GPM, PSI, ROC, SSQA, high-flow, back pressure, displacement — every technical term you'll encounter when buying attachments in Canada, defined plainly and with context for what it actually means for your purchase.
Attachment spec sheets use a lot of abbreviations and technical terms without explanation. This glossary covers every term a Canadian buyer is likely to encounter — machine specs, hydraulic specs, structural specs, and attachment-specific terms. Organized alphabetically. Use the quick-jump navigation below.
The angle at which the bucket or blade can pivot away from the machine's travel direction. Higher angle of departure allows working in tighter spaces and improves material release when tilting the bucket to dump. On angled blades, this describes the maximum swing angle relative to the machine centerline.
Abrasion Resistant steel grades widely used for cutting edges, bucket lips, and wear surfaces. The number indicates approximate Brinell hardness (400 HB, 450 HB). Standard structural steel (A36) is around 120 HB — AR400 is more than three times harder. Hardox is a Swedish branded version of abrasion-resistant steel (Hardox 400, Hardox 450, Hardox 500) that has become a de facto quality standard reference in the industry.
The hydraulic circuit(s) dedicated to powering attachments — separate from the hydraulic circuits that actuate the boom, arm, and bucket tilt. Standard skid steers have one pair of auxiliary ports (supply and return). Some have two pairs or a dedicated third-function port. The aux circuit is what connects your machine to any hydraulically-powered attachment.
Resistance to fluid flow in the return line (from the attachment back to the machine's tank). Excessive back pressure means the attachment can't dump its return fluid fast enough, reducing effective output pressure at the motor or cylinder. Caused by undersized return hoses, clogged filters, or return line restrictions. High-flow attachments are particularly sensitive to return line back pressure.
Bobcat's proprietary quick attach system. Not compatible with SSL Universal (SSQA) attachments without an adapter plate. The Bob-Tach uses a specific engagement geometry — two locking levers (older design) or a cross-pin system (newer) — distinct from the universal standard. See our complete quick attach guide for full compatibility details.
The maximum force a bucket or blade can exert against the ground or material during the loading phase — specifically when the attachment curls or rotates into the material. Measured in kilonewtons (kN) or pounds-force (lbf). Higher breakout force allows the machine to penetrate harder material and fill the bucket more completely. Published by machine manufacturers, not attachment manufacturers.
The Canadian tax depreciation system for business assets. Attachments typically fall under CCA Class 10 (30% declining balance) or Class 8, depending on the asset type. Immediate Expensing provisions for Canadian-Controlled Private Corporations (CCPCs) may allow 100% deduction in the year of purchase on qualifying property. Tax treatment affects the effective cost of an attachment purchase — consult your accountant.
A rubber-tracked version of a skid steer loader. CTLs have lower ground pressure than wheeled skid steers, making them more suitable for soft or wet terrain. They share the same quick attach systems and hydraulic configurations as wheeled skid steers, and most attachments are compatible with both. CTLs are more prevalent in BC and Ontario landscaping due to their turf-friendliness, and in northern operations where track flotation matters. See also: SSL.
The volume of fluid required per revolution of a hydraulic motor, expressed in cubic centimetres per revolution (cc/rev) or cubic inches per revolution (cu in/rev). Higher displacement motors produce more torque at a given pressure but rotate more slowly per litre of fluid. Lower displacement motors spin faster but produce less torque. Relevant when evaluating hydraulic motor quality in auger drives, mulchers, and trenchers.
The dominant hydraulic quick-connect coupler type on modern skid steers. The coupler face is flush (flat), which minimizes contamination when connecting and disconnecting. Available in 1/2-inch and 3/4-inch body sizes. Standard on most modern North American machines. Incompatible with poppet-style couplers — they look different and won't seal with each other.
A hydraulic valve that splits one hydraulic circuit into two equal flows. Used when an attachment requires two balanced hydraulic inputs but the machine only has one aux circuit available. Flow dividers add complexity and can reduce efficiency — they're a workaround, not a first-choice solution. On a machine with a proper second aux port, a flow divider isn't needed.
For wheeled skid steers: the width of the machine between the outer faces of the rear drive wheels. Relevant for calculating how wide an attachment can be while maintaining visibility and clearance. Frame width affects which attachments create excessive overhang on narrow machines.
The volume of hydraulic fluid flowing from your machine to the attachment per minute. The single most important hydraulic specification for attachment selection. Standard flow skid steers: 15–20 GPM. High-flow machines: 28–45 GPM. Attachments list minimum GPM requirements — running an attachment below its minimum results in underpowered operation or failure to function.
Canadian units note: some Canadian spec sheets list L/min (litres per minute) instead of GPM. 1 GPM = 3.785 L/min. So a 30 GPM requirement = 113.6 L/min.
The downward force per unit area that the machine's tracks or tires exert on the ground. Measured in PSI or kPa. CTLs have much lower ground pressure than wheeled skid steers — typically 3–7 PSI vs 25–45 PSI — making them preferable on soft or turf surfaces. Relevant when selecting attachments for sensitive terrain in BC orchards, turf operations, or boggy northern sites.
A brand name for a range of abrasion-resistant wear steels made by SSAB (a Swedish steel producer). Hardox 400 (400 HB hardness), Hardox 450, and Hardox 500 are the most common grades in the attachment industry. Hardox has become a reference quality standard — attachments listing "Hardox construction" or "Hardox wear parts" signal a quality commitment, though you should still verify the grade used for specific components.
A hydraulic system option (standard on some machines, optional upgrade on others) that delivers higher GPM to the aux circuit — typically 28–45 GPM vs. 15–20 GPM for standard flow. High-flow is required for cold planers, large mulchers, high-capacity brooms, large disc mulchers, and other high-demand attachments. Not all machines can be retrofitted with high-flow; it's a factory option on most OEM machines.
A calculated measure of the power available at the attachment connection: HHP = (GPM × PSI) ÷ 1,714. Useful for comparing what different machine configurations can actually deliver to an attachment. A machine producing 20 GPM at 3,200 PSI delivers 37.3 HHP to the attachment. A high-flow machine at 40 GPM and 3,200 PSI delivers 74.6 HHP — double the power.
An international standard defining the geometry of skid steer loader quick attachment interfaces. In practice, ISO 24410 and SSQA (SSL universal) describe compatible geometry — attachments and machines complying with either should be interchangeable. Primarily relevant when dealing with European-manufactured equipment in Canada.
The mechanism by which GST/HST paid on business purchases is recovered in Canada. If your business is registered for GST/HST, the tax paid on equipment purchases (including attachments) is recoverable as an ITC against your GST/HST remittances. This reduces the effective cost of all equipment purchases by the applicable tax rate (5% GST federally, plus provincial component in HST provinces).
The metric equivalent of GPM for hydraulic flow. Canadian spec sheets from some manufacturers use L/min. Conversion: multiply GPM by 3.785 to get L/min. Standard flow machines: approximately 57–75 L/min. High-flow machines: approximately 106–170 L/min.
The maximum weight the machine can raise to full lift height. Often stated at both the "rated capacity" (with specified stability margin) and "tipping load" (the weight that would tip the machine). ROC is typically 35–50% of tipping load. Attachment weight counts against lift capacity — a heavier attachment reduces effective lift capacity for material you're moving.
Bobcat's internal designations for arm lift geometry. R-Series (radial lift path) — the arm traces an arc during lifting, reaching maximum forward reach at mid-height. Better for ground-level work, loading trucks, and operations where reach at mid-height matters. L-Series (vertical lift path) — the arm moves more vertically, maintaining forward reach through more of the lift range. Better for high-dump operations and pallet stacking. Determines which attachments and operations suit the machine.
The SI unit for pressure; the metric equivalent of PSI used in some Canadian and international spec sheets. 1 MPa = 145 PSI. A hydraulic system at 24 MPa delivers 3,480 PSI — within the normal operating range for skid steer attachments. If you see MPa on a spec sheet, multiply by 145 to get PSI.
The hydraulic pressure at which the machine normally operates its aux circuit — typically 2,800–3,500 PSI on most modern skid steers. Distinct from relief pressure (the maximum before the relief valve opens). Attachments list both minimum and maximum operating pressure — running an attachment above its maximum can damage seals and motors.
An older style of hydraulic quick-connect coupler that uses a spring-loaded ball or poppet valve to seal when disconnected. Identifiable by a slightly recessed center in the female (socket) side. Incompatible with flat-face couplers. Found on older machines and some older attachments. If you're buying used equipment from pre-2005 era, check coupler type.
The US/Canadian unit for hydraulic pressure in attachment specifications. Skid steer systems typically operate at 2,800–4,000 PSI at the aux circuit. This pressure, combined with GPM, determines the power available to the attachment (see: Hydraulic Horsepower). Attachments specify minimum and maximum operating pressure — the minimum ensures the attachment gets enough pressure to function; the maximum protects the attachment's hydraulic components.
The standardized mounting interface on the back of an attachment that engages with the machine's carrier. The plate geometry determines compatibility with the machine's quick attach system. See: SSQA, Bob-Tach, ISO 24410. The quick attach plate is the structural connection — it must be in good condition and properly engaged for safe operation.
The pressure at which the hydraulic system's relief valve opens to prevent overpressure damage. Distinct from operating pressure — the relief pressure is the ceiling, not the normal operating point. Most skid steers have aux circuit relief settings between 3,000–4,000 PSI. Some attachments (particularly hydraulic breakers) require the relief to be set within a specific range — some need it lower than the machine's factory default. Adjusting relief settings should be done by a qualified technician.
The maximum load a skid steer can handle at its rated stability margin — typically 35–50% of the machine's tipping load, depending on which standard the manufacturer uses. Attachment weight directly reduces your working ROC: if a machine has a 900 kg ROC and your attachment weighs 250 kg, you can only load 650 kg of material. This is the single most critical machine specification for attachment selection.
The North American industry body (now part of AEM, the Association of Equipment Manufacturers) that established the SSL universal quick attach standard. When people refer to the "universal quick attach" or SSQA standard, they're referring to SKMA's published specification for quick attach plate geometry. Compliance with SKMA standards is what makes attachments from one brand compatible with machines from another.
The generic category term for wheeled skid steer loaders. Used in standards documents (SSL universal quick attach) and regulatory contexts. In everyday conversation, "skid steer" and "SSL" are interchangeable for wheeled machines. CTLs (compact track loaders) share the SSL quick attach system but are technically a distinct category.
The North American standard quick attach plate geometry used by most skid steer manufacturers except Bobcat. When an attachment is listed as "universal" or "SSQA compatible," it means the mounting plate conforms to this standard. Case, Cat, John Deere, Kubota, New Holland, Takeuchi, Gehl, and ASV all use SSQA-compatible systems from the factory.
Standard flow: the basic hydraulic output of a skid steer's aux circuit, typically 15–20 GPM. High flow: an optional or standard higher-output configuration delivering 28–45 GPM. Many attachments run on standard flow; high-demand attachments (large mulchers, cold planers, high-capacity brooms) require high flow. Not all machines can be retrofitted. Attachment listings specify which is required.
A third independent hydraulic circuit, separate from the standard single aux pair. Enables attachments with two independent hydraulic functions — for example, a grapple that opens/closes (first function) AND rotates independently (second function). Not all machines have this; it's an option on many mid-size and larger skid steers. Required for rotating grapples, tilting buckets with hydraulic tilt, and some specialty attachments.
The weight that would cause the machine to tip forward, measured with the machine level on solid ground. ROC is a fraction of tipping load (typically 35–50%, depending on OEM standard). Attachment manufacturers sometimes list attachments in relation to tipping load — but ROC is the number you should actually use for working capacity calculations.
See: SSQA. "Universal" in the context of skid steer attachments refers specifically to the SKMA/SSL universal quick attach standard geometry. It does not mean "compatible with all machines" — it's incompatible with Bobcat Bob-Tach without an adapter. One of the most misleading terms in the industry.
A replaceable plate of hardened steel attached to high-wear areas of an attachment — bucket floors, side cheeks, grapple jaws. The wear plate sacrifices itself to protect the structural body. When the wear plate is consumed, you replace it instead of the whole attachment. Attachments with replaceable wear plates have significantly longer service lives than those without, making them more economical over time despite higher initial cost.
For blades, brooms, mulchers, and similar attachments: the width of the work area the attachment covers in a single pass. Distinct from overall attachment width, which includes mounting hardware and may be wider. A 72" snow pusher has a 72" working width; the overall attachment may be 74" including the frame. Always confirm the working width when sizing a blade or broom for a specific area (parking lot, trail, etc.).
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