GR Series Polyurethane Spider Insert – KTR ROTEX GR Replacement, Star-Shaped Elastomer

Factory Direct | Premium Polyurethane (TPU) | Star-Shaped (Quincunx) Design | Direct KTR ROTEX® GR Replacement | GR14 to GR180 | -40°C to +100°C | 92-98 Shore A | Oil, Ozone & Wear Resistant | Maintenance-Free | OEM Customizable

The Apexcoupling GR Series Polyurethane Spider Insert is a high-performance star-shaped elastomer (also known as a coupling cushion, buffer pad, or star elastic body) designed for GR-type jaw couplings and XL-type star couplings. Fully interchangeable with KTR ROTEX® GR series, this spider insert is the heart of the coupling system – transmitting torque, absorbing shock, dampening vibration, and compensating for misalignment . Manufactured from premium thermoplastic polyurethane (TPU) with multiple Shore hardness grades, these spiders deliver exceptional wear resistance, oil resistance, ozone resistance, and thermal stability for demanding industrial applications .

Available in GR14 through GR180 sizes with hardness options including 92 Shore A (standard) and 98 Shore A (high torque), the GR Series spider insert is the ideal replacement element for pumps, compressors, conveyors, rolling mills, cranes, forging presses, petroleum equipment, and general industrial machinery .

✅ Direct KTR ROTEX® GR replacement – no design changes required . Premium thermoplastic polyurethane (TPU) – high strength, wear resistance, and oil resistance . 92 Shore A standard – balanced torque and damping . -40°C to +100°C operating range – extreme temperature performance . Star-shaped (quincunx) design – absorbs shock and compensates misalignment . Maintenance-free – no lubrication required. GR14 to GR180 – comprehensive size coverage .

Key Technical Specifications

GR Series – Model & Dimensions

📐 Additional sizes and custom dimensions available upon request. Contact our engineering team for custom sizing.

Spider Hardness Selection – Choose the Right Grade

The GR Series elastomer defines the characteristics of the entire drive system. By varying the Shore hardness, the coupling system can be optimized for the ideal torsional characteristics .

💡 Selection tip: For most general industrial applications, 92 Shore A (Yellow) offers the best balance of torque capacity and vibration damping . For high-torque applications requiring greater stiffness, choose 98 Shore A (Red) . For precision applications requiring maximum torsional stiffness, choose 64 Shore D .

GR vs GS – Which Series Do You Need?

💡 Choose GR series for standard industrial applications like pumps, compressors, conveyors, rolling mills, cranes, and petroleum equipment . Choose GS series for servo drives, precision positioning, and applications requiring enhanced temperature resistance and torsional stiffness .

Product Structure

1. Star-Shaped Elastomer Body – Premium TPU polyurethane with precise star-shaped (quincunx) geometry .

2. Multiple Teeth / Flaps – 4 to 12 teeth depending on model, engaging with coupling hubs .

3. Center Hole – Accommodates the coupling hub connection.

4. Hollow Core Design (GR) – Standard star-shaped hollow design for flexibility and damping .

💡 How it works: The GR Series spider insert is installed between the two hubs of a star-type or jaw coupling. The spider’s star-shaped teeth engage with the jaws of the hubs, transmitting torque through radial compression. The polyurethane elastomer flexes to absorb shock, dampen vibration, and compensate for angular, radial, and axial misalignment . The star-shaped (quincunx) design provides excellent elastic properties, cushioning, and vibration reduction .

Product Features & Advantages

Applications

• Pumps – Centrifugal, gear, and diaphragm pumps 

• Compressors – Air and gas compressors 

• Conveyors – Material handling systems 

• Rolling Mills – Steel and metal processing 

• Cranes & Hoists – Lifting and material handling 

• Forging Presses – Heavy industrial presses 

• Petroleum Equipment – Oil and gas machinery 

• Packaging Machinery – Wrapping and sealing machines

• Printing Equipment – Register control, high-speed operation

• Textile Machinery – Spinning and weaving equipment

• Woodworking Machinery – Saws, routers, planers

• General Industrial Machinery – Light to medium-duty power transmission

Why Choose Apex Coupling for GR Series Spider Inserts?

FAQ

Q: What is a GR Series spider insert?
A: A GR Series spider insert (also called a star-shaped elastomer, coupling cushion, or buffer pad) is a polyurethane element that fits between the two hubs of a star-type or jaw coupling. It transmits torque, absorbs shock, dampens vibration, and compensates for misalignment . It is fully interchangeable with KTR ROTEX® GR series .

Q: What is the difference between GR and GS series?
A: GR series is the standard star-shaped (hollow) elastomer for general industrial applications . GS series is the solid-core servo series designed for zero-backlash, high-precision applications .

Q: What materials are used?
A: The spider inserts are manufactured from premium thermoplastic polyurethane (TPU) – offering excellent wear resistance, oil resistance, ozone resistance, and thermal stability .

Q: What is the temperature range?
A: The operating temperature range is -40°C to +100°C (continuous) with instantaneous temperatures up to +120°C .

Q: What Shore hardness options are available?
A: Available hardness grades include 92 Shore A (Yellow/Orange), 95 Shore A (Blue), 98 Shore A (Red), and 64 Shore D (Green/Purple) .

Q: What is the torque range?
A: The GR Series covers 22.4 – 2500 N·m torque capacity .

Q: Does the spider require lubrication?
A: No. The GR Series is maintenance-free – no lubrication required .

Q: Is the spider oil and ozone resistant?
A: Yes. The polyurethane material is resistant to oils, ozone, UV, and aging .

Q: Is this a replacement for KTR ROTEX® GR?
A: Yes. The GR Series spider insert is fully interchangeable with KTR ROTEX® GR series – same dimensions, same performance .

Q: What sizes are available?
A: Standard sizes include GR14, GR19, GR24, GR28, GR38, GR42, GR48, GR55, GR65, GR75, GR90, GR100, GR110, GR125, GR140, GR160, and GR180 .

Q: What are the common applications?
A: Pumps, compressors, conveyors, rolling mills, cranes, forging presses, petroleum equipment, packaging machinery, printing equipment, and general industrial machinery .

Q: Can I get a custom spider?
A: Yes. We offer OEM customization – custom sizes and Shore hardness available.

Request a Quote

Send us your model (GR19, GR28, GR38, GR48, etc.), Shore hardness preference, and application details. Our engineers will recommend the optimal spider and provide a quotation within 24 hours.