---
title: "Single vs Double Girder Overhead Crane: How to Choose"
url: https://yzcranes.com/single-vs-double-girder-overhead-crane-how-to-choose/
date: 2026-09-02
modified: 2026-08-29
lang: en
author: "liudatou"
description: "The rule fits in one line. Below 20 tons, medium-to-low frequency and generous headroom call for a single girder. Above 20 tons, high-frequency heavy duty or tight headroom points to..."
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word_count: 2164
---

# Single vs Double Girder Overhead Crane: How to Choose

The rule fits in one line. Below 20 tons, medium-to-low frequency and generous headroom call for a single girder. Above 20 tons, high-frequency heavy duty or tight headroom points to a double girder. A need for an auxiliary hook and maintenance platform also points to double. The single girder is cheap, light, and gentle on the building. The double girder, meanwhile, offers more capacity, better headroom use, and longer life. Neither is strictly better than the other, only better matched to the job. Pick the wrong structure and buyers waste money. Or they take delivery of a machine that cannot lift high enough or cycle fast enough.

## What Is a Single Girder Overhead Crane

A single girder overhead crane rides on one main girder. The electric hoist travels along the girder's lower flange or a top rail. The crane itself runs on the runway beams along both sides of the building. Mainstream capacity covers 0.5 to 20 tons, with 10 and 16 tons the most common specs in machining shops.

### How Single Girders Pay Off

Simple structure brings direct benefits. The complete machine stays light, and wheel loads run small. Demands on the runway and foundations stay low too. Both purchase price and installation cost therefore come in a notch lower. European single girders build the hoist into a low-headroom arrangement, so the hook reaches higher and the whole package looks more compact. VFD-controlled models start and stop smoothly, and operators learn them quickly.

### Where Single Girders Fall Short

The limits are just as clear. Past 20 tons of capacity, girder sag and stiffness get hard to manage without losing economy. The hoist hangs on the side of the girder, leaving a wide dead zone on both sides of the hook. Loads tight against the wall then sit out of reach. Duty class tops out around A5, and long-term full-load, high-frequency work speeds up mechanism aging. The best fit is machining, warehousing, and light assembly. These are shops that run a few to a few dozen lifts a day and rarely see full load.

Inside the single girder category sit European and conventional versions. The conventional LD type weighs more and leaves the hook limit lower, with price as its main edge. The European single girder uses a steel box girder and a low-headroom hoist. That design cuts weight by over 20 percent and shrinks wheel loads. New buildings can then design columns and foundations around lower runway loads, and the civil savings sometimes cover the equipment price gap. That difference deserves a place in the math from the very start of selection.

## What Is a Double Girder Overhead Crane

A[ double girder overhead crane](https://yzcranes.com/product/lhb20-5t-explosion-proof-double-girder-overhead-crane-with-hoistlhb20-5t/) runs two main girders, with the trolley also traveling on rails atop both. Capacity covers 5 to 500 tons, and 10, 32, and 50 tons are the common ratings found in shops.

### What the Second Girder Buys

That extra girder buys a great deal. The trolley sits on top of the beams, so the hook can rise up between the two girders. It gains 1 to 2 meters of lifting height at the same building height, which is real value in headroom-tight old plants. The trolley can also travel close to the girder ends, shrinking the hook dead zone and strengthening edge-of-room work. A maintenance platform can be laid on the girders and an operator cabin mounted, so service crews never have to work suspended in midair. Duty class reaches A6 to A8. With main and auxiliary hooks, the machine handles three-shift work in foundries, heavy assembly, shipyards, and steel structure shops.

Double girders also accommodate process expansion better. Grabs, electromagnetic lifting magnets, and container spreaders are heavy below-hook devices. These only sit securely on a double girder trolley. When two trolleys must tandem-lift long or oversized pieces, the double girder platform is the standard carrier.

The auxiliary hook is another common reason to go double. The main hook handles heavy tonnage, while the aux hook runs quick 3 to 5 ton light lifts. Small jobs then never wake the main mechanism. Efficiency and energy use both improve. A rough rule of thumb helps here. Above 16 tons, a shop running plenty of light auxiliary lifts every day pays back fast. The extra cost of an aux hook usually returns within one to two years through efficiency.

### The Tradeoff and Its Price

The tradeoff is plain. Double girders weigh more and push wheel loads higher. They demand more from the building structure, and they cost more in both equipment and foundation investment. Whether that extra girder earns its keep depends on the answers to the next three questions.

## Head-to-Head Comparison

| Comparison Point | Single Girder Overhead Crane | [Double Girder Overhead Crane](https://yzcranes.com/product/lhb20-5t-explosion-proof-double-girder-overhead-crane-with-hoistlhb20-5t/) |
| ---------------- | ---------------------------- | -------------------------------------------------------------------------------------------------------------------------------------- |
| Common capacity | 0.5-20 tons | 5-500 tons |
| Relative cost | Low, about 60%-75% of double at same tonnage | High, includes trolley and maintenance platform structure |
| Building headroom use | Hook sits below girder, takes more height | Hook rises between girders, saves 1-2 m of headroom |
| Hook limit position | Hoist hugs girder side, wide dead zones | Trolley nears girder ends, small dead zones |
| Duty class (FEM) | Usually A3-A5 | Up to A6-A8 |
| Maintenance difficulty | Low, hoist is a standardized module, quick to swap | Medium, drive service needs the girder platform |
| Design life | 15-20 years in light-medium duty | 20-30 years, more durable in heavy duty |

Think of choosing a girder type like choosing a vehicle for the household. A compact car handles commuting and errands with agility and fuel economy. Hauling heavy loads up mountain roads every day, by contrast, calls for a work truck. Sending the compact car to haul tile piles wears it out and turns the job dangerous.

The cost gap reaches beyond the machine itself. Double girders carry bigger wheel loads, so runway beams and brackets must be designed for larger forces. Civil costs rise in step on new buildings. On the other hand, a headroom-tight site that picks a European double girder saves 1 to 2 meters of height. That saving can drop the whole building one story class and earn the money back in civil work. Equipment selection and building design therefore belong on the same drawing.

## Three Questions Settle the Choice

### Question 1: Heaviest Lift and Future Growth

**Question one: What is the heaviest lift, and will it get heavier?** A current heaviest piece of 15 tons with a planned 32-ton machining center within two years argues for going double now rather than replacing equipment later. When tonnage regularly tops 20 tons, stop hesitating and choose double.

### Question 2: Available Building Headroom

**Question two: How much building headroom is available?** The real usable lifting height is the height from floor to truss lower chord minus the height the equipment occupies. A plant under 9 meters of clear height lifting pieces over 6 meters tall often finds only one answer: the European double girder low-headroom trolley. In a generous new building, the value advantage of a single girder finally has room to work.

### Question 3: Usage Frequency and Duty

**Question three: How high is the usage frequency?** Up to 20 lifts a day with a load ratio below 50 percent is well inside a single girder A4-A5 comfort zone. A dozen cycles an hour, high full-load rates, and two or three shifts demand a double girder at A6 or above. Without it, the gearbox, brakes, and wire rope fail in a cluster within three to five years. By then, one overhaul plus the downtime quote often equals the entire price gap between single and double in the first place.

### Real Projects Test the Answers

Check the questions against a real project. A heavy machinery shop had 11 meters of clear height, a 45-ton heaviest workpiece, two shifts a day, and about 80 lifts daily. The three answers, 45 tons, medium headroom, and high-frequency heavy duty, pointed one way: a 32 or 50-ton double girder with main and aux hooks. Forcing a 20-ton single girder to fit the early budget would have brought girder fatigue and a capacity bottleneck within three years. Flip the case to a precision-parts repair shop with an 8-ton heaviest piece, a dozen lifts a day, and 8.5 meters of headroom. A 10-ton European single girder is the optimal answer, and a double girder there is pure budget waste.

After the three questions, the conclusion surfaces on its own. Light, low, and idle goes single. Heavy, high, and busy goes double.

A few middle-ground conditions deserve their own callout. Past a 22.5 meter span, even at only 10 tons, single girder deflection gets hard to control, and many manufacturers recommend double. Jobs that frequently switch below-hook devices such as grabs and magnets find the double girder trolley's load and power supply arrangement more reliable. New buildings can move equipment selection forward into the design phase. That lets runway brackets be reserved for the target machine instead of constraining the choice after the walls go up. Gather the three "biggest" numbers, heaviest piece, busiest shift, and tallest workpiece, and the manufacturer's plan will not drift off target.

## Why Choose Yuzhong

The worst scenario in girder selection is a factory that builds only one structure. A single-girder seller always claims single is enough, and a double-girder builder wants every project fitted with double. Yuzhong (Henan Yuzhong Crane Group) began in 1978 and keeps its headquarters in Changyuan, Henan. The group carries 48 years of crane manufacturing history and keeps both girder types inside its own product system. European single girder cranes cover 0.5 to 20 tons, and double girder cranes cover 5 to 500 tons. The LHB explosion-proof double girder series covers 5 to 50 tons with ATEX/IECEx certification. Recommendations rest on duty data, not on which machine carries the higher margin.

Yuzhong commits to custom drawings within 24 hours. Once buyers provide load weight, work cycle rate, and a building cross-section, they get structural selection and headroom verification. The single-versus-double price gap and its reasoning are spelled out clearly too. Core components use Siemens motors and SKF bearings. The machines carry ISO system certification and meet FEM, ASME, and CE standards, and products ship to more than 120 countries with on-site installation guidance and full-life-cycle after-sales service. Hand the selection question to a builder who makes both girder types, and the answer has a real chance of being neutral.

## Frequently Asked Questions

### Is 20 tons a hard dividing line between single and double girder?

Not an absolute red line, but 20 tons is the industry-recognized economic turning point. Below it, single girder technology is mature and the price advantage is clear. Above it, the single girder and hoist need special reinforcement that pushes price near double girder levels, while capability and life still lag, so most manufacturers recommend switching. The final call still weighs span and duty class together, and a long-span 16-ton job sometimes goes straight to double.

### Does a double girder always last longer than a single girder?

Under equal maintenance, the double girder carries higher design redundancy and a higher duty class ceiling, so its life advantage in heavy duty is clear and commonly reaches 20 to 30 years. A double girder that sits idle or misses maintenance never gets to show that advantage, while a single girder used properly in light duty commonly reaches 15 to 20 years. Duty conditions and maintenance therefore carry more weight in lifespan than the structural form.

### The building is already up and headroom is short. What now?

First measure the effective height from floor to truss lower chord, then check the clearance the equipment needs. A European low-headroom single girder or European double girder trolley can save 0.5 to 2 meters over conventional structures. If that still falls short, consider a recessed rail or a semi-gantry arrangement. Sending the building cross-section to the manufacturer for headroom verification is a step that cannot be skipped before ordering, and the result should be checked against the tallest workpiece size.

### Can a single girder upgrade its duty class to handle high-frequency use?

Configuration can rise within limits, such as switching to hardened-gear reducers and VFD control. But single girder structural stiffness and hoist heat dissipation have ceilings. In continuous heavy duty above A6, even a single girder force-fitted with high-grade mechanisms still falls short on girder fatigue and wire rope life. When failures cluster within three to five years, repair bills plus downtime losses far exceed the original double girder price gap.

### The budget only covers a single girder, but the job nears double. What should buyers do?

Forcing it is not recommended. A crane's safety margin cannot be added after the fact, and overload plus fatigue damage convert directly into accident risk. Buyers can adjust the purchasing pace and install the double girder main structure first. They can also simplify non-critical items such as the operator cabin, or choose a reliable factory's standardized double girder package to control cost. A factory-direct model cuts out middleman markup and can match a safer structure to heavy duty within the same budget.