It can seem impossible to keep your string trimmer lines from breaking. No matter what you do, the lines snap or shred during routine yard maintenance. While frustrating, broken trimmer lines don’t have to be inevitable. Often, the problem comes down to using the wrong size line for your needs.
Understanding how to choose the right gauge trimmer line can prevent premature breakage. With so many sizes available though, it’s easy to pick the wrong option. From diameter to shape and material, many factors impact performance and durability.
This guide will help you select optimal trimmer lines for your equipment and landscaping tasks. Follow our tips to stop constantly replacing broken lines. Achieve smooth, uninterrupted trimming without unexpected failures.
Why Your Trimmer Line Keeps Breaking
Frequent breakage typically signals your trimmer line size isn’t right for the job. Here are common reasons lines snap before they should:
Using the Wrong Size Line
Trimmer lines come in different diameters, measured in fractions of an inch. Thicker lines can handle more rugged trimming while thinner ones suit lighter tasks. If the gauge doesn’t align with your needs, premature breakage results.
Lines that are too thin lack the strength for dense or woody vegetation. They shred quickly when contacting thicker stems and branches. On the other hand, oversized lines strain the trimmer motor. Excessive thickness makes cutting difficult and forces the equipment to work too hard.
Not Matching the Line to Your Trimmer
You have to balance line size with your trimmer’s power output. Measure the equipment’s engine displacement in cubic centimeters (cc). Higher cc values indicate more cutting power. Make sure your line thickness pairs well with available power.
If the line is too thin, the motor can’t spin it fast enough for clean cuts. But an oversized line demands more torque than the engine provides. Either mismatch places excessive stress on the equipment and trimmer line.
Hitting Solid Objects
Trimmer lines aren’t meant for prolonged contact with solid materials. Striking rocks, fence posts, curbs, and other unyielding objects can damage lines. The sudden impact forces and friction quickly degrade the material.
Pay attention to your trimming path to avoid debris and obstacles. Consider rubber deflectors that protect the line if inadvertent collisions are likely.
Choosing the Right Line Size
Selecting the optimal trimmer line thickness involves assessing your equipment and needs. Follow this process for sizing:
Measure Your Current Line
Check the diameter of the line currently installed to see what gauge your trimmer is designed for. The measurement may be printed directly on the line. If not, use calipers to determine the width and convert to a fractional inch.
Many trimmers work best with the manufacturer’s recommended size. If your old line performed well, replacing it with the same thickness is a safe bet.
Consider Your Trimmer’s Power
Next, match the line size to your equipment’s capabilities. Find the engine displacement on the trimmer chassis or in the owner’s manual. Here are some typical pairings:
- 20 – 30 cc engine: .065 – .080 inch line
- 30 – 45 cc engine: .085 – .105 inch line
- 45+ cc engine: .110 – .155 inch line
These alignments provide a balance of cutting ability and resistance to breakage. You may size up or down slightly depending on your needs.
Factor in Trimming Tasks
Your vegetation type and trimming tasks also dictate ideal line thickness:
- Grass, light weeds: .065 – .095 inches
- Heavy weeds, light brush: .105 – .115 inches
- Thick brush, woody stems: .155+ inches
Thinner lines readily slice through grass and fragile weeds. Heavy vegetation and woody stems require extra cutting power. Choose a thickness that handles your trimming challenges.
Also consider special circumstances like wet conditions that demand more thickness to power through thick vegetation. Take into account risks like nearby delicate plants that warrant thinner, more flexible lines.
Get Recommendations
Leverage other resources to dial in sizing. Check your owner’s manual for manufacturer recommendations based on the engine and intended trimming tasks.
Retailers can provide guidance to match your specific trimmer model. Pro landscapers may have insight into ideal thicknesses for local vegetation and terrain.
Shopping for the Right Size
Once you settle on the optimal diameter, it’s time to shop for replacement trimmer line. Keep these aspects in mind while browsing:
Line Diameter Markings
The fractional size should be prominently noted on trimmer line packaging. Common diameters include:
- .065 inches
- .080 inches
- .095 inches
- .105 inches
- .155 inches
Some brands may use measurements in mm instead. Double check conversions to inches before purchasing.
Material Composition
Nylon is the most common trimmer line material. It provides a good balance of strength, durability, and flexibility. Other options include:
- Monofilament nylon – Mostbasic and affordable option
- Advanced nylons – Optimized nylon blends for extra rigidity and abrasion resistance
- Polymer blends – Nylon mixed with polymers for added durability
- Composite materials – Nylon, polymers, minerals, and metals combined for maximum strength
Weigh material properties against higher cost. Basic nylon works for most homeowners, while commercial use may justify upgraded materials.
Buying Options
Trimmer line is sold:
- On spools for installation in bump head systems
- In pre-cut lengths with attached ends for easy loading
- In cartridges that feed fresh line when needed
Consider your usage level and trimmer type to pick the right quantity and format. Infrequent trimmers may opt for smaller pre-cut sets, while heavy-duty consumer units benefit from bulk spools or cartridges.
Changing Line Size Over Time
Treat your initial line size choice as a starting point. You may need to adjust thickness over time as conditions and needs evolve.
Evaluating Performance
Pay attention to how new lines handle trimming tasks. If breakage remains frequent, the material may still be too thin. Size up for enhanced durability.
However, if the trimmer bogs down and struggles to spin the line, that signals it’s too thick. The motor lacks enough power for the diameter. In that case, try sizing down.
Troubleshooting Issues
If performance problems arise, address other potential causes first before assuming it’s a sizing issue. For example:
- Clear line jams
- Replace worn trimmer heads
- Clean filters and vents
- Check drive belt tension and condition
Ruling out these common problems ensures your line thickness assessment is accurate.
Knowing When to Size Up/Down
Here are signs it may be time to switch diameters:
- Move up when:
- Frequently replacing thin, broken lines
- Upgrading to trim thicker vegetation
- Current size bogs down the motor
- Move down when:
- Oversized lines overload the motor
- Reducing damage to delicate plants
- Current size leaves uncut strands behind
Adjust in small increments, testing until you find the ideal thickness for performance and durability.
Choosing the right trimmer line size prevents frustrating mid-job breakage while optimizing cutting efficiency. Consider these tips for selecting diameter:
- Match line thickness to your trimmer motor’s power
- Use thinner lines for grass and delicate vegetation
- Thicker lines handle dense brush and woody stems
- Balance durability with trimmer performance
- Check manufacturer recommendations
- Adjust size over time as conditions dictate
With the proper gauge trimmer line, you can stop wasting time and money on replacements. Achieve smooth, uninterrupted trimming sessions and a pristine yard without unexpected failures.
The size of the trimmer line may also depend on environmental factors such as the moisture level of the grass or weeds being cut. In wet or damp conditions, thicker lines may be more effective as they can better cut through and prevent clogging.
The type of grass being cut can also determine the size of the trimmer line needed. For example, Bermuda grass, which is thick and dense, may require thicker lines compared to Zoysia grass, which is finer and less dense.
The size of the trimmer line may also vary based on the model of the string trimmer being used. Some models may be designed to work best with specific line diameters, so it’s essential to check the manufacturer’s recommendations.
The angle at which the trimmer line is being used can also affect its effectiveness. When cutting at a shallow angle, thinner lines may be more appropriate as they can better navigate around obstacles and avoid damaging nearby plants. For deeper cuts, thicker lines may be necessary.
The shape of the trimmer line can impact performance as well. Twisted or multi-sided lines may offer increased cutting ability compared to standard round lines. The tradeoff is that non-round lines can create more vibration and noise.
