How Long Can a 27-Ton Excavator's Long Reach Arm Be? How Much Counterweight Is Needed?

In special working conditions such as earthmoving, river dredging, and high-reach demolition, standard excavator arms often fall short of the required reach. In such cases, long reach arms become an essential modification. For 27-ton excavators, installing a long reach arm is a common customization. However, one key question often arises: **How long can a 27-ton excavator's long reach arm be, and how much counterweight is needed to ensure safety and stability?**

This article draws from real-world use cases and mechanical engineering principles to answer that question in detail, offering a professional reference for anyone considering purchasing or modifying a long reach arm.

A 27-ton excavator falls into the mid-to-large category. Its standard arm (boom + stick) typically ranges from 9 to 10 meters, with a working radius of around 9–10 meters. By replacing it with a long reach arm, the working radius and depth can be significantly increased to meet special job site needs.

Generally, the structural strength and chassis load capacity of a 27-ton excavator make it suitable for long reach arms between **18 and 24 meters**. While longer arms such as 26 or even 28 meters can be fabricated, they pose serious challenges to machine stability and operational efficiency and are not recommended for typical construction jobs.

While long reach arms improve performance, they also significantly increase the forward tipping moment. To maintain machine balance and ensure safe operation, **additional counterweight** is often required to redistribute the center of gravity.

Below are recommended counterweight guidelines for a 27-ton excavator fitted with various long reach arms and bucket sizes (0.45 m³ or 0.6 m³):

Bucket Size: 0.45 m³
Additional Counterweight: Not required
Notes: This length is within the optimal range for a 27-ton excavator. The original factory counterweight is sufficient, and no extra load is necessary.
If using a 0.6 m³ bucket: Add 500 kg of counterweight to offset the extra tipping force caused by the larger bucket volume.

Bucket Size: 0.45 m³
Additional Counterweight: 2 tons required
Notes: The longer reach significantly increases leverage. Without additional weight, the excavator may experience front-tilting or light tail-end instability, especially on soft ground or during high-angle operation.

Bucket Size: 0.45 m³
Additional Counterweight: 3.5 tons required
Notes: This is near the upper operational limit for a 27-ton excavator. Machine stability now heavily depends on counterbalance. It's recommended to use custom-welded steel counterweights that are firmly secured to the tail to avoid shifting during operation.

Bucket Size: 0.45 m³
Additional Counterweight: 5 tons required
Notes: At this length, the excavator has a very high tipping risk without proper counterweight. In addition to weight, users should inspect the undercarriage and track systems to ensure structural integrity under the increased load.

There are several ways to add counterweight:

1. Bolt-On Steel Counterweight Blocks: The most common method. Steel blocks are mounted on the rear based on the required weight.
2. Rear Counterweight Box: A welded metal box is installed at the back, filled with sand, iron pellets, or concrete for adjustable weight.
3. Chassis Reinforcement: Some users choose to extend or widen the undercarriage to increase base stability, reducing the need for heavy counterweights.

Important Notes: 

Counterweights must be securely attached to the excavator’s rear frame to prevent detachment or shifting.
Do not blindly add weight—overloading the machine can damage the undercarriage, travel motors, and swing bearings.
The counterweight must match the arm length and bucket capacity. We strongly recommend consulting a professional supplier for accurate calculations rather than relying on guesswork.

One client used a 27-ton excavator with a 22-meter long reach arm and a 0.45 m³ dredging bucket for river cleaning. Initially, no counterweight was added. During operation, the rear end felt light, and the front tracks tended to lift slightly. After consulting technical experts, they added a 3.5-ton counterweight, which significantly improved machine stability and efficiency. This case illustrates that even with a smaller bucket, proper counterweight is essential for safe and efficient operation.

For users of 27-ton excavators, upgrading to a long reach arm can greatly expand the range of operations. However, it’s critical to **match the arm length with the appropriate counterweight** to ensure safety and reliability.

Recommended:

Long Reach Arm Length	Bucket Size	Counterweight Needed	Remarks
18 meters	0.45 m3	None	Stable operation
18 meters	0.6 m3	500 kg	Slight adjustment needed
20 meters	0.45 m3	2 tons	Moderate risk, balance required
22 meters	0.45 m3	3.5 tons	Structural reinforcement recommended
24 meters	0.45 m3	5 tons	High tipping risk, caution required

When choosing a long reach solution, we recommend that customers evaluate their specific working environment, required digging radius, and bucket capacity. Always work with a professional long reach arm manufacturer who can calculate the counterweight scientifically and customize the solution to your machine model.

If you're considering upgrading your 27-ton excavator with a long reach arm or need precise counterweight advice, feel free to contact us. With years of experience in custom long reach solutions, we can provide you with safe, efficient, and professional support from design to delivery.
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