Center-Hung vs Offset Pivot Floor Spring: Pivot Position, Offset Arm & Selection Guide

03 2026.09
Center-Hung vs Offset Pivot Floor Spring: Pivot Position, Offset Arm & Selection Guide

Center-Hung vs Offset Pivot Floor Spring: Pivot Position, Offset Arm & Selection Guide

When selecting a floor spring system, buyers often focus first on door weight, door width and floor spring load capacity. However, another important factor is the door pivot position. Terms such as center-hung pivot, offset pivot, center arm, offset arm and top pivot describe different door support and operating configurations.

The main difference between a center-hung and an offset pivot system is the location of the door's rotation axis and the hardware used to connect the door to the floor spring. A center-hung configuration keeps the pivot arrangement close to the door's center line, while an offset configuration moves the pivot position to suit specific door structures, swing paths, rebated doors or installation requirements.

This guide focuses specifically on pivot position, center-hung arms, offset arms and hardware selection. It is intended for door manufacturers, importers, distributors, project suppliers and architectural hardware buyers who need to confirm the correct floor spring accessories before ordering. For general floor spring selection by door weight and door type, see our Floor Spring Selection Guide.

Quick Summary for Buyers

  • Center-hung and offset pivot systems differ mainly in pivot position and the connecting hardware configuration.
  • Center-hung systems commonly use center arms and center pivot hardware to support and operate the door.
  • Offset arms are used when the door's rotation axis needs to be moved to suit door thickness, frame structure, rebated door construction or swing clearance.
  • CHIEN CHIN small offset arms can be evaluated for selected doors around 60–120 kg and approximately 40–60 mm thick, while larger offset arms are available for heavier door configurations.
  • Before ordering, confirm the floor spring model, door weight, door thickness, pivot position, existing hardware and installation dimensions.

1. What Is the Difference Between Center-Hung and Offset Pivot Floor Spring Systems?

The difference is not mainly in the hydraulic principle of the floor spring itself. The key difference is the door rotation axis and the hardware used between the door and the floor spring.

Comparison Center-Hung System Offset Pivot System
Pivot Position Pivot arrangement located around the center line of the door system Pivot point is offset to suit the required door swing and structure
Typical Hardware Center arm, center-hung bottom arm, center pivot / top pivot Small offset arm, large offset arm and related pivot hardware
Selection Factors Existing pivot position, floor spring model, mounting points and door construction Door weight, thickness, swing path, frame clearance and offset requirement
Purchasing Note Confirm compatibility with the existing center-hung hardware Do not select an offset arm only by its physical size

Key Point: A center-hung system is not automatically better than an offset system, and vice versa. The correct configuration depends on the door structure, required pivot position and installation conditions.

2. What Is a Center-Hung Floor Spring System?

In a center-hung configuration, the door is supported and operated through hardware aligned with the center pivot arrangement. Depending on the floor spring and door design, the system may use a center arm, center-hung bottom arm and center pivot / top pivot.

Center Arm 200-CA

The Center Arm 200-CA connects the door with the floor spring mechanism and transfers movement during opening and closing. Compatibility should be checked according to the floor spring model, mounting position and existing installation.

Center Pivot Hardware

Center pivot components support the door's rotation and maintain alignment between the upper and lower pivot points. CHIEN CHIN provides several center pivot configurations for different door structures and installation requirements. For replacement projects, buyers should compare the original pivot dimensions, mounting position and floor spring model before ordering replacement components.

3. What Is an Offset Pivot Floor Spring System?

An offset pivot system is used when the door's rotation axis needs to be moved away from the standard center position. This may be required because of door thickness, rebated door construction, frame clearance, existing mounting points or the required swing path.

In these cases, an offset arm helps connect the floor spring to the door while positioning the pivot axis according to the door structure. Therefore, an “offset floor spring” usually refers to the overall floor spring and offset hardware configuration rather than a completely different hydraulic floor spring mechanism.

When Is an Offset Arm Commonly Considered?

  • The door requires an offset rotation axis
  • The door is thick or has a special frame construction
  • A rebated door requires a different pivot position
  • The swing path must clear the frame or surrounding structure
  • Existing mounting points require an offset configuration
  • Heavy commercial doors require a specific pivot and arm arrangement

4. Small Offset Arm vs Large Offset Arm: How Are They Different?

Offset arms should not be selected only by their physical size. Door weight, door thickness, pivot position, floor spring model and overall door structure must be considered together.

Item Small Offset Arm Large Offset Arm
Door Weight Reference Approx. 60–120 kg Approx. 150–300 kg
Door Thickness Reference Approx. 40–60 mm For thicker door configurations; product selection should be confirmed individually
Typical Application Medium commercial doors and selected door structures Heavy doors, large commercial doors and higher-load applications
Main Function Provides offset pivot positioning and installation flexibility Provides offset pivot positioning for heavier door structures

* Door weight and thickness figures above are selection references based on current CHIEN CHIN product specifications. Final selection must consider the complete door structure, floor spring model, pivot position and installation conditions.

5. Center-Hung or Offset Pivot? Check These 4 Conditions First

Step 1 | Confirm the Pivot Position

Determine whether the existing door uses a center-hung arrangement or requires an offset pivot position. For replacement projects, retain information about the original mounting points, arm type and pivot position whenever possible.

Step 2 | Confirm Door Weight and Thickness

Door weight and thickness affect the required arm and pivot hardware. A medium-weight door may use a small offset arm, while heavier and thicker doors may require a larger offset arm or other heavy-duty pivot components.

Step 3 | Confirm Floor Spring and Accessory Compatibility

Center arms, center pivots and offset arms are not automatically interchangeable across all floor spring models. Check the existing floor spring model, spindle, pivot position, mounting dimensions and accessory configuration before ordering.

Step 4 | Check Door Swing and Clearance

If the door may interfere with the frame, wall, decorative finish or surrounding hardware while opening, pivot position becomes particularly important. The complete swing path should be checked before finalizing the floor spring and arm configuration.

6. Common Purchasing Mistakes with Offset Pivot Hardware

  • Checking only the floor spring body: A compatible floor spring does not automatically mean the existing arm and pivot hardware will fit.
  • Selecting an offset arm only by door weight: Door thickness, pivot location and frame construction must also be checked.
  • Changing pivot configuration during replacement: Existing door preparation and mounting points may not support a different pivot arrangement without modification.
  • Ignoring the swing path: Changing the pivot position also changes the geometry of the door movement and clearance.

7. What Information Should Buyers Provide Before Ordering?

For importers, distributors, door manufacturers and project suppliers, providing complete information helps avoid incorrect offset arms, missing pivot accessories or compatibility issues during bulk purchasing.

  • Existing floor spring model
  • Door material and door type
  • Door weight
  • Door thickness
  • Door width
  • Center-hung or offset pivot position
  • Photos of the existing arm, pivot and spindle
  • Mounting dimensions and site photos
  • Left / right handing if applicable
  • Required quantity
  • OEM / ODM, packaging or project supply requirements

8. Related Floor Spring Accessories

  • Center Arm 200-CA: Connecting and transmission hardware for center-hung floor spring configurations.
  • Center Pivot 200-1P: One of the center pivot options for different door and installation configurations.
  • Small Offset Arm: For selected medium-load and offset pivot door configurations.
  • Large Offset Arm: For heavier doors and higher-load offset pivot configurations.
  • Interchangeable Cam Spindle: Standard and extended spindle options for installation adjustment and replacement requirements.
  • Floor Spring Accessories: View center arms, pivots, offset arms, spindles and related floor spring hardware.

Technical Information Source | CHIEN CHIN Door Control Hardware Experience

This article is based on CHIEN CHIN floor spring accessory specifications and practical selection factors including pivot position, door weight, door thickness, mounting configuration and compatibility between floor springs, center arms, center pivots and offset arms.

Center-hung or offset pivot hardware should not be selected only by door weight or accessory dimensions. Door construction, floor spring model, pivot position, mounting points and swing clearance should be reviewed together before final selection.

Selection Note: Door weight and thickness values shown in this guide are reference values based on current CHIEN CHIN product specifications. Final compatibility should be confirmed according to the complete door and installation conditions.

Learn more about CHIEN CHIN | Floor Spring Accessories | Certifications & Test Reports

9. Frequently Asked Questions

Q1: What is the difference between a center-hung and offset pivot floor spring system?

The main difference is the door rotation axis and the hardware configuration. A center-hung system uses center-aligned pivot hardware, while an offset system moves the pivot point to suit door structure, swing clearance or installation requirements.

Q2: When is an offset arm required for a floor spring?

An offset arm may be considered when the rotation axis needs to be moved because of door thickness, rebated construction, frame clearance, mounting position or required swing path. Door specifications should be checked before selection.

Q3: How do I choose between a small and large offset arm?

CHIEN CHIN small offset arms can be evaluated for selected doors around 60–120 kg and approximately 40–60 mm thick. Large offset arms are intended for heavier and thicker door configurations. Final selection should also consider pivot position, floor spring model and door structure.

Q4: Can a center-hung arm be directly replaced with an offset arm?

Not necessarily. The pivot arrangement, mounting dimensions and door preparation may be different. The existing floor spring model, pivot position, spindle and mounting points should be checked before changing the hardware configuration.

Q5: Are offset arms suitable for rebated wooden doors?

Offset arms are commonly used when the door construction requires the pivot point to move away from the center position, including certain rebated door configurations. The exact arm should still be selected according to door weight, thickness, pivot position and installation dimensions.

Q6: What information should importers provide for bulk floor spring accessory orders?

Provide the floor spring model, door material, door weight, thickness, width, center-hung or offset configuration, existing hardware photos, mounting dimensions, quantity and any OEM / ODM or packaging requirements.

Need Help Selecting Center-Hung or Offset Pivot Hardware?

Send us your floor spring model, door weight, thickness, pivot position, existing hardware photos and purchasing quantity. CHIEN CHIN can assist importers, distributors and project suppliers with floor spring accessory selection, bulk purchasing and OEM / ODM requirements.

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