactly without adapters or shimming.
Clutch type varies by model: KR100‑160 use FT34 friction clutch at 1,000 Nm; KR1500/1800 step up to FT32 (1,000 Nm) or FT42 (1,450 Nm); and the 1500V / 1250MC variants require a K64/2 cutout clutch rated at 1,050 or 1,500 Nm. Confirm your baler serial-number prefix before ordering to select the correct torque bracket.
| Krone Model | PTO Shaft Type & Size | Clutch / Protection |
|---|---|---|
| KR100 / 125 / 130 / 155 / 160 | Size 4 Standard or CV · 1210 · 1.375‑6 | FT34 friction clutch · 1,000 Nm · 1.375‑6 |
| KR1500 / KR1800 | Size 4 or Size 6 CV · 1.375‑6 | FT32 @ 1,000 Nm or FT42 @ 1,450 Nm |
| KR1500V / KR1250 MC | 2380 or 2480 CV · 1.375‑6 | K64/2 Cutout @ 1,050 or 1,500 Nm |
| KR1250 / KR1550 | Size 4 (CAT3) CV · 1.375‑6 | FT32 or FF1 friction clutch @ 1,000 Nm |
| KR1250 / KR1500 (high-output) | Size 6 CV (CAT4) · 1.375‑6 | FT42 friction clutch @ 1,450 Nm |
Engineering for Heavy-Duty Performance
Krone round balers are among the highest-throughput machines in the round-bale segment, with pickup widths up to 2.20 m and bale chambers generating continuous torque spikes each time a new crop slug enters the rotor. The PTO shaft must absorb and redistribute these pulses without fatigue cracking at the yoke weld zone — the most common failure point on lower-grade shafts.
▶ Cold-Drawn Seamless Tube — Tighter OD Tolerance
Drive tubes are cold-drawn to ±0.2 mm OD, producing a finer grain structure than hot-rolled alternatives. The result is measurably higher fatigue resistance at the tube-to-yoke interface — critical for the repetitive shock loading that occurs in Krone's positive-locking bale-start sequence.
▶ Heat-Treated Alloy Steel Yokes (C45 / 42CrMo)
Yokes are precision-forged from 42CrMo alloy steel and induction-hardened at the cross-bearing bore to 58–62 HRC surface hardness. This prevents bore deformation under the sustained 1,000–1,800 Nm torque range seen in heavy silage and Comprima-style variable-chamber configurations.
▶ Constant Velocity (CV) Joint — Zero Velocity Fluctuation
The CV homokinetic joint maintains uniform output speed at operating angles up to 25°. On Krone balers where the tongue pivots during headland maneuvers, a non-CV shaft introduces cyclic vibration at 2× shaft frequency — the CV design eliminates this and reduces baler gearbox bearing wear accordingly.
▶ Friction vs Cutout Clutch — Matched to Krone Input Spec
Friction (FT-type) clutches dissipate overload energy through controlled slip, suitable for occasional jam events. Cutout (K64/2) clutches disengage immediately at the set torque — Krone's preferred protection strategy on the 1500V and 1250MC models where rotor blockages occur at higher frequency in tough crop conditions.
▶ 240-Hour Salt-Spray Zinc Coating
All steel components receive yellow zinc-chromate electroplating meeting 240 h salt-spray resistance per ISO 9227. The sliding section receives a PTFE-impregnated surface treatment that maintains consistent slip force below 80 N over the rated extension cycle, reducing operator effort during length adjustment.
▶ Quick-Release Easy-Lock Guard System
The full-length co-rotating guard uses a patented easy-lock collar that detaches and reattaches without tools in under 45 seconds. CE and EN 12965 compliant, the guard stays stationary during shaft rotation via independent bearing-cup support at both ends, meeting EU machinery directive requirements for CE-marked export markets.
Technical Specifications & Key Components
Constant Velocity PTO — Base Part Numbers
| CV Type / Speed | Tractor Spline | Base Part Number |
|---|---|---|
| CAT3 / 540 rpm | 1.375‑6 | 71R4121UCW07000 |
| CAT4 / 540 rpm | 1.375‑6 | 71R6121UCW07000 |

FT Friction Clutch Options — 1.375‑6 Spline Input
| Universal Size | Torque Limit | Part Number |
|---|---|---|
| CAT3 / S4 | 1,000 Nm | 6QE344901R |
| CAT3 / S4 | 1,000 Nm | 635E41203R |
| CAT4 / S6 | 1,800 Nm | 663H53403R |
- Shaft series: Size 4 (CAT3) and Size 6 (CAT4) constant velocity
- Tube material: Cold-drawn seamless steel, normalized, wall ≥4 mm (S4) / ≥5 mm (S6)
- Yoke material: Forged 42CrMo alloy steel, induction-hardened bore
- Spline (tractor end): 1.375‑6 (6-spline) standard; 1.375‑21 available on request
- Operating speed: 540 rpm or 1,000 rpm
- Torque ratings: 1,000 Nm (S4 / FT32/FT34) · 1,450 Nm (FT42) · 1,500–1,800 Nm (S6)
- Clutch types: FT friction (FT32, FT34, FT42), FF1 friction, K64/2 cutout
- Overlap (min. working): ≥150 mm sliding engagement at compressed length
- Surface treatment: Yellow zinc-chromate, 240 h ISO 9227 salt-spray rated
- Guard: Full-length co-rotating plastic guard, CE / EN 12965 compliant
- Custom options: Telescoping, double-telescoping, high-speed variants available
Installation & Maintenance Guidelines
- Measure working length before fitment. With the baler hitched and the three-point linkage at its lowest and highest travel positions, verify that the shaft sliding section maintains a minimum 150 mm overlap at full extension and does not bottom out (compress past the minimum closed length) at any hitch angle. An incorrect length is the leading cause of yoke pull-out failures in the field.
- Grease CV joint and cross-bearing kits every 8 operating hours. Use NLGI Grade 2 EP lithium-complex grease injected through the nipples on both the CV housing and each cross-bearing cap until fresh grease appears at the lip seal. Do not substitute with general-purpose grease — the EP additive package is required at the ball-track contact stress levels of 1,000–1,800 Nm operation.
- Verify and re-calibrate clutch torque at season start and after any slip event. For FT-type friction clutches, use a static torque wrench on the adjustment ring; the target is the value stamped on the clutch housing label (e.g., 1,000 Nm for FT32/FT34, 1,450 Nm for FT42). Spring relaxation after the first 50 hours of use is normal — re-check and adjust accordingly.
- Inspect the guard before each use. A cracked funnel end or a missing bearing cup allows the guard to co-rotate with the shaft, creating an entanglement hazard. Replacement guards are stocked separately by size (S4 / S6) and can be fitted without removing the shaft from the baler.
- Lubricate the sliding (telescoping) section each season. Apply a thin coat of NLGI Grade 2 grease to the inner and outer sliding profiles before storage and again at the start of the baling season. This prevents corrosion bonding that forces operators to apply excessive axial force — a common cause of yoke cracking at the tube weld.
- Store horizontally with yoke ends supported. Vertical storage displaces grease from the lower CV ball tracks over 60–90 days, leading to dry-start wear on first seasonal use. Use the provided storage chain hook or a flat wall bracket to keep the shaft level.
Frequently Asked Questions
Frequently Ordered Together
Customers fitting a PTO shaft to Krone balers typically order these components at the same time to complete their drivetrain service:
Universal Joints & Cross Kits
S4 and S6 cross-and-bearing kits for CV and standard yokes; grease-nipple service at 1,000 h intervals.
Right-angle bevel gearboxes for Krone pickup and rotor drives; ratio options 1:1 to 1:3.5.
PTO Shaft Safety Guards
Full-length co-rotating guards for S4 and S6 shafts; CE and EN 12965 compliant, sold by shaft size.
Sprockets & Roller Chains
Agriculture sprockets and #50/#60 roller chains for Krone net-wrap and twine-box drives.
Get the Right PTO Shaft for Your Krone Baler — Fast
Send us your baler model number, tractor spline count (6 or 21 spline), and required shaft length. We will confirm the correct Size, clutch type, and torque rating within 24 hours. Custom lengths, non-standard spline combinations, and volume pricing for dealers are all available.
Also in our PTO drivetrain range:
PTO Shaft for Square Balers |
PTO Shaft for CASE IH Round Balers |
Agriculture Sprockets |
Agricultural Gearboxes |
Universal Joints
Additional information
| editor | wm |
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