GR/GS Polyurethane Spider Insert | KTR ROTEX Replacement, 92/98 Shore A, -40°C to 120°C

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GR/GS Polyurethane Spider Insert – Elastomer Cushion Pad for ROTEX Jaw Couplings

Model Number
Check below, custom

GR Series coupling spider insert, rubber mat

Product Description

The Apexcoupling GR/GS series is a high-performance polyurethane spider insert (elastomer cushion pad / buffer pad) designed for ROTEX-style jaw couplings, star couplings, and curved jaw couplings. Manufactured using premium imported polyurethane and German KTR-ROTEX inspired manufacturing processes [5†L7-L8], these elastomer elements are fully interchangeable with KTR ROTEX® GR and GS series [7†L10-L11]. The spider insert is the heart of the coupling system – transmitting torque without backlash, absorbing vibration, dampening shock, and compensating for misalignment [9†L15-L17].

Available in GR series (standard star elastomer) and GS series (solid-core servo elastomer) [5†L8-L10], with multiple Shore hardness grades (92 Shore A, 98 Shore A, and 64 Shore D) [3†L7-L9] to optimize torsional stiffness and damping characteristics, the GR/GS series is the ideal replacement element for air compressors, pumps, servo drives, machine tools, and general industrial machinery. Not an ordinary product – a premium replacement that matches or exceeds original KTR ROTEX quality [4†L6].

✅ Direct KTR ROTEX® replacement – same dimensions, superior value [7†L10-L11]. Premium imported polyurethane – high strength, wear resistance, and long service life [11†L5-L6]. -40°C to +120°C operating range – extreme temperature performance [4†L5][11†L6-L7]. Oil, ozone & UV resistant – ideal for harsh environments [4†L15]. Zero backlash – press-fit eliminates clearance [9†L17-L18]. Maintenance-free – no lubrication required.

GR vs GS – Which Series Do You Need?

Feature	GR Series (Standard Star)	GS Series (Solid-Core Servo)
Design	Standard star-shaped elastomer	Solid-core geometry for high reversing torque [5†L9-L10]
Backlash	Zero (press-fit)	Zero (pre-stressed) [12†L3]
Primary Application	General industrial, pumps, compressors	Servo drives, precision positioning, high reversing torque [12†L6-L9]
Torsional Stiffness	Good	Higher – optimized for dynamic drives [2†L18-L19]
Hardness Options	92 ShA, 98 ShA, 64 ShD [3†L7-L9]	92 ShA, 98 ShA, 64 ShD, 52 ShD [2†L8]
Temperature Range	-40°C to +100°C (up to 120°C transient) [4†L5][11†L6-L7]	-50°C to +120°C [2†L8-L9]
Best for	Pumps, compressors, conveyors, general machinery [8†L12-L13]	Servo hydraulics, test benches, CNC machines, automation [12†L21-L23]

💡 Choose GR series for standard industrial applications like air compressors, pumps, and conveyors. Choose GS series for servo drives, precision positioning, and applications requiring enhanced temperature resistance and torsional stiffness [2†L16-L19].

Key Technical Specifications

Parameter	GR Series	GS Series
Brand	Apexcoupling	Apexcoupling
Material	Premium imported polyurethane (TPU) [11†L5]	Premium imported polyurethane (TPU) [2†L7-L8]
Manufacturing Standard	German KTR-ROTEX technology [5†L7-L8]	German KTR-ROTEX technology
Hardness Options	92 Shore A, 98 Shore A, 64 Shore D [3†L7-L9]	92 Shore A, 98 Shore A, 64 Shore D, 52 Shore D [2†L8]
Color Coding	92 ShA – Yellow/Orange; 98 ShA – Red/Purple; 64 ShD – Green [3†L7-L8]	92 ShA – Yellow/Orange; 98 ShA – Red/Purple; 64 ShD – Green
Operating Temperature	-40°C to +100°C (120°C transient) [4†L5][11†L6-L7]	-50°C to +120°C [2†L8-L9]
Wear Resistance	<0.05 cm³ / 1.61 km [9†L24]	<0.05 cm³ / 1.61 km [9†L24]
Backlash	Zero – press-fit [9†L17-L18]	Zero – pre-stressed [12†L3]
Chemical Resistance	Oil, ozone, UV, and chemical resistant [4†L15]	Oil, ozone, UV, and chemical resistant
Interchangeability	Direct KTR ROTEX GR replacement [7†L10-L11]	Direct KTR ROTEX GS replacement [7†L10-L11]
Customization	OEM – custom sizes and hardness available	OEM – custom sizes and hardness available
Place of Origin	Guangdong, China	Guangdong, China

🔧 Custom sizes and Shore hardness available. Contact us with your specifications.

GR Series – Model Range & Specifications

Model	Equivalent	Outer Diameter (mm)	Inner Diameter (mm)	Height (mm)	Teeth / Flaps	Max Torque (N·m)	Max RPM
GR14	ROTEX 14	30	10	12	4	10	12000 [7†L18-L19]
GR19	ROTEX 19	40	18	14.5	6	25	10000 [7†L19]
GR24	ROTEX 24	54	26	15.2	8	45	8500 [7†L19]
GR28	ROTEX 28	65	30	19	8	80	7500 [7†L20]
GR38	ROTEX 38	80	38	22	8	150	6000 [7†L20]
GR42	ROTEX 42	95	46	24	8	220	5000 [7†L21]
GR48	ROTEX 48	104	51	25.5	8	300	4500 [7†L21]
GR55	ROTEX 55	120	60	27	8	450	4000 [7†L21]
GR65	ROTEX 65	135	68	32	8	650	3600 [7†L22]
GR75	ROTEX 75	160	80	37	10	1000	3000 [7†L22-L23]
GR90	ROTEX 90	199	100	42	10	1600	2500 [7†L23]
GR100	ROTEX 100	225	113	38	10	2200	2200 [7†L23]
GR110	ROTEX 110	255	127	42	10	3000	2000 [7†L24]
GR125	ROTEX 125	290	145	48	10	4500	1800 [7†L24]
GR140	ROTEX 140	320	165	50	10	–	– [10†L17-L18]
GR160	ROTEX 160	370	190	57	12	–	– [10†L18-L19]
GR180	ROTEX 180	420	220	64	12	–	– [10†L19]

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

GS Series – Model Range & Specifications (Solid-Core Servo Elastomer)

Model	Equivalent	Outer Diameter (mm)	Inner Diameter (mm)	Height (mm)	Teeth / Flaps
GS14	ROTEX 14 GS	30	10	12	4 [9†L28-L29]
GS19	ROTEX 19 GS	40	18	14.5	6 [9†L29]
GS24	ROTEX 24 GS	54	26	15.2	8 [9†L30]
GS28	ROTEX 28 GS	65	30	19	8 [9†L30]
GS38	ROTEX 38 GS	80	38	22	8 [9†L30]
GS42	ROTEX 42 GS	95	46	24	8 [9†L31]
GS48	ROTEX 48 GS	104	51	25.5	8 [9†L31]
GS55	ROTEX 55 GS	120	60	27	8 [9†L31]
GS65	ROTEX 65 GS	135	68	32	8 [9†L31]
GS75	ROTEX 75 GS	160	80	37	10 [9†L32]
GS90	ROTEX 90 GS	199	100	42	10

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

Spider Hardness Selection – Choose the Right Grade

The elastomer spider defines the characteristics of the entire drive system [9†L16-L17]. By varying the Shore hardness, the coupling system can be optimized for the ideal torsional characteristics [9†L18-L20].

Hardness	Color	Torsional Stiffness	Damping	Best For
92 Shore A	Yellow / Orange [3†L7]	Moderate	High	Standard general-purpose applications, good vibration damping [7†L25]
95 Shore A	Blue [9†L25]	High	Moderate	High torque, higher stiffness
98 Shore A	Red / Purple [3†L7-L8]	Very High	Moderate	Maximum torque, demanding drives, air compressors [7†L26]
64 Shore D	Green [3†L8]	Highest	Low	Precision applications, maximum torque, servo drives [7†L26-L27]
52 Shore D	–	Extreme	Lowest	ROTEX-GS only – extreme torsional stiffness for servo applications [2†L8]

💡 Selection tip: For most air compressor and pump applications, 98 Shore A offers the best combination of high torque capacity and durability [4†L13-L15]. For general-purpose applications, 92 Shore A provides excellent vibration damping. For precision servo applications, choose 64 Shore D or 52 Shore D [2†L8-L9].

Product Structure

Star-Shaped Elastomer Body – Premium TPU polyurethane with precise tooth geometry.
Multiple Teeth / Flaps – 4 to 12 teeth depending on model, engaging with coupling hubs.
Center Hole – Accommodates the coupling hub connection.
GR vs GS Design – GR features standard star geometry; GS features solid-core geometry for high reversing torque applications [5†L9-L10].

💡 How it works: The spider insert is installed between the two hubs of a jaw coupling. The spider’s teeth engage with the jaws of the hubs, transmitting torque through radial compression. The press-fit design eliminates backlash [9†L17-L18]. The elastomer flexes to absorb shock, dampen vibration, and compensate for angular, radial, and axial misalignment. By varying the Shore hardness, the coupling system can be optimized for the ideal torsional characteristics [9†L18-L20].

Product Features & Advantages

Advantage	Benefit
Premium Imported Polyurethane	High strength, wear resistance, and long service life – 3-5x longer than rubber [11†L5-L6]
German KTR-ROTEX Manufacturing	Precision engineering – fully interchangeable with KTR ROTEX® series [5†L7-L8][7†L10-L11]
Wide Temperature Range	-40°C to +120°C – suitable for extreme operating conditions [4†L5][11†L6-L7]
Zero Backlash	Press-fit design eliminates clearance – precise torque transmission [9†L17-L18]
Multiple Hardness Grades	92 ShA, 95 ShA, 98 ShA, 64 ShD, 52 ShD – tune stiffness and damping for your application [3†L7-L9][2†L8]
Oil & Ozone Resistant	Resistant to oils, greases, ozone, and UV – ideal for harsh environments [4†L15]
High Wear Resistance	<0.05 cm³ / 1.61 km – long service life [9†L24]
Maintenance-Free	No lubrication required – reduces operating costs
KTR ROTEX® Interchangeable	Direct replacement – same dimensions, no design changes required [7†L10-L11]
Vibration Damping	Excellent shock absorption – protects connected equipment
Misalignment Compensation	Compensates angular, radial, and axial displacements – reduces stress on bearings
High Temperature Resistance	Up to 120°C continuous (150°C transient) – suitable for demanding applications [4†L5][11†L6-L7]

Applications

Air Compressors – Vibration damping, oil resistance, high temperature tolerance [8†L12-L13]
Pumps – Centrifugal, gear, and diaphragm pumps [8†L12-L13]
Servo Motors – Precision positioning, zero-backlash requirements [12†L6-L9]
Machine Tools – CNC machines, milling machines [12†L22]
Packaging Machinery – Wrapping and sealing machines
Automation Technology – Pick-and-place systems, robotics [12†L22]
Printing Equipment – Register control, high-speed operation
Test Benches – Precision testing and measurement [12†L21]
Textile Machinery – Spinning and weaving equipment
Steel Mills – Rolling mills, heavy equipment

Why Choose Apex Coupling for GR/GS Spider Inserts?

Advantage	Description
Factory Direct	Competitive B2B pricing – no middlemen
Premium Imported Polyurethane	High-strength material – excellent wear, oil, and ozone resistance [11†L5]
KTR ROTEX® Interchangeable	Direct replacement – no design changes required [7†L10-L11]
German Manufacturing Technology	Precision-engineered to KTR-ROTEX standards [5†L7-L8]
Wide Temperature Range	-40°C to +120°C – suitable for extreme conditions [4†L5][11†L6-L7]
Multiple Hardness Grades	92 ShA, 95 ShA, 98 ShA, 64 ShD, 52 ShD – match your torque and damping needs [3†L7-L9][2†L8]
Wide Model Range	GR14 to GR180, GS7 to GS90 – covers most industrial applications
Zero Backlash	Press-fit design – precise torque transmission [9†L17-L18]
Not an Ordinary Product	Premium quality replacement – matches or exceeds original KTR ROTEX [4†L6][11†L7]
OEM Customization	Custom sizes and hardness available

FAQ

Q: What is a GR/GS spider insert?
A: A GR/GS spider insert (also called an elastomer cushion pad or buffer pad) is a polyurethane element that fits between the two hubs of a jaw coupling. It transmits torque, absorbs shock, dampens vibration, and compensates for misalignment. It is fully interchangeable with KTR ROTEX® GR and GS series [7†L10-L11].

Q: What is the difference between GR and GS series?
A: GR series is the standard star-shaped elastomer for general industrial applications. GS series features a solid-core geometry engineered to survive intense reversing torque impacts and is designed for servo drives and precision positioning applications [5†L9-L10][12†L3-L9].

Q: What materials are used?
A: The spider inserts are manufactured from premium imported polyurethane (TPU) using German KTR-ROTEX inspired manufacturing processes [5†L7-L8][11†L5].

Q: What is the temperature range?
A: Standard TPU operates from -40°C to +100°C with transient temperatures up to +120°C [4†L5][11†L6-L7]. High-performance TPU (GS series) operates from -50°C to +120°C [2†L8-L9].

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/Purple), 64 Shore D (Green), and 52 Shore D (GS series only) [3†L7-L9][2†L8][9†L25].

Q: Does the spider have backlash?
A: No. The press-fit design of the spider into the hubs eliminates backlash [9†L17-L18]. GS series is also backlash-free under pre-stress [12†L3].

Q: Is the spider oil and ozone resistant?
A: Yes. The polyurethane material is highly resistant to oils, greases, ozone, and UV [4†L15].

Q: Is this a replacement for KTR ROTEX®?
A: Yes. The GR/GS series is fully interchangeable with KTR ROTEX® GR and GS series – same dimensions, same performance [7†L10-L11][11†L5-L6].

Q: What are the common applications?
A: Air compressors, pumps, servo motors, machine tools, packaging machinery, automation technology, printing equipment, and general industrial machinery [8†L12-L13][12†L21-L23].

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 series (GR or GS), model (e.g., GR28, GS38), Shore hardness preference, and application details. Our engineers will recommend the optimal spider and provide a quotation within 24 hours.