Description
The NF75B is a 75 mm bore tractor hydraulic lift cylinder with a 32 mm rod, 110 mm stroke, and 350 mm mounting distance. It shares its bore, rod, and stroke with one other cylinder in this product range — the TB600.55B.2. The only dimension that separates them is mounting distance: 350 mm on the NF75B versus 425 mm on the TB600.55B.2.
That 75 mm difference in pin-center spacing is enough to make these two cylinders non-interchangeable. A machine with 350 mm bracket pivot spacing cannot accept a 425 mm mounting distance cylinder without bracket modification, regardless of how identical the bore, rod, and stroke appear. This is the central selection issue for anyone comparing these two models.
Ever-Power supplies the NF75B as an aftermarket replacement for agricultural tractor hydraulic lift applications. Confirm the mounting distance of your existing cylinder — not just the bore and stroke — before ordering.
NF75B — Technical Specifications
| Parameter | Value | Notes |
|---|---|---|
| Bore Diameter | 75 mm | Between 63 mm and 80 mm bore groups; ~42% more piston area than 63 mm bore |
| Rod Diameter | 32 mm | Same as NF63C; same as TB600.55B.2 |
| Stroke | 110 mm | Same as NF63C and TB600.55B.2 |
| Mounting Distance | 350 mm | 75 mm shorter than TB600.55B.2 (425 mm) — the distinguishing dimension |
| Application | Agricultural tractor hydraulic lift systems | Confirm mounting distance of existing cylinder before ordering |
| Supplier | Ever-Power | OEM and aftermarket supply; custom specifications on inquiry |
Same Bore, Same Rod, Same Stroke — Still Not Interchangeable
The NF75B and TB600.55B.2 share three dimensions: 75 mm bore, 32 mm rod, 110 mm stroke. A buyer who measures only these three parameters on a failed cylinder and finds 75 mm, 32 mm, and 110 mm has not yet determined which model is required. The mounting distance measurement resolves the question completely.
| Model | Bore | Rod | Stroke | Mtg. Dist. | Extended |
|---|---|---|---|---|---|
| NF75B | 75 mm | 32 mm | 110 mm | 350 mm | 460 mm |
| TB600.55B.2 | 75 mm | 32 mm | 110 mm | 425 mm | 535 mm |
What the 75 mm mounting distance difference means in practice:
A machine designed around the NF75B has its two mounting bracket pivots 350 mm apart when the cylinder is retracted. The rod-end pin sits in its bracket with the cylinder fully compressed. If a TB600.55B.2 (425 mm retracted length) is fitted into the same machine, the rod-end pin is 75 mm short of its bracket in the retracted position — the cylinder physically cannot be mounted without pulling the bracket or cutting a longer mounting slot. In the extended position, the TB600.55B.2 would reach 535 mm where the machine expects 460 mm — 75 mm of over-travel. Neither condition is acceptable without redesigning the installation geometry.
75 mm Bore: Between 63 mm and 80 mm
The 75 mm bore places the NF75B between the 63 mm group and the 80 mm TB600 in terms of force potential. Piston area at 75 mm bore is approximately 4,418 mm² (π × 37.5²). That is about 42% more than a 63 mm bore (3,117 mm²) and about 12% less than an 80 mm bore (5,027 mm²).
| Bore | Piston Area | Force @ 160 bar (ref.) | Force @ 180 bar (ref.) |
|---|---|---|---|
| 63 mm | 3,117 mm² | ~49.9 kN | ~56.1 kN |
| 75 mm (NF75B) | 4,418 mm² | ~70.7 kN | ~79.5 kN |
| 80 mm | 5,027 mm² | ~80.4 kN | ~90.5 kN |
Engineering Reference Note: Force figures above are theoretical calculations based on bore geometry and reference pressure only — not rated product specifications. Actual force depends on the hydraulic system’s operating pressure, valve restrictions, and circuit losses. No rated pressure for the NF75B has been confirmed by Ever-Power for publication here.
The 75 mm bore is not a standard ISO metric bore size in the same way that 63 mm and 80 mm are. Its presence in this product range indicates it corresponds to a specific machine family whose hydraulic system was designed around this intermediate bore diameter. Selecting a 75 mm bore cylinder is therefore a matter of matching the original machine specification — not a choice between a smaller and a larger standard option.
32 mm Rod: Proportioning for a 75 mm Bore
At 32 mm, the rod diameter gives a rod-to-bore ratio of 32/75 = 0.43 — close to, but slightly narrower than, the 35/80 = 0.44 ratio of the TB600. For a 110 mm stroke in a well-aligned tractor lift installation, a 32 mm rod provides adequate stiffness against axial compressive loading. Buckling is not a significant concern at this stroke length.
The rod diameter determines the end-connection dimensions — pin diameter, clevis bore, and eye dimensions will all be sized for 32 mm. When ordering a replacement, confirm that the rod-end pin diameter on the machine matches what a 32 mm rod requires. This is particularly important if a previous repair substituted a cylinder with a different rod diameter, which may have been shimmed or adapted at the pin — the replacement should restore the original specification rather than perpetuate the adaptation.
There is also a functional note for double-acting configurations: the 32 mm rod occupies a cross-sectional area of approximately 804 mm² on the rod side of the piston. The effective annular area for retraction (bore area minus rod area) is approximately 4,418 − 804 = 3,614 mm². At the same pressure, retraction force is therefore about 82% of extension force — standard for a cylinder of this rod-to-bore ratio.
110 mm Stroke and 350 mm Mounting Distance as a Paired Geometry
Stroke and mounting distance together define the full operating envelope of the cylinder: 350 mm in the retracted position, 460 mm at full extension. The machine’s lift linkage is designed so that the lift arm completes its travel range within that 110 mm of cylinder movement — from the lowest implement position (cylinder retracted, 350 mm) to the highest (cylinder extended, 460 mm).
The 350 mm mounting distance on the NF75B is notably shared with the NF63C (63 mm bore, 32 mm rod, 110 mm stroke). Both cylinders have the same 350 mm mounting distance and the same 110 mm stroke — but the NF63C has a smaller bore and therefore a different force output. A machine designed for the NF75B needs the 75 mm bore’s force level at its designed operating pressure. Fitting an NF63C would reduce force output significantly at the same pressure. Fitting a TB600.55B.2 would have the wrong mounting distance entirely. Neither substitution works without system redesign.
This illustrates a recurring theme in replacement cylinder selection: similar dimensions across different models can create confusion, but the full set of specifications — bore, rod, stroke, and mounting distance — must all match the original before a cylinder can be considered a compatible replacement.
Cylinder Force and Hitch Lift Capacity Are Not the Same
At 75 mm bore and a reference pressure of 160 bar, the NF75B generates approximately 70.7 kN of theoretical extension force. That is the force along the cylinder axis at the rod tip. What the tractor actually lifts at its hitch points depends on the mechanical advantage of the lift linkage: the length of the lift arms, the distance from the cylinder attachment point to the pivot, the angle of the cylinder relative to the arm, and the position of the implement.
Rated hitch lift capacity — the figure quoted in tractor brochures and specifications — is established through whole-machine testing to standardized protocols. It accounts for all these mechanical factors. That number cannot be derived by multiplying cylinder bore area by system pressure. A machine rated to lift 1,200 kg at the hitch may use a 75 mm bore cylinder operating at 160 bar — but those numbers do not arithmetically combine to produce 1,200 kg. The linkage geometry is the conversion factor, and it is machine-specific.
How to Confirm the NF75B Is the Correct Replacement
Because the NF75B and TB600.55B.2 share bore, rod, and stroke, measuring all four primary dimensions is essential. The mounting distance measurement is the one that definitively identifies which model you need.
| Measurement | NF75B Value | Method |
|---|---|---|
| Mounting Distance ← decisive | 350 mm | Pin-center to pin-center, cylinder fully retracted; tape measure |
| Bore | 75 mm | Inside barrel diameter (bore gauge or calculated from OD) |
| Rod Diameter | 32 mm | Calipers on clean rod surface |
| Stroke | 110 mm | Extended pin-pin (460 mm) minus retracted pin-pin (350 mm) |
| Rod-end pin diameter | To be measured | Calipers on existing pin or pin bore in bracket |
| Base-end pin diameter | To be measured | Measure separately; may differ from rod end |
| End connection type | To be confirmed | Identify clevis, eye, or other at both ends |
| Port specification | To be confirmed | Thread type and size, number of ports, port location on body |
If the cylinder is seized and cannot be stroked for measurement: The mounting distance (350 mm) can still be measured from pin-center to pin-center in the retracted position. The bore can be estimated from the barrel outside diameter if the wall section is accessible. The stroke, if unavailable by direct measurement, should be confirmed from the machine’s service manual before ordering. For an inquiry based on partial measurements, include photographs of both ends and the full cylinder body — the end connection style and any body markings assist with identification.
When the Hydraulic Lift Needs Attention
The symptoms below involve the lift system as a whole. Isolating the cylinder from the circuit before condemning it avoids replacing a functioning cylinder when the actual fault lies elsewhere.
Implement slowly lowers under load
Disconnect the hydraulic lines and cap the cylinder ports. If drifting stops, the cylinder is holding — the leakage source is in the control valve, check valve, or line connections. If drift continues with ports capped, the cylinder’s internal piston seal is a more likely source. Slow, load-independent drift that persists across all load weights tends to point toward the control valve rather than the cylinder.
Insufficient lift force under load
Check system hydraulic pressure first. If the relief valve is set too low, or if the pump is worn and unable to reach working pressure, lift force will be reduced regardless of cylinder condition. A cylinder with internal bypass will typically show as slow drift rather than as an immediate inability to lift — confirmed pressure loss at the system level is a more common explanation for sudden reduction in lift force.
Rod seal weeping or dripping
Inspect the rod surface for scoring before ordering seals. A scored rod destroys new seals in short order. If the rod surface is clean and undamaged, a seal rebuild may be sufficient. If the rod has surface damage — linear scratches, pitting, or a bent section — address the rod condition as part of the repair rather than treating it as a seal replacement job.
Cylinder installed but lift travel range is wrong
If the implement cannot reach its designed maximum height, or if the cylinder reaches its internal stop before the lift arm reaches its mechanical end position, check whether the correct cylinder was fitted. A TB600.55B.2 (425 mm mounting distance) installed in a machine designed for an NF75B (350 mm) will produce exactly this symptom — the longer mounting distance shifts the entire travel range relative to the linkage geometry.
What to Include in an NF75B Quotation Request
Given that the NF75B and TB600.55B.2 share bore, rod, and stroke, confirming the mounting distance in your inquiry is essential. Without it, the correct model cannot be identified from bore and stroke alone.
- Reference number: NF75B
- Confirmed mounting distance: 350 mm (the distinguishing dimension vs TB600.55B.2)
- Confirmed bore (75 mm), rod diameter (32 mm), stroke (110 mm)
- Pin diameters at both ends
- End connection type at both ends
- Port thread type, size, and number of ports
- Single-acting or double-acting (confirm from port count)
- Order quantity
- Machine model and year, if known
- Working pressure, if known
- Photos of existing cylinder: full side view, both ends, port detail, any markings
Frequently Asked Questions — NF75B Hydraulic Lift Cylinder
Can the NF75B replace the TB600.55B.2, or vice versa?
No, not as a direct bolt-in replacement. They share the same 75 mm bore, 32 mm rod, and 110 mm stroke — but the mounting distance differs by 75 mm: 350 mm on the NF75B versus 425 mm on the TB600.55B.2. The bracket pivot spacing on a machine designed for one will not accommodate the other without repositioning the mounting brackets. Installing the wrong mounting distance cylinder also shifts the full stroke range relative to the lift arm geometry, meaning neither the retracted nor the extended position aligns correctly with the machine’s designed implement positions.
Why does mounting distance matter if bore and stroke are the same?
Mounting distance is the pin-center to pin-center distance in the retracted position. It determines where the cylinder physically sits between the two pivot points on the machine. Even with identical bore and stroke, a cylinder with the wrong mounting distance cannot be pinned into the correct brackets — the rod-end pin will miss its bracket by the amount of the mounting distance difference. In this case, that is 75 mm. Both the retracted and extended positions are shifted by that amount, which means neither the lowered nor the raised implement position is correct for the machine’s linkage geometry.
Why is 75 mm bore used instead of the more common 63 mm or 80 mm?
The 75 mm bore appears in specific tractor or machine families whose hydraulic lift system was designed around an intermediate force level — more than a 63 mm bore provides, less than an 80 mm bore requires. Machine designers select bore size based on the required force at the designed system pressure, the pump capacity, and the structural capacity of the lift linkage. The 75 mm bore is a manufacturer’s design choice for a specific application, not a catalog standard bore — which is why replacement sourcing must match the original specification exactly.
I measured bore and stroke correctly. Is that enough to order a replacement?
Not for the NF75B specifically — because the TB600.55B.2 shares the same bore and stroke. Measuring only those two dimensions leaves two possible models. The mounting distance (350 mm for NF75B, 425 mm for TB600.55B.2) is the deciding measurement. Also confirm rod diameter (32 mm) and the end connection details — pin diameters and connection type — which must match the machine’s brackets regardless of which model is correct.
My implement does not reach full height after fitting a replacement cylinder. What should I check?
First, verify that the replacement cylinder has the correct mounting distance. A cylinder with a shorter mounting distance than the original (for example, 350 mm fitted where 425 mm is needed) will have its extended position shifted back relative to the lift arm, reducing the maximum height reached. Also check that the stroke matches the original — a shorter-stroke replacement will reduce the available travel range. If both mounting distance and stroke are confirmed correct, check hydraulic system pressure: insufficient pressure will prevent the cylinder from fully extending under load.
What information is needed for a quotation?
Reference number (NF75B), confirmed mounting distance (350 mm — the key identifier), bore (75 mm), rod diameter (32 mm), stroke (110 mm), pin diameters at both ends, end connection type, port thread specification and count, quantity, and machine model and year if known. Photos of the existing cylinder — both ends, side view, port location — help confirm end connection geometry before quotation. Working pressure, if available from machine documentation, is also useful.
