Custom Extension & Tension Springs

IATF 16949–certified · 20+ years · wire 0.1–20 mm · fast sampling

GL Springs (Shanghai Guanglei Spring) designs and manufactures custom extension springs — also called tension springs — for OEMs worldwide. From small precision springs for electronics to large, heavy-duty extension springs for industrial equipment, we build to your load, length, and hook configuration in stainless, carbon, and alloy steel.

Send your drawing or sample — get a quote within 24 hours. → Get a Fast Quote

Core specifications

Hook and end types

The hooks are how an extension spring transmits its load — and they're the most important detail to get right, because they concentrate stress and are usually where a spring fails. We produce all common hook styles:

• Machine (German) hooks — formed from the last coil; economical and widely used.
• Cross-over center hooks — centered over the spring axis for balanced, aligned loading.
• Side hooks — offset to the side to clear surrounding components; cost-effective.
• Extended / raised hooks — longer reach for specific mounting geometry.
• Custom hooks — bent to your exact drawing.

Tell us how the spring mounts and what it pulls against, and we'll recommend the right hook style for strength and assembly.

Types of extension springs we manufacture

Straight-Hook (Drawbar) Extension Springs — straight hooks for flexible, secure connection in general assemblies.

Double-Hook Extension Springs — hooks on both ends for pulling two components together; one of the most common configurations.

Heavy-Duty & Large Extension Springs — large wire and long bodies for industrial machinery, agriculture, and equipment requiring high pulling force.

Stainless Steel Extension Springs — 304/316 for corrosion resistance in medical, marine, food, and outdoor use.

Applications

Extension springs are used wherever two parts must be pulled together or returned to position:

• Automotive — latches, levers, pedal and seat mechanisms
• Industrial machinery — return mechanisms, tensioning, counterbalances
• Consumer products — appliances, garage doors, trampolines
• Medical & electronics — precision pull and balance mechanisms

Why choose GL Springs

• IATF 16949 certified — automotive-grade quality control on every batch
• 20+ years of custom spring manufacturing in Shanghai
• Full custom capability — any wire size, material, and hook style to your drawing
• Engineering support — DFM feedback and reverse engineering from a sample
• Fast sampling — catalog samples (≤5 pcs) ship for the cost of freight; custom samples in 5–7 business days
• 100% inspection — dimensional and load testing against your spec

FAQ

Q:Can you make large or heavy-duty extension springs?
A: Yes — large extension springs are one of our strengths, with wire diameters up to 20 mm for high-load industrial applications.

Q:What's the difference between an extension and a tension spring?
A: They're the same thing — both names describe a close-wound spring that resists a pulling (axial) load.

Q: Do you offer samples before mass production?
A: Yes. Catalog items (≤5 pcs) ship for freight cost only; custom samples carry a $50 refundable fee (deducted from your order), typically in 5–7 business days.

Q: What's the minimum order quantity?
A: It varies by part; tell us your design and quantity and we'll advise.

Ready for a quote? Send us your load, length, and hook requirement — or just a drawing or sample. → Get a Fast Quote · Request a Sample · Talk to Our Engineers