{"id":2579,"date":"2026-07-01T06:03:33","date_gmt":"2026-07-01T06:03:33","guid":{"rendered":"https:\/\/hydrauliccylindersprice.com\/product\/mobile-crane-outrigger-expansion-cylinder\/"},"modified":"2026-07-01T06:03:33","modified_gmt":"2026-07-01T06:03:33","slug":"mobile-crane-outrigger-expansion-cylinder","status":"publish","type":"product","link":"https:\/\/hydrauliccylindersprice.com\/sk\/product\/mobile-crane-outrigger-expansion-cylinder\/","title":{"rendered":"Mobile Crane Outrigger Expansion Cylinder"},"content":{"rendered":"

<\/p>\n

<\/p>\n

\n \"Mobile<\/p>\n
\n Mobile Crane Cylinder<\/span><\/p>\n

Mobile Crane Outrigger Expansion Cylinder<\/h2>\n

The smallest bore in the family \u2014 but it determines the crane’s stability footprint. This cylinder slides the outrigger beam horizontally outward, placing the pad 2.5 metres further from the chassis before the vertical outrigger cylinder pushes it into the ground. Wider footprint = more load capacity.<\/p>\n

\n
50\u201375mm<\/span>Smallest Bore<\/span><\/div>\n
\u22642,500mm<\/span>Stroke<\/span><\/div>\n
35 MPa<\/span>Pressure<\/span><\/div>\n
\u00d74<\/span>Per Crane<\/span><\/div>\n<\/p><\/div>\n<\/p><\/div>\n<\/section>\n

<\/p>\n

\n

Two Cylinders, Two Directions \u2014 The Outrigger Pair<\/span><\/h2>\n

\"Outrigger<\/p>\n

\n \"Mobile<\/p>\n

Each outrigger assembly on a mobile crane uses two cylinders working in sequence. The expansion cylinder (#21) moves first \u2014 sliding the outrigger beam horizontally outward from the chassis to maximise the distance between opposite pads. Then the outrigger cylinder<\/a> (#19) moves second \u2014 extending vertically downward from the end of the beam to press the pad into the ground.<\/p>\n<\/div>\n

The expansion cylinder has the smallest bore in the crane cylinder family (50\u201375 mm) because its job is motion, not force. It only needs to overcome the friction of the beam sliding in its guide channel \u2014 the beam slides horizontally on wear pads, and the resistance is modest (a few kilonewtons). The large outrigger cylinder (#19, up to 360 mm bore) handles the heavy force \u2014 supporting the crane’s weight vertically.<\/p>\n

This separation of horizontal motion (small cylinder, long stroke) and vertical force (large cylinder, short stroke) is the standard architecture for mobile crane outrigger systems. Korea Ever-Power manufactures both cylinders as a matched pair within the mobile machinery hydraulic cylinder<\/a> range.<\/p>\n

<\/div>\n<\/section>\n

<\/p>\n

\n

Technical Specifications<\/span><\/h2>\n
\n\n\n\n\n\n\n\n\n\n\n\n\n
Parameter<\/th>\nSpecification<\/th>\n<\/tr>\n<\/thead>\n
Product<\/td>\nMobile Crane Outrigger Expansion Cylinder<\/td>\n<\/tr>\n
Function<\/td>\nExtend the outrigger beam horizontally<\/td>\n<\/tr>\n
Bore Diameter<\/td>\n50 mm \u2013 75 mm<\/td>\n<\/tr>\n
Rod Diameter<\/td>\n25 mm \u2013 55 mm<\/td>\n<\/tr>\n
Stroke<\/td>\n\u2264 2,500 mm<\/td>\n<\/tr>\n
Working Pressure<\/td>\nMaximum 35 MPa<\/td>\n<\/tr>\n
Application<\/td>\nMobile Crane (outrigger beam extension)<\/td>\n<\/tr>\n
Certification<\/td>\nISO 9001 \u00b7 100% hydrostatic tested<\/td>\n<\/tr>\n<\/tbody>\n<\/table><\/div>\n<\/section>\n

<\/p>\n

\n
\n

Wider = Safer \u2014 How 2.5 Metres of Horizontal Extension Increases Lifting Capacity<\/h2>\n

A crane’s resistance to tipping is proportional to the distance between the outrigger pads. Doubling the outrigger span roughly doubles the stabilising moment \u2014 which means the crane can lift proportionally more load at the same radius. The expansion cylinder’s 2,500 mm stroke can increase the outrigger span from the retracted (chassis-width) position to the fully extended position by up to 5 metres (2,500 mm per side \u00d7 2 sides).<\/p>\n

\n
\n Retracted: minimum stability<\/strong><\/p>\n

With the outrigger beams retracted (for road travel within legal width limits), the outrigger pads are positioned close to the chassis \u2014 typically 2.5\u20133.5 metres apart. This narrow footprint provides minimal stability and severely limits the crane’s lifting capacity. Many crane load charts show zero or minimal capacity at retracted outrigger position.<\/p>\n<\/p><\/div>\n

\n Fully extended: maximum stability<\/strong><\/p>\n

With both expansion cylinders fully extended, the outrigger span reaches 7\u20138.5 metres \u2014 more than double the retracted width. This wide footprint maximises the stabilising moment and unlocks the crane’s full rated capacity. The load chart’s “fully extended outrigger” column shows the highest permitted loads \u2014 every crane operator aims for full extension on every lift.<\/p>\n<\/p><\/div>\n

\n Partially extended: reduced capacity<\/strong><\/p>\n

When site constraints prevent full extension (adjacent buildings, traffic lanes, excavations), the expansion cylinder extends only partway. The load chart provides intermediate capacity columns for partial extension. The cylinder’s stroke sensor reports the actual extension percentage to the crane’s moment limiter, which automatically selects the correct capacity column. Contact the Korea Ever-Power engineering team<\/a> for outrigger expansion specifications.<\/p>\n<\/p><\/div>\n<\/p><\/div>\n<\/p><\/div>\n<\/section>\n

<\/p>\n

\n \"Crane
\n<\/section>\n

<\/p>\n

\n

2,500 mm Stroke from a 50\u201375 mm Bore \u2014 Engineering a Slender Cylinder<\/span><\/h2>\n

The expansion cylinder has an extreme length-to-diameter ratio \u2014 2,500 mm stroke from a 50\u201375 mm bore produces a retracted cylinder length of approximately 3,000 mm with an outer diameter of only 80\u2013100 mm. This slender proportions creates two engineering challenges that Korea Ever-Power addresses in the cylinder design:<\/p>\n

\n
\n Rod buckling under retraction force<\/strong><\/p>\n

When retracting the outrigger beam (pulling it back toward the chassis), the rod is in tension \u2014 no buckling risk. But during extension, the rod is in compression as it pushes the beam outward. At 2,500 mm extension with a 25\u201355 mm rod, buckling analysis is mandatory. Korea Ever-Power verifies the rod’s Euler buckling capacity at full extension, with the safety factor required by the crane’s structural design code.<\/p>\n<\/p><\/div>\n

\n Rod guide bearing length for side-load resistance<\/strong><\/p>\n

The outrigger beam can weigh 200\u2013500 kg. When the expansion cylinder is fully extended, the beam’s weight applies a bending moment at the rod guide (the bearing at the cylinder’s head where the rod exits). An undersized guide allows the rod to cock sideways \u2014 creating uneven seal wear and premature leakage. Korea Ever-Power specifies an oversized guide bearing length (\u22651.5\u00d7 bore diameter) to distribute the side load across a larger bearing surface.<\/p>\n<\/p><\/div>\n<\/p><\/div>\n<\/section>\n

<\/p>\n

\n

Manufacturing Process<\/span><\/h2>\n
\n \"Korea<\/p>\n

The small bore (50\u201375 mm) is honed to Ra 0.2\u20130.4 \u00b5m. Rod straightness is verified to \u22640.1 mm\/metre over the full 2,500 mm length \u2014 critical for preventing seal damage during retraction of a long, slender rod. Chrome plating is 50\u201380 \u00b5m (outdoor service with exposure to road splash and construction site debris).<\/p>\n<\/div>\n

Seals are polyurethane piston seal + NBR rod seal + double-lip wiper, rated for -30 \u00b0C to +80 \u00b0C. The position-locking function (holding the beam at a set extension) uses a pilot-operated check valve on the extend port \u2014 preventing the beam from creeping inward under vibration or incidental contact during crane operation.<\/p>\n

Every expansion cylinder is hydrostatic tested at 1.5\u00d7 rated pressure (52.5 MPa) and stroke-tested for smooth full extension and retraction without stick-slip \u2014 verifying that the long, slender rod travels straight and the seals function correctly over the entire 2,500 mm travel range.<\/p>\n<\/section>\n

<\/p>\n

\n

OEM & ODM<\/span><\/h2>\n
\n
\n
What You Provide<\/strong><\/div>\n
\n

Outrigger beam weight and length, required horizontal extension (stroke), beam guide channel cross-section (for cylinder envelope fit), retracted position constraint (for road-legal width), system pressure, position sensor requirement, and the outrigger beam assembly drawing showing the cylinder mounting and beam guide geometry.<\/p>\n<\/div><\/div>\n

\n
What the Factory Delivers<\/strong><\/div>\n
\n

Engineering drawing with bore, rod (buckling-verified), stroke, oversized guide bearing, position-lock valve provisions, seal specification, chrome plating detail, and mounting dimensions. Hydrostatic + full-stroke functional test. Seal kits. Browse the industrial engineering cylinders<\/a> and the complete Korea Ever-Power hydraulic cylinder catalogue<\/a>.<\/p>\n<\/div><\/div>\n<\/p><\/div>\n

\"Korea
\n<\/section>\n

<\/p>\n

\n

FAQ<\/span><\/h2>\n
\n
\n

Does the expansion cylinder carry any of the crane’s weight?<\/h3>\n

No \u2014 the expansion cylinder only provides horizontal motion. Once the beam is extended and the vertical outrigger cylinder (#19) pushes down, the crane’s weight is transferred vertically through the outrigger beam structure \u2014 bypassing the expansion cylinder entirely. The expansion cylinder remains extended but unloaded during lifting. Its only job is to position the beam before the vertical cylinder takes over.<\/p>\n<\/p><\/div>\n

\n

Can the operator extend one side more than the other?<\/h3>\n

Yes \u2014 asymmetric outrigger extension is common when one side of the crane is blocked by a wall, a trench, or traffic. The crane’s moment limiter (load chart computer) monitors each expansion cylinder’s position independently and calculates the reduced stability envelope for the asymmetric footprint. The load capacity is limited by the most restrictive (narrowest) side.<\/p>\n<\/p><\/div>\n

\n

Why is the expansion cylinder separate from the vertical outrigger cylinder?<\/h3>\n

Because the two motions require very different cylinder specifications. Horizontal extension needs long stroke (2,500 mm) and low force (only beam friction) \u2014 a small-bore, slender cylinder. Vertical support needs short stroke (800 mm) and massive force (the crane’s full weight) \u2014 a large-bore, heavy-wall cylinder. Combining both into one cylinder would compromise both functions. Browse telescopic cylinders<\/a> and aerial work vehicle cylinders<\/a> for similar two-cylinder stabilisation systems.<\/p>\n<\/p><\/div>\n<\/p><\/div>\n<\/section>\n

<\/p>\n

\n

Related Categories<\/span><\/h2>\n
\n <\/p>\n
\n
\"Telescopic\"<\/div>\n
\n
Telescopic Hydraulic Cylinders \u2192<\/div>\n
Dump truck, trailer, hoist.<\/div>\n<\/div>\n<\/div>\n

<\/a>
\n <\/p>\n

\n
\"Forklift\"<\/div>\n
\n
Forklift Hydraulic Cylinders \u2192<\/div>\n
Lift, tilt, steer \u2014 OEM.<\/div>\n<\/div>\n<\/div>\n

<\/a>
\n <\/p>\n

\n
\"AWV\"<\/div>\n
\n
Aerial Work Vehicle Cylinders \u2192<\/div>\n
Scissor, boom, platforms.<\/div>\n<\/div>\n<\/div>\n

<\/a>\n <\/div>\n<\/section>\n

<\/p>\n

<\/main><\/p>","protected":false},"excerpt":{"rendered":"

Mobile crane outrigger expansion cylinder \u2014 the horizontal actuator that slides the outrigger beam outward from the crane chassis, positioning the outrigger pad as far from the machine centreline as possible before the vertical outrigger cylinder (#19) pushes the pad down to the ground. Wider outrigger span = larger stability footprint = higher permitted lifting capacity. The smallest bore in the mobile crane family (50\u201375 mm) because this cylinder only moves the beam \u2014 it does not carry the crane’s weight. Stroke \u22642,500 mm, 35 MPa. Korea Ever-Power. ISO 9001. OEM & ODM.<\/div>","protected":false},"featured_media":2580,"comment_status":"closed","ping_status":"open","template":"","meta":{"_et_pb_use_builder":"","_et_pb_old_content":"","_et_gb_content_width":""},"product_brand":[],"product_cat":[854],"product_tag":[],"class_list":["post-2579","product","type-product","status-publish","has-post-thumbnail","product_cat-mobile-machinery-hydraulic-cylinders","pa_editor-cxm","first","instock","product-type-simple"],"_links":{"self":[{"href":"https:\/\/hydrauliccylindersprice.com\/sk\/wp-json\/wp\/v2\/product\/2579","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/hydrauliccylindersprice.com\/sk\/wp-json\/wp\/v2\/product"}],"about":[{"href":"https:\/\/hydrauliccylindersprice.com\/sk\/wp-json\/wp\/v2\/types\/product"}],"replies":[{"embeddable":true,"href":"https:\/\/hydrauliccylindersprice.com\/sk\/wp-json\/wp\/v2\/comments?post=2579"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/hydrauliccylindersprice.com\/sk\/wp-json\/wp\/v2\/media\/2580"}],"wp:attachment":[{"href":"https:\/\/hydrauliccylindersprice.com\/sk\/wp-json\/wp\/v2\/media?parent=2579"}],"wp:term":[{"taxonomy":"product_brand","embeddable":true,"href":"https:\/\/hydrauliccylindersprice.com\/sk\/wp-json\/wp\/v2\/product_brand?post=2579"},{"taxonomy":"product_cat","embeddable":true,"href":"https:\/\/hydrauliccylindersprice.com\/sk\/wp-json\/wp\/v2\/product_cat?post=2579"},{"taxonomy":"product_tag","embeddable":true,"href":"https:\/\/hydrauliccylindersprice.com\/sk\/wp-json\/wp\/v2\/product_tag?post=2579"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}