What Actually Determines an Excavator’s Digging Force?

When comparing excavators, one of the first specs people look at is digging force. It’s often listed in bold numbers—bucket breakout force, arm digging force—and used as a shorthand for how “strong” a machine really is. But those numbers don’t tell the whole story. An excavator’s true digging power is the result of several systems working together, not just a single hydraulic rating.

So what actually determines how hard an excavator can dig? Let’s break it down.

Hydraulic System Pressure and Flow

At the heart of digging force is the hydraulic system. Excavators rely on hydraulic pressure to convert engine power into movement and force. Higher system pressure allows the cylinders to exert more force, but pressure alone isn’t enough.

Hydraulic flow matters just as much. A system with high pressure but limited flow may produce strong breakout force but feel slow and unresponsive. Modern excavators balance pressure and flow to deliver both power and smooth, controllable movement. Advanced hydraulic systems also adjust flow dynamically, directing power where it’s needed most during digging.

Cylinder Size and Geometry

The physical size of the hydraulic cylinders plays a major role. Larger diameter cylinders generate more force at the same pressure, which is why heavier machines typically have greater digging force.

Just as important is cylinder placement and linkage geometry. The angles at which cylinders push on the boom, stick, and bucket determine mechanical advantage. Some excavators are designed to maximize breakout force at the bucket curl, while others prioritize consistent force throughout the digging arc. This is why two machines with similar specs can feel very different in the trench.

Boom, Stick, and Linkage Design

Not all excavator arms are created equal. The length and shape of the boom and stick affect leverage. Shorter arms usually provide more force but less reach, while longer arms increase reach at the expense of raw digging power.

Linkage design also influences how efficiently force is transferred to the bucket. Z-bar and other linkage styles can dramatically improve breakout force, especially when prying compacted material or rock.

Machine Weight and Stability

Digging force isn’t just about how hard the hydraulics push—it’s also about how much force the machine can apply without lifting itself off the ground. Heavier excavators can transfer more power into the ground because their weight provides stability and counterbalance.

Undercarriage width, track length, and counterweight size all affect how much usable digging force the operator can apply before the machine becomes unstable.

Bucket Size, Shape, and Teeth

The bucket is where digging force meets the ground. A wider bucket spreads force over a larger area, reducing penetration. A narrower bucket concentrates force, making it easier to break through dense material.

Tooth style matters too. Sharp, aggressive teeth cut into hard ground far more effectively than worn or blunt ones. In many cases, upgrading bucket teeth can make a noticeable difference in real-world digging performance without changing the machine itself.

Operator Technique

Even with identical machines, digging force can vary depending on who’s in the seat. Skilled operators know how to position the machine, use curl and stick force together, and maintain optimal angles to maximize breakout force.

Poor technique can waste hydraulic power and make a strong excavator feel weak, while good technique can make a mid-sized machine outperform expectations.

Published Specs vs Real-World Performance

Manufacturers typically publish two key numbers: bucket breakout force and arm digging force. These are measured under specific conditions, usually at optimal angles and with standardized setups. In the real world, digging conditions vary, and those peak numbers may only be achievable briefly.

That’s why real-world performance depends on how all these factors work together, not just what’s printed on a spec sheet.

The Bottom Line

An excavator’s digging force isn’t determined by one number or component. It’s the result of hydraulic pressure and flow, cylinder size and geometry, machine weight, linkage design, bucket setup, and operator skill all working in harmony.

Understanding these factors helps you look beyond the spec sheet and choose a machine that actually performs the way you need it to on the job site—where it really counts.