Every spec sheet, dealer listing, and YouTube comment section uses terms that assume you already know what they mean. This glossary covers the most important ones — from ROC and tipping load to case drain, carbide teeth, and drum mulchers — in plain language for Canadian buyers.
The secondary hydraulic circuit on a skid steer that powers rotating or actuating attachments — augers, mulchers, brooms, grapple cylinders, and anything else beyond the lift and tilt of the loader arms themselves.
Auxiliary circuits come in two modes: single-acting (flow in one direction, spring return) and double-acting (flow and return both controlled — required for grapple open/close, 4-in-1 buckets, and attachments with multiple functions).
The key specs are flow (GPM) and pressure (PSI). Most modern machines deliver 3,000–3,500 PSI. Flow is where compatibility problems happen — see High Flow and Standard Flow.
Bobcat's proprietary quick-attach system. The attachment plate geometry is slightly different from the universal SSQA standard — the vertical receiver pockets are spaced and sized differently, and the bottom hooks have a distinct angle.
Many third-party attachments are sold with Bob-Tach-compatible plates. Some SSQA attachments will fit a Bobcat machine with minor force-fitting, but this is not guaranteed and can cause plate wear or unsafe seating. Always verify the plate type when buying.
See also: Bob-Tach vs Universal Quick Attach — Full Compatibility Guide →
Cutting inserts made from tungsten carbide — an extremely hard, wear-resistant compound — used on mulcher rotors, stump grinder wheels, trencher chains, and some bucket cutting edges. Carbide teeth are replaceable; they bolt or press into pockets on the rotor or cutting wheel and can be individually swapped when worn.
Two common designs:
Carbide tooth replacement is a normal maintenance item — most operators doing heavy clearing will budget for a set of teeth per season. Always source OEM or OEM-equivalent hardness carbide; cheap aftermarket teeth wear out much faster.
A third hydraulic line (in addition to the two work ports) required by some hydraulic motors — most commonly those on mulchers, forestry heads, and high-torque rotary tools. The case drain line returns internal leakage from inside the motor housing directly back to the machine's tank, bypassing the normal return circuit.
Why it matters: High-torque piston motors generate internal leakage as part of normal operation. If that leakage can't escape freely, it builds pressure inside the motor casing, blowing shaft seals and destroying the motor — often within a few hours of operation.
Check your machine's spec sheet under "case drain return" or call your dealer before running any forestry or mulching attachment that lists a case drain requirement. The cost of the kit is trivial compared to a motor replacement.
A loader that uses rubber (or steel) tracks instead of tires. CTLs use the same SSQA attachment system as wheeled skid steers, so attachments are largely interchangeable. The main differences that matter for attachments:
See also: Compact Track Loader vs Skid Steer — Which Is Right for Canadian Work? →
The replaceable steel bar across the bottom of a bucket. Cutting edges wear down from scraping against gravel, asphalt, frozen ground, and rock — and are designed to be replaced, not the whole bucket. Most heavy-duty buckets use bolt-on edges (typically 400 or 450 Brinell hardness steel).
Options include:
See also: Tooth Bar.
A mulching attachment that uses a large horizontal spinning disc (like a saw blade) with carbide or steel teeth to cut and chip brush and small trees. Disc mulchers cut low and close to ground level and handle very small-diameter material efficiently.
Compared to drum mulchers: disc mulchers are lighter, often run on standard or lower high-flow machines, and produce a coarser chip. They're better for light brush clearing and opening trails. They struggle with dense stands of material and larger-diameter stems — a 6" tree will slow a disc mulcher significantly where a drum mulcher handles it more easily.
See also: Drum Mulcher vs Disc Mulcher — Head-to-Head for Canadian Land Clearing →
A mulching attachment with a horizontal rotating drum (cylinder) studded with carbide teeth or hammers. The drum spins at high RPM and processes brush, saplings, and small trees into fine chips or mulch in a single pass.
Drum mulchers are the workhorse of Canadian land clearing, right-of-way maintenance, and acreage prep. Key advantages over disc mulchers:
The catch: Drum mulchers almost always require high flow hydraulics (28–45+ GPM). They're heavy (800–2,000+ lbs), and they need a case drain line on the motor. Running a drum mulcher on an underpowered machine is the most common way to destroy both the mulcher and the machine's hydraulic system.
See also: Mulcher Attachments → | Drum vs Disc Mulcher → | Shop Mulchers →
A mowing attachment that uses a horizontal rotor with small individual blades (flails) mounted on pivot pins. Unlike a rotary cutter's solid blade, flail blades are free to swing back on impact with a rock or obstacle — greatly reducing the risk of dangerous projectiles.
Flail mowers are the preferred mowing tool for:
They produce a finer cut and better mulching than rotary cutters but won't handle heavy brush the way a drum mulcher or open-front brush cutter can.
See also: Flail Mower Attachments →
A hydraulic mode where the lift circuit is relieved of pressure and the loader arms are free to follow the ground contour under their own weight and downward force. In float, the bucket or blade maintains contact with the ground without you actively controlling it.
Float is essential for:
Most modern skid steers have a dedicated float detent position on the lift control. If your machine doesn't have float or if it's not working correctly, finish grading and snow removal become significantly harder.
The volume of hydraulic oil your machine's auxiliary circuit delivers per minute. GPM is the primary compatibility spec for any hydraulic-powered attachment.
| Machine Class | Standard Flow | High Flow (if equipped) |
|---|---|---|
| Mini skid steer (<2,000 lb) | 8–12 GPM | Usually not available |
| Compact (2,000–5,000 lb) | 14–18 GPM | Sometimes optional |
| Mid-frame (5,000–7,500 lb) | 17–22 GPM | Optional on most brands |
| Large / CTL (7,500+ lb) | 20–24 GPM | 34–45 GPM |
Always match attachment GPM requirements to your machine's output. Running a high-demand attachment on insufficient flow will result in underperformance and accelerated motor wear. See also: High Flow, Standard Flow.
An attachment with hydraulic-powered clamping tines or jaws for grabbing, sorting, and moving material. Grapples require double-acting auxiliary hydraulics to open and close.
Main grapple types for skid steers:
See also: Grapple Attachments → | Shop Grapples →
An enhanced auxiliary hydraulic circuit found on larger or optioned skid steers and CTLs, delivering 28–45+ GPM (compared to 14–24 GPM for standard flow). High flow is a separate pump or pump stage — it's not just "more pressure," it's more volume.
Attachments that typically require high flow:
High flow is typically an option at time of machine purchase (from most brands) or can sometimes be retrofitted. If you plan to run mulchers or large rotary tools, spec high flow when you buy the machine.
A piston-driven impact tool that delivers high-energy blows for breaking concrete, rock, and frozen ground. Hydraulic breakers run on standard flow auxiliary hydraulics and are sized by impact energy (joules) and blow frequency (BPM).
Sizing rule: match the breaker to your machine's weight class. Too light a breaker underperforms; too heavy stresses the carrier's lift arms and boom. Most mid-frame skid steers (6,000–8,000 lb) run breakers in the 300–600 ft-lb impact class.
See also: Hydraulic Breaker Attachments → | Shop Breakers →
The arc the loader arms follow as they raise from ground to full height. Affects how the attachment behaves through the lift cycle:
For most attachment use (grading, land clearing, grapple work), lift path doesn't change much. For pallet forks in tight warehouses or loading trucks from height, vertical lift is noticeably better.
A rotary brush cutter or mulching head designed without a front shield or deflector plate across the cutting opening. Standard brush cutters have a closed front that forces material to be processed before it can escape; open-front cutters allow stems and brush to enter the cutting area freely from the front.
Why it matters:
See also: Skid-Pro Open-Front Brush Cutter → | Brush Cutter Attachments →
The pressure at which your machine's hydraulic system operates. Almost all modern skid steers and CTLs run at 3,000–3,500 PSI — this is standardized enough that PSI is rarely a compatibility problem. When an attachment lists a PSI requirement, it's specifying the minimum pressure to operate correctly; your machine almost certainly meets it.
PSI and GPM are often confused. PSI is pressure; GPM is volume. High flow means more volume (GPM), not more pressure. The two interact (hydraulic power = PSI × GPM ÷ 1,714), but matching flow rate is what drives most compatibility decisions.
An attachment with a rotating drum fitted with steel tines or paddles that agitates and grades topsoil, breaks up clods, removes rocks and debris, and prepares seedbeds. Power rakes run on standard-flow auxiliary hydraulics.
The drum typically counterrotates against travel direction, bringing rocks and debris to the surface where they collect behind the drum or in side discharge. Most Canadian landscapers and turf contractors use power rakes for:
See also: Soil Conditioner Attachments → | Shop Power Rakes →
A system that allows the operator to connect or disconnect hydraulic attachments from inside the cab without getting out and manually connecting hose fittings. Hydraulic quick couplers use self-sealing flat-face or poppet-style couplings that join when you push the hoses together and seal when separated.
Standard practice on most Canadian worksites is to use flat-face (ISO 16028) or Pioneer-style couplers. These are industry standard and largely interchangeable.
See also: Hydraulic Couplers Guide →
The maximum load a skid steer is rated to safely carry in normal operation, as defined by SAE J818. ROC is set at 35% of tipping load — the point at which the machine begins to tip forward.
This 35% safety margin exists because skid steers are driven over uneven ground, through ruts, and sometimes at speed. A machine carrying its rated capacity at 35% of tip has meaningful reserve before the front wheels lift.
ROC is measured at the full rated lift height with the standard bucket. Attachments can change the effective capacity — a long boom attachment like a tree spade or post driver shifts the center of gravity forward, effectively reducing your safe working load compared to a bucket at the same weight.
Common confusion: ROC is not a weight limit in the sense that the machine breaks or fails above it — it's a safe operating limit. Some operators routinely push above ROC on smooth ground, but this increases tip risk and voids warranty on structural components. On Canadian job sites with frozen rutted ground or slope, respect ROC.
See also: Tipping Load | ROC Explained in Full → | Attachment Weight Guide →
Some European and older North American manufacturers used to rate machines at 50% of tipping load rather than the SAE standard of 35%. This means their published ROC is higher relative to actual tip-over risk than SAE-rated machines.
When comparing machines across manufacturers, always check whether the ROC is SAE J818 (35%) rated. Most major brands (Bobcat, Caterpillar, Case, John Deere, Kubota, New Holland) use SAE ratings. A few imported brands and older machines may still use 50%. A 50%-rated machine with an ROC of 2,000 lb is less stable at that load than an SAE-rated machine with the same number.
The SAE International standard defining how skid steer rated operating capacity (ROC) is measured and reported. J818 mandates that ROC be set at 35% of static tipping load on a level, hard surface with the machine in its standard configuration. The standard also specifies the test procedure for measuring tipping load.
All major North American manufacturers report ROC per SAE J818, making cross-brand comparisons valid. When you see "ROC: 2,690 lb (SAE J818)" in a spec sheet, you're seeing a standardized, comparable number.
The de-facto standard attachment mounting plate system used across most skid steer brands. SSQA defines the geometry of the attachment plate: two vertical receiver pockets at the top and two lower hooks that engage the machine's coupler. The standard allows any SSQA attachment to mount on any SSQA machine regardless of brand.
SSQA-compatible brands (accept standard third-party attachments without adapter plates):
Partially proprietary systems (adapter plate or spec verification required):
See also: Universal Quick Attach Compatibility Guide → | Bob-Tach vs SSQA →
The base auxiliary hydraulic circuit available on all skid steers, typically delivering 14–24 GPM depending on machine size. Standard flow is sufficient for the majority of common attachments: augers, power rakes, angle brooms, post drivers, stump grinders (most models), hydraulic breakers, and smaller snow blowers.
The term "standard flow" doesn't mean weak or inadequate — most productive attachment work is done on standard flow machines. It becomes a limitation only when you need mulchers, large rotary tools, or large snow blowers.
See also: High Flow | Standard Flow vs High Flow — Full Guide →
An attachment that removes tree stumps by grinding them below grade with a rotating carbide-tipped cutting wheel. Skid steer stump grinders run on standard-flow auxiliary hydraulics and are significantly more efficient than walk-behind units on any stump over 12" diameter.
Sizing: match the cutting wheel diameter and HP rating to your machine's auxiliary flow and the typical stump size. Hardwood stumps (oak, maple, birch) are much harder to grind than softwood (spruce, pine, poplar) — factor this into model selection for Canadian sites.
See also: Stump Grinder Attachments → | Shop Stump Grinders →
The load at which a skid steer begins to tip forward, measured on a level hard surface with the machine in its standard configuration. Tipping load is the parent number from which ROC is derived (ROC = 35% of tipping load per SAE J818).
Tipping load itself isn't a number you should be working near — it's included in spec sheets for comparison purposes. Some operators use tipping load to gauge machine stability potential, but day-to-day operation should stay within ROC.
Factors that affect effective tipping load:
A bolt-on bar with individual pointed teeth (usually forged steel or carbide-tipped) that replaces or supplements the flat cutting edge on a general-purpose bucket. Tooth bars dramatically improve bucket penetration in hard-packed gravel, clay, frozen ground, and root mats.
For Canadian spring and fall conditions — where soil can be frozen, compacted, or full of roots — a tooth bar is often the difference between a bucket that works and one that skates across the surface.
See also: Tooth Bar Guide →
A feature on snow blades and dozer blades where the bottom cutting edge is spring-loaded and designed to trip (kick back) when it strikes a fixed object — a manhole cover, expansion joint, curb, or buried obstacle — rather than transmitting that impact force to the loader arms and machine frame.
Trip edges are particularly important in Canadian snow removal for two reasons:
Trip edge blades cost more than fixed-edge alternatives but are standard on quality snow removal equipment. For commercial snow contracts on paved lots and parking structures, a trip edge is basically mandatory.
See also: Snow Blade Attachments → | Shop Snow Blades →
See SSQA — Skid Steer Quick Attach. "Universal quick attach" and "SSQA" are used interchangeably in the industry and in supplier listings. When a product says "universal quick attach compatible," it means it uses the standard SSQA plate geometry and will fit any machine running that standard (Bobcat requires a separate Bob-Tach plate).
A hydraulic-powered compaction plate that vibrates at high frequency to compact granular material — gravel, road base, sand, backfill. Far faster than a walk-behind plate compactor for trench backfill, driveway prep, and road base work.
Sizing: match plate width and compaction force to your machine and the material. Most mid-frame machines can run standard vibratory plates (typically 25–40 GPM). Large plates may require high flow.
See also: Vibratory Plate Compactor Attachments →
A drivetrain feature on skid steers and CTLs that allows the operator to select between two speed ranges: a lower-speed, high-traction range (good for digging, pushing, and heavy lifting) and a higher-speed travel range for moving across a site.
Standard skid steers typically top out at 6–7 km/h. A 2-speed machine can hit 12–14 km/h in high range — a significant productivity advantage when you're covering distance on large sites (acreage work, farms, large construction sites).
For attachment use, 2-speed is most valuable for:
2-speed is not a standard feature on all machines — it's often an option or standard on larger models. If you're buying a machine for high-travel-distance work (Canadian farm use, large acreage clearing), it's worth the upcharge.
A bucket with a hydraulically-operated clamshell lower jaw, allowing it to function as four tools in one: standard bucket (scooping), grapple/clamshell (grabbing), blade (dozing with jaw open), and a scraper/level tool. Requires double-acting auxiliary hydraulics.
Popular for farm and acreage work in Canada where versatility reduces the number of attachments needed. Less specialized than a dedicated grapple for grabbing or a dedicated bucket for scooping — but useful when you're doing mixed tasks and don't want to switch tools.
See also: Shop Buckets →
Missing a term? This glossary is updated regularly. Check back or browse the full guides section.