Auxiliary hydraulic flow is a make-or-break factor for skid steer trencher performance. It determines how fast the chain spins, how well the teeth cut through soil, and how much you can get done in a day. If the flow doesn't match what the trencher is built for, you'll get slow digging, premature wear, or worse—damage to the attachment or machine. Here's what you need to know about matching flow to the job.
What Is Auxiliary Hydraulic Flow?
Auxiliary hydraulic flow is the volume of hydraulic fluid your skid steer sends to powered attachments through the auxiliary circuit, measured in gallons per minute (GPM) or liters per minute (L/min). Machines are generally classified as standard-flow or high-flow based on that capacity. Standard-flow units typically deliver 15 to 25 GPM, while high-flow machines push 30 GPM or more. That rating matters because it directly affects how hydraulic-driven attachments—trenchers, augers, brush cutters, mulchers—actually perform on the job.
How Flow Affects Trencher Performance
The trencher's hydraulic motor turns flow into rotational force that drives the cutting chain. More flow usually means faster chain speed, which translates to more teeth passing through the soil per minute and faster trenching in most conditions—especially in looser or moderately compacted ground. But flow has to be within the trencher's designed range. A motor built for a specific flow window runs most efficiently there. Too little flow and the chain drags; too much and you risk overspeeding the chain, cooking the motor, or wearing teeth out fast.
Standard-Flow Trenchers
Standard-flow trenchers are built for skid steers with auxiliary circuits delivering 15 to 25 GPM. They typically have smaller booms, lighter chain drives, and are a natural fit for mini skid steers and compact machines. They handle light to medium digging—residential utility work, irrigation lines, landscape drainage—without breaking a sweat. The TG-TCR910(36IN)-MP600 and TG-TCR910(36IN)-MP910 are solid examples of lighter trenchers that pair well with compact machines. For rental fleets and contractors who mostly run smaller projects, standard-flow trenchers are often the smartest choice.
High-Flow Trenchers
High-flow trenchers need auxiliary circuits delivering 30 GPM or more and are designed for larger mid-frame skid steers and compact track loaders. They come with bigger booms, heavier chain drives, and handle deeper trenching in harder or more compacted soil. The TG-TCR1220(48IN)-MP1220, with cutting depths up to 1220 mm, is a good example of a larger trencher that really benefits from high-flow hydraulics. These units deliver serious productivity on bigger utility projects, road work, and agricultural drainage. Before running one, make sure your machine's high-flow circuit is activated and properly plumbed.
Can a Low-Flow Skid Steer Operate a Trencher?
Yes. Many trenchers are designed specifically for standard-flow skid steers. The key is matching the trencher's flow requirements to your machine's auxiliary circuit. Lighter trenchers with smaller booms and lower flow demands work fine on standard-flow machines. But if you try to run a high-flow trencher on a standard-flow machine, you'll get slow chain speed, poor cutting, and frustrating productivity. The trencher will turn, but it won't hit its rated digging capacity. Always check the manufacturer's flow specs and confirm your machine delivers what's needed before you start digging.
How to Check Your Skid Steer Hydraulic Flow
The most reliable way to find your skid steer's auxiliary hydraulic flow is to check the operator manual or manufacturer spec sheet. It will list both standard-flow and high-flow ratings if the machine supports both. Your dealer can also confirm the auxiliary circuit configuration using the machine serial number. Some machines have a flow gauge or display in the cab, but that's not always standard. If you're still unsure, a hydraulic flow test using a flow meter on the auxiliary circuit—done by a qualified tech—will give you a precise number. Knowing your actual flow rating is the only way to pick a trencher that will perform as expected.
Matching Flow to Your Application
When selecting a trencher, think about both your machine's flow capacity and the work you do most often. For residential utility work, irrigation, and landscape drainage on compact machines, a standard-flow trencher with a 36 in boom is usually enough. For larger utility projects, road construction, or agricultural drainage that needs deeper trenches in harder ground, a high-flow machine with a 38 in or 48 in boom trencher will give you the productivity you need. Understanding how to choose a skid steer trencher and reviewing the skid steer trencher sizing guide will help you match both flow and dimensions to your work. The skid steer trencher product page lays out the detailed specs for each configuration.
