Is thicker trimmer line better?

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Written By Dominic Howard

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When it comes to buying a new trimmer line for your string trimmer or weed whacker, one of the key considerations is the thickness or diameter of the line. A thicker line tends to be more durable and provide better cutting power, but is it always the better choice?

In this post, we’ll take an in-depth look at trimmer line thickness to help you decide if thicker is really better.

What is Trimmer Line?

First, let’s start with a quick overview of what the trimmer line actually is. A Trimmer line, also called weed whacker line or weed wacker string, is a flexible nylon string that rotates at high speeds to cut grass and weeds. It is fed from a spool housed inside the trimmer head. As the trimmer’s motor spins the head, the line spins as well, allowing you to trim grass and weeds anywhere the string makes contact.

The Trimmer line comes in different diameters, typically ranging from .065” to .155” thick. The thicker line is able to withstand more force and resist breaking, while the thinner line is more flexible and may provide a more precise cut.

Benefits of Thicker Trimmer Line

Now that we know the basics, let’s look at why someone may want to choose a thicker trimmer line:

  • More durability: The thicker line is more resistant to abrasion, punctures, and general wear. It holds up better when trimming around rocks, fence posts, and woody brush.
  • Increased cutting power: The extra thickness gives more force to cut through thick grass and weeds. It can tackle small saplings, woody vines, and overgrown areas better than thin lines.
  • Longer line life: With its added strength, a thicker line generally lasts longer before requiring replacement. You’ll need to bump-feed new lines less often.
  • Reduced vibration: A thicker line helps absorb vibration from the trimmer head spinning at high speeds. This makes the tool more comfortable and reduces fatigue.
  • Better torque: More diameter means more surface area to rotate and maintain the motor’s torque. A thick line is less likely to slow down when met with resistance.

For powerful gas trimmers and commercial use, a thickness of .095” to .155” is common. Homeowners with electric or battery-powered trimmers typically opt for a .065” to .080” line for adequate strength without overloading the motor.

Downsides of Thick Line

Of course, a thicker trimmer line also comes with some tradeoffs:

  • Less precision: Thin line allows for more accurate edging and trimming around delicate objects. A thick line can be trickier to maneuver.
  • Requires more power: Pushing thicker lines through grass takes more force. Underpowered electric and battery trimmers may have trouble.
  • Increased weight: More mass of material rotating on the spool can increase vibration and weight at the end of the trimmer. This may lead to more user fatigue over long trimming sessions.
  • Cost: Thicker specialty lines are priced higher per foot than value packs of thin lines. Expect to pay more for heavy use.
  • Overkill for light duty: For homeowners with occasional trimming needs, the thick commercial line may be unnecessary overkill.

So when is a thick line not ideal? On underpowered trimmers, for finishing work around fences or landscaping, or for light trimming of smaller properties, a .065” to .080” line should be sufficient.

Line Thickness Recommendations

Here are some general recommendations on selecting the right line thickness for different situations:

  • Battery/electric trimmers under 15amps: .065” – .080” line
  • Electric trimmers 15amps and up: .080” – .095” line
  • Gas trimmers under 30cc: .080” – .095” line
  • Gas trimmers over 30cc: .095” – .155” line
  • Occasional homeowner use: .065” – .080” line
  • Regular suburban trimming: .080” – .095” line
  • Overgrown areas/heavy weeds: .105” – .155” line
  • Professional/commercial use: .105” – .155” line

Of course, also check the line capacity recommended for your specific trimmer model in its manual. Using a line that’s too thick for the trimmer can overload the motor.

Factors that Determine Optimal Thickness

When fine-tuning your choice of line thickness, consider these factors:

  • Motor power: Electric and battery-powered motors generate less torque than gas engines. Match the line to the trimmer motor’s output.
  • Cutting conditions: Thicker grass, weeds, and brush require more cut strength from the line.
  • Comfort: Heavier lines cause more vibration and fatigue over extended use.
  • Trimmer model: The manufacturer’s recommendations account for the gearing and power of that specific trimmer.
  • Cost: Thicker specialty lines get priced higher than value-pack thinner lines. Balance strength needs with your budget.

Getting the right gauge suited for your trimmer, property, and cutting conditions will provide the best performance and value.

Line Material Choices

In addition to diameter, trimmer lines come in different material compositions. Here are some of the most common:

  • Nylon: The standard for its balance of strength, flexibility, and cost. Available in a wide range of thicknesses.
  • Polymer blends: Nylon is blended with other polymers to increase resistance to breaking while retaining flexibility.
  • Monofilament: Single-strand nylon provides a softer cutting action. Requires less motor power than other lines.
  • Twisted line: Multiple nylon strands twisted together to increase durability but with a less flexible feel.
  • Steel-core nylon: A thin steel wire in the center adds strength but also extra weight and less flexibility.
  • Plastic-alloy blends Proprietary mixes of polymers and alloys for extra durability and life. More expensive but can last 5X longer than regular nylon.

While thicker lines excel at strength, some of these specialty materials offer added endurance without as much increased diameter. Consider both factors when choosing your line.

Installation Tips

Installing a new trimmer line isn’t difficult, but here are some tips for the best results:

  • Review your trimmer manual for line capacity and installation instructions, as techniques vary.
  • Confirm the new line diameter matches your model’s specifications.
  • Use only fresh lines. Old line left on the spool too long becomes brittle.
  • Cut the line to length using scissors, not a utility knife. This seals the ends to prevent splitting.
  • Wind both lines evenly onto the spool, side-by-side, without overlapping.
  • Leave a 6-12 inch length sticking out to feed into the eyelets. Refer to your manual for the proper amount.
  • Advance the lines until they are both fed through the trimmer head and the excess length is removed by the rotating blade.

Taking a few minutes to correctly install a fresh, quality line will allow your trimmer to run safely and effectively.

Thicker Line Safety Considerations

While a thicker trimmer line offers added cutting power, keep these safety precautions in mind:

  • The force of the heavier line spinning at high speeds can kick up more debris. Always wear protective glasses.
  • The line throws off more vibrations. Use thick anti-vibration gloves and limit extended operation to avoid hand numbness.
  • Heavier lines create more drag and resistance for the motor. Periodically rest the trimmer to avoid overheating.
  • Rotate at lower speeds for less kickback force, especially around fragile objects like fence posts or retaining walls.
  • Maintain a safe distance from people, animals, vehicles, and hazardous materials when trimming. Stop the head when crossing surfaces where the line could damage property.
  • Check lines before each use for wear, breaks, or loose fittings that could allow pieces to fly off at high speeds.

A few common sense precautions will allow you to safely take advantage of the thicker trimmer line’s power while avoiding injuries or property damage.

Frequently Asked Question

1. Why should I consider using a thicker trimmer line?

Thicker trimmer lines generally offer increased durability and cutting power, making them suitable for tougher vegetation and larger yards.

2. What is the advantage of using a thicker trimmer line over thinner options?

Thicker trimmer lines are less prone to breakage, can handle thicker grass and weeds, and provide more efficient cutting, saving you time and effort.

3. Will a thicker trimmer line fit my trimmer?

Trimmer compatibility depends on the manufacturer’s specifications. Check your trimmer’s manual or contact the manufacturer to ensure compatibility with thicker lines.

4. Can I use a thicker trimmer line on a lightweight electric trimmer?

It’s essential to use a trimmer line that your machine’s motor can handle. Thicker lines might strain lightweight trimmers. Refer to your trimmer’s manual for guidance.

5. How does the diameter of the trimmer line affect its performance?

Thicker lines have a larger cutting area and are better suited for heavy-duty tasks. They can handle denser vegetation and tougher weeds more effectively.

6. Is a thicker trimmer line suitable for all types of trimming tasks?

Thicker lines are ideal for dense grass, heavy weeds, and tougher vegetation. However, for precision trimming around delicate plants, a thinner line might be more appropriate.

7. Do thicker trimmer lines consume more fuel in gas-powered trimmers?

While thicker lines may slightly increase fuel consumption due to the added resistance, the difference is usually minimal and shouldn’t significantly impact your overall fuel usage.

8. How often do I need to replace a thicker trimmer line?

The lifespan of a trimmer line depends on usage, the type of vegetation, and the terrain. Thicker lines tend to be more durable and last longer under challenging conditions.

9. Are there any safety considerations when using a thicker trimmer line?

Thicker lines can throw debris farther, so wearing appropriate safety gear, including eye protection, closed-toe shoes, and long pants, is crucial to prevent injuries.

10. Can I switch between thicker and thinner lines on my trimmer?

Many trimmers allow you to switch between different line diameters. Just ensure your trimmer head is compatible with the line thickness you want to use.


Heavier trimmer line diameters offer many advantages like increased cutting power, durability, and longer line life. But they also come with tradeoffs like less precision, added weight, and higher cost. Consider your specific trimmer model, typical cutting conditions, and comfort needs when choosing line thickness. Specialty materials like polymers and alloys also provide extra endurance without as much increased diameter. With the right choice of line for your needs, you can keep your lawn neatly trimmed without constantly bumping new lines.

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