How to Match the Length of a Long Arm Based on Excavator Tonnage?

May 30, 2026

Upgrading to an excavator long arm is a game-changer for specialized construction projects. However, simply buying the longest arm available isn't the smartest choice. The golden rule of heavy equipment modification is strict: the length of the long arm must perfectly match the tonnage of the base excavator. Failing to balance the machine's weight and leverage can lead to severe instability, hydraulic failures, or even catastrophic tipping accidents.

Here is a practical guide to matching excavator tonnage with the optimal long arm length:

Lightweight Excavators (10 - 16 Tons)
For smaller machines, extending the reach too far will compromise their lifting capacity and stability. Therefore, a 10 to 16-ton excavator should generally be matched with a long arm no longer than 13 meters. Pairing this with a proportionally smaller bucket ensures smooth operation during light-duty trenching or landscaping tasks.

Medium-Duty Excavators (20 - 25 Tons)
This is the sweet spot for many municipal and infrastructure projects. A 20 to 25-ton excavator provides enough counterweight and hydraulic power to support a 15.4-meter to 18-meter long arm. This combination is ideal for medium-depth foundation pits and urban river cleaning, offering an excellent balance between reach and digging force.

Heavy-Duty Excavators (36 - 40 Tons)
When tackling large-scale earthmoving or deep harbor construction, heavy-duty machines are required. A 36 to 40-ton excavator can safely accommodate a 22-meter long arm. At this scale, manufacturers often reinforce the boom structure and adjust the hydraulic system to handle the increased stress and leverage.

Super-Heavy Excavators (45 - 65 Tons)
For mega-projects requiring maximum reach, super-heavy excavators are the ultimate choice. Machines weighing between 45 and 65 tons can be equipped with long arms reaching up to 26 meters. To maintain the center of gravity at this extreme extension, these setups require significant additional counterweights—sometimes exceeding 5 tons—to prevent the rear of the machine from lifting off the ground during full-reach operations.

Always remember: Tonnage dictates reach. Proper matching ensures that your excavator operates safely, efficiently, and with a prolonged service life. Before purchasing, always consult with professional engineers to conduct a thorough stress analysis and ensure your hydraulic system is fully prepared for the upgrade.