Not sure where to start? Let’s talk about your sourcing needs — no pressure, just honest advice from China-based experts.
An extension spring resists a pull with a closed-coil body and end hooks; stock starts at ¥1.08/pc and custom MOQs go as low as 10 pieces (2026 market data).
Open a catalog page and two extension springs can look identical while sitting twenty dollars apart in price. I trained as a mechanical engineer, so I read a part before I look at it, and that habit matters most with springs. They live hidden inside machines where nobody sees them — buried in a trampoline frame, tucked behind a garage-door pulley, soldered into a carburettor. A buyer holds the finished product, never the spring. Every decision has to be justified by numbers on paper, not by how the part photographs.
An extension spring is designed to resist a pulling force. The coils are wound tight against each other when unloaded, and each end carries a hook or a loop that connects to the load. Stretch it and it extends; let go and it pulls back. That is the opposite of a compression spring, which resists being pushed together and pushes back when compressed. One directional difference, and yet it changes the whole selection logic — material, wire diameter, cost, inspection, every decision downstream of the order. If you pick the wrong type, the part cannot be swapped late; you throw the batch away and start over.
China is the center of the global spring industry. According to the China Iron & Steel Association (2023), more than 78% of industrial spring capacity sits in southern China, and Guangdong alone hosts about 42% of the country’s metal-spring makers. Drill down on extension springs and the clusters become concrete: Jiangmen, Nanhai in Foshan, Dongguan and Shenzhen in the Pearl River Delta, then Xiamen in Fujian, Hangzhou in Zhejiang, and Ganzhou in Jiangxi — each with its own precision-spring shops, its own mix of wire suppliers and coiling machines.
The good news is that one country covers your whole price ladder, from a few-cent stock standard part to a precision non-standard part made to your drawing, all inside the same cluster. The bad news is that “cheap to buy” is not the same as “right to buy.” Cheap springs are sold by the thousand; correct springs are engineered, tested and documented. Both come from China, and telling them apart is what the rest of this guide is for.
Demonstration of the Extension Springs Production Process Video
Buying springs is different from buying most goods because there are two fast decision forks, and getting either one wrong wastes most of what you do afterward. Take the time to answer both before a single quote lands in your inbox.
If you want to test demand fast, start with stock — standard parts the factory already makes, at most a color or surface-finish tweak. Stock is the cheapest way to put springs in front of your customers and learn what actually sells. If you want your own brand, or your application needs a size nobody carries, you go OEM/ODM custom — built to your drawing or sample. The two paths have completely different MOQs, lead times, pricing and inspection regimes, and I break each down in the material and pricing sections below. The rule that saves most beginners: test with stock first, customize only after the numbers justify it.
Ask one question first: what environment does this spring live in? Normal indoor air, humid coastal air, engine heat, or exposure to chemicals? Environment drives material, material drives price and service life. A music-wire spring that is perfect inside a desk lamp will rust in a year on a boat. Sort this line out before you compare quotes — otherwise you are comparing springs that are not the same part at all, and the cheapest one wins for the wrong reason.
The common extension-spring materials are few, and each has its own temperament. There is no “best” material, only the right one for your load and your environment, and the table below is the one buyers should keep handy.
Material | What it does | Typical use | FOB reference |
Music wire (high-carbon) | High strength, cheap, good springback | Small springs, normal environments | Lowest |
302/304 stainless | Corrosion-resistant, bright finish | Electronics, appliances, outdoor | Mid |
316 stainless | Stronger corrosion resistance, marine-grade | Marine, medical, chemical | Higher |
Oil-tempered spring steel | Long fatigue life, built for bigger parts | Auto suspension, farm machinery | Higher |
Galvanized steel | Cheap, surface protection | Garage doors, trampolines, garden tools | Low |
The one-line rule: if you can pin down the environment and just want to save money, use music wire or galvanized; if it runs damp or rust worries you, start at 304; if it must survive years of cycling, oil-tempered; if it faces marine or aggressive media, 316. Two practical warnings before you order. First, put the exact grade in the contract and ask for a material certificate — the same discipline as writing “304, not 201” on a bottle order, because a supplier who swaps a cheaper wire under the same name saves himself a few cents and costs you a field failure. Second, remember that surface finish is not the same as material: a bright galvanized spring can look stainless in a photo, and only the certificate tells you what you actually bought.
Extension springs in black e-coat, galvanized and yellow-zinc finishes — finish follows the environment
If your application is safety-critical — a brake pedal return, a trampoline frame, a latch — go a step further and ask whether the supplier can run a fatigue or salt-spray test on a sample batch, and whether they can provide the result. Springs fail in two ways: they take a set and stop returning, or they fracture after cycling. Both are invisible in a listing photo and both show up in a test a good factory can run in a day. A supplier who cannot document either is a supplier for a decorative product, not a load-bearing one.
Do not order before you confirm you actually need an extension spring and not a different type. This is the category’s most expensive trap — they all look like springs to a non-engineer, and the wrong type scraps the whole mechanism.
Spring type | How it loads | Typical shape | Typical use |
Extension spring | Resists a pull, pulls back when stretched | Closed coils + hooks/loops | Garage doors, trampolines, throttle return, washing machines |
Compression spring | Resists a push, pushes back when compressed | Open coils | Suspension, valves, buffers |
Torsion spring | Resists a twisting moment | Wound around an axis | Hinges, clamps, garage torsion bars |
A fast way to tell them apart: look at the coils when the part is unloaded. An extension spring has coils pressed together with no visible gap; a compression spring shows gaps between coils. If your application applies a pulling force, you want the closed-coil part; if it applies a pushing force, you want the open one; if the force is rotational, you are in torsion territory. Get the spring rate right and the whole mechanism works; get it wrong and the order is scrap. That is an engineering problem, not a price problem — solve it before you shop, and write the spring type on the inquiry so every quote you get is for the same class of part.
Extension, compression and torsion springs side by side — pick the type that matches the force
For a custom spring, three numbers on the spec sheet matter most. The table spells out what each one is and why it moves both performance and price.
Parameter | What it is | Why it matters |
Wire diameter | Thickness of the spring wire | Thicker wire carries more load and costs more |
Spring rate | Force needed per unit of stretch | Sets the mechanism’s feel and load |
Initial tension | Preload holding the coils together | Coils only separate once you exceed it |
Free length / outside diameter | Size | Defines the mounting space |
End hook / loop style | How the end attaches | Sets how the load connects |
When you write to a supplier, spell out these parameters, add a drawing or a physical sample, and it beats a hundred lines of “I want something better.” Two details most buyers skip. First, spring rate and wire diameter are linked — a thicker wire means a stiffer spring, so if your application needs a specific feel, decide the rate first and let the supplier size the wire to it. Second, initial tension is invisible until the part is in your hand; a spring with the wrong preload feels loose even when the dimensions match perfectly. Translation bends technical specs, so verify every item — written numbers survive the trip from Chinese to English far better than adjectives ever do.
Before you commit to a batch, order samples and check them with tools, not your eyes. A digital caliper confirms the wire diameter and free length in seconds, and a simple spring tester, or even a hanging weight and a ruler, confirms whether the rate matches the drawing. Lay the samples from two suppliers side by side and compress or stretch them the same way; the difference in feel tells you more than any quote sheet. And keep the golden sample after sign-off — it is the only objective standard that protects you when the bulk arrives and looks “close but not quite.”
Materials testing machine in a testing laboratory — verify springs with tools, not eyes
Price swings widely with material, wire diameter, order ladder and whether it is stock or custom. The ranges below are what the market actually showed in 2026 sourcing data.
Buying route | Reference price | MOQ | Note |
Stock standard (1688) | from ¥1.08/pc (304, open hook, 2000+) | 500–2000 | Fastest for volume |
Custom non-standard (1688) | from ¥5.00/pc | 10–1000 | To drawing or sample |
316 stainless custom (Alibaba) | ¥0.67–1.67/pc | 100 | Corrosion resistance |
Galvanized stock (Alibaba) | $0.06–0.10/pc | 500 | Surface protection |
Overall stock/custom (Made-in-China) | $0.006–3.00/pc | 10–1000 | Widest coverage |
Two rules to carry. First, ask for the ladder price — “what are the prices at 500, 2,000, 5,000 and 20,000 pieces?” — never just “how much per piece.” A supplier who only gives you a single unit price has not thought about your volume, and you can almost always find a better tier by asking. Second, ask whether the quote includes tax and local delivery to the port, so nothing gets added later. And add a third habit that separates professionals from hobbyists: work out landed cost, not just FOB. Freight, duty and inspection on a low-value part can double its real price, and the cheapest spring at the factory is not always the cheapest spring in your warehouse. Cheap is not a sin; chasing cheap is.
The Chinese spring industry divides labor clearly, so pick the region that fits the order instead of hunting the lowest quote nationwide.
Region | Positioning | Strength | Best for |
Guangdong (Jiangmen/Foshan/Dongguan/Shenzhen) | Precision-spring hub | Full supply chain, tight tolerances, export experience | Custom non-standard, precision parts, export |
Xiamen, Fujian | Hardware & precision springs | Good cost control, OEM-savvy | Mid-volume OEM |
Hangzhou, Zhejiang | Auto-parts cluster | Auto supply chain | Auto springs |
Ganzhou, Jiangxi | Absorbing coastal transfer | Low labor cost, vertical chain building out | Mid-low-end volume |
When you shortlist factories, do not judge from a quote sheet alone. Spend ten minutes in the workshop. Are the coiling machines running or sitting idle? Are the molds and dies numbered and maintained? Is the QC bench actually used, with inspection records you can flip through? Does the floor have oil everywhere or is it swept? A shop too lazy to wipe the oil off the floor is not one you expect to hold your tolerances. Springs fail on fatigue and dimension, and both are decided in the workshop long before the part ships. A real factory can show you a hardness tester and a spring-load tester; a trading desk that resells someone else’s stock usually cannot.
One more vetting habit that pays off: ask for a short factory video of the coiling line running your type of part, and a close-up of the load tester reading. A live clip is far harder to fake than a logo on a website, and it tells you whether the shop is making springs or just marketing them. Cross-check the video against the address and phone on the business license; if the details do not line up, treat that as a red flag and move on.
Precision spring workshop in Guangdong — judge the factory in the workshop, not the quote
Beyond choosing the spring, this is the other big fork. For an engineered component like an extension spring, whether to use an agency depends on what your time is worth, how big the orders are, and how much risk you want to carry. The honest answer is that neither route is always right; the right one depends on your situation.
Dimension | Direct from factory | Using an agency |
Paper cost | Lowest (no fee), high hidden costs | A service fee, low hidden costs |
Communication | Slow — language, time zones, distortion | Fast — the agency talks to factories in Chinese |
Quote accuracy | Hard to judge, padded quotes common | Knows the market, pushes quotes near the floor |
Inspection | Almost none unless you fly over | Core value: on-site checks, line follow-up |
After-sales | You argue alone | A supplier ledger and dispute handling |
The verdict: if you are a veteran moving dozens of containers a year with someone on the ground in China, direct sourcing leaves you the most margin. If you are new, your orders are mid-sized, or you have already been burned by language and inspection, a transparent-fee agency is often cheaper on total cost — the price it negotiates off the factory usually exceeds what it charges. The single most important thing to check with any agency is fee transparency: can you see the original factory invoice, is the commission separate from the factory price, and is inspection actually performed on the line? An agency that hides its markup is just an expensive middleman.
A small order is not a scaled-down big one; it is a different business. For a small test run (100–1,000 pieces), buy stock or a re-branded shell, ship by courier or air, and skip sea LCL — the fixed fees eat your margin. Even on a small order, arrange one inspection or you are not testing real quality; a sample that passes in a photo can arrive with hooks bent and coils sprung. For bulk (5,000+ pieces or a full container), go OEM/ODM, put the spec in the contract, sign a physical golden sample that becomes the only acceptance standard, split payment as 30% deposit with the balance after inspection, and book FCL two to three weeks ahead. Between the two, most buyers who treat a test order as a miniature version of a big order — same paperwork, same inspection, same payment discipline — come out ahead, because they learn the supplier before they commit the capital.
A1. Stock standard parts usually start at 500 pieces, and some factories ship from 200; custom non-standard parts can go down to 10–100 pieces depending on wire diameter and process complexity (2026 market levels).
A2. Judge by environment. For dry indoor use on a budget, music wire or galvanized; for damp or outdoor use where rust matters, start at 304; for marine or aggressive environments, use 316. Put the grade in the contract and request a material certificate.
A3. The rate sets the mechanism's feel and load. A wrong figure means at best a stiff or loose mechanism, at worst a scrap batch — it is an engineering decision, so fix the drawing before you fix the price.
A4. Non-standard parts typically sample in 3–7 days, then bulk production runs 15–25 days, depending on wire diameter and hook complexity. Lead times stretch noticeably during peak season or around Chinese New Year.
A5. Steel springs fall under HS 7320: helical springs under 732020, and other springs under 73209090. Classify by material and function, and confirm with customs — a wrong code can hold or fine a shipment.
A6. Direct looks cheaper on paper, but inspection, communication and after-sales are hidden costs. For mid-sized orders, a transparent-fee agency is usually cheaper on total cost — what it negotiates off the factory price often beats its fee. For big orders, veterans with people in China, direct wins on margin.
From MOQs and factory verification to shipping timelines and quality control, we’re here to help you source with confidence.
Not sure where to start? Let’s talk about your sourcing needs — no pressure, just honest advice from China-based experts.
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