What Size String Does Ryobi Weed Eater Take? Chart

Introduction

Ryobi is one of the most trusted names in DIY and homeowner lawn care equipment, with a full lineup of gas, cordless, and corded weed eaters built to tackle everything from neat lawn edging to overgrown brush. If you own a Ryobi weed eater, you’ve likely asked yourself: What Size String Does Ryobi Weed Eater Take? Using the incorrect trimmer line diameter is one of the most common causes of poor performance, premature tool wear, and even permanent motor damage. The right string size ensures your weed eater cuts efficiently, runs smoothly, and lasts for years of reliable use. This comprehensive guide covers the exact string sizes for every current and recent Ryobi weed eater model, includes an easy-to-reference size chart, walks through how to measure your existing string, provides a step-by-step replacement guide, and shares expert tips to avoid common mistakes. Whether you’re a first-time weed eater owner or a seasoned lawn care pro, this guide has all the information you need to keep your Ryobi tool running at its best.

• Why Correct Ryobi Weed Eater String Size Matters
• Ryobi Weed Eater String Size Chart
• Step-by-Step Guide to Replacing Ryobi Weed Eater String
• Tips for Optimal Ryobi Weed Eater Performance
• Common Mistakes to Avoid When Choosing String Size
• Frequently Asked Questions
• Conclusion

Why Correct Ryobi Weed Eater String Size Matters

It’s easy to assume all trimmer string is the same, but the diameter of your line has a direct impact on every part of your weed eater’s performance and longevity. Using a string that is too thick forces the motor to work harder to spin the heavier line, leading to increased heat buildup, reduced fuel efficiency for gas models, shorter battery life for cordless models, and accelerated wear on internal components like the gearbox and spindle. Over time, this excess strain can cause the motor to burn out entirely, leading to costly repairs or the need to replace the tool entirely. For gas models, incorrect string size can also lead to increased exhaust emissions and fouled spark plugs, adding to maintenance costs.

On the other hand, using string that is too thin leads to constant breakage, especially when cutting thick weeds, woody stems, or dense vegetation. Thin line also lacks the mass to cut cleanly, leaving uneven, frayed edges on grass and failing to tackle tougher plants. This leads to wasted time, frequent string replacements, and frustration during lawn care tasks. In some cases, using unapproved string sizes can even void your Ryobi tool’s manufacturer warranty, as damage from incorrect parts is not covered under standard warranty terms. Sticking to the recommended string size for your specific model is the simplest way to avoid these issues and get the most out of your investment.

Ryobi Weed Eater String Size Chart

Ryobi groups their weed eaters into three main categories, each with standard string size ranges tailored to their power output and intended use. The chart below outlines the most common 2022–2024 Ryobi models and their recommended string diameters, so you can quickly find the right size for your tool. If you have an older model, the size ranges below still apply for most standard Ryobi weed eaters.

Gas-Powered Ryobi Models

Ryobi’s gas-powered weed eaters are built for heavy-duty use, including large yards, overgrown areas, and thick brush. The vast majority of these models use 0.080-inch (2.0 mm) diameter trimmer line, which balances cutting power and durability for demanding tasks. Higher-displacement 30cc and larger gas models, such as the RY4CS 4-cycle weed eater, can also accommodate 0.095-inch (2.4 mm) string for extra cutting power when tackling very dense vegetation. Most gas-powered Ryobi models use a bump-feed system, where you tap the bottom of the trimmer head on the ground to release more line as it wears down.

Cordless Electric Ryobi Models

Ryobi’s cordless weed eaters run on their 18V, 40V, and 80V ONE+ battery platforms, with string sizes varying by power output. Compact 18V models designed for light trimming and edging in small yards use 0.065-inch (1.65 mm) diameter string, which is lightweight and easy for the lower-power motor to spin. Higher-voltage 40V and 80V models built for large yards and all-day use use 0.080-inch (2.0 mm) string for improved cutting power and durability. Many 18V models also support a dual-line system, which uses two strands of 0.065-inch string to double the cutting width without increasing motor strain.

Corded Electric Ryobi Models

Plug-in corded Ryobi weed eaters are ideal for smaller to medium-sized yards with consistent access to power outlets. Most standard corded models use 0.065-inch (1.65 mm) string, which is sufficient for cutting grass and light weeds. Heavy-duty corded models designed for medium-duty use can accommodate 0.080-inch (2.0 mm) string for tougher vegetation. All corded Ryobi models feature either automatic or bump-feed string advancement, depending on the specific model.

If you’re still unsure of the exact string size for your model, you can easily measure your existing string to confirm. For the most accurate measurement, use a digital caliper, which can measure to the thousandth of an inch. If you don’t own a caliper, a standard ruler can work for a close estimate: a US quarter is approximately 0.069 inches thick, so if your string is slightly thinner than a quarter, it is almost certainly 0.065-inch line; if it is slightly thicker, it is 0.080-inch line. You can also take a piece of your old string to a local hardware store, and an associate can help you match it to the correct size. Additionally, you can find the required string size by checking your model’s user manual, looking for a stamped label on the bottom of the trimmer head, or searching your model number on Ryobi’s official website support pages. For specialty models like curved-shaft trimmers or brush cutter attachments, the required string size may differ, so always confirm with the manual before purchasing replacement line.

Step-by-Step Guide to Replacing Ryobi Weed Eater String

Replacing the string on your Ryobi weed eater is a simple process that takes 10–15 minutes with basic tools. Follow these steps to replace your line safely and correctly, ensuring proper feeding and performance.

1. Disconnect all power sources first. For gas-powered models, turn off the fuel valve and disconnect the spark plug wire to prevent accidental startup. For cordless models, remove the battery from the tool. For corded models, unplug the trimmer from the electrical outlet. This is a critical safety step that prevents injury from the trimmer head spinning unexpectedly.
2. Remove the trimmer head. Locate the retaining nut, bolt, or quick-release button on the bottom of the trimmer head. For most models, turn the retaining nut counterclockwise to loosen it, then slide the old spool off the driveshaft. For quick-load models, press the release button and pull the spool straight off the shaft.
3. Remove the old string. Unwind any remaining string from the spool, and dispose of it properly. Take this opportunity to wipe out the inside of the trimmer head with a dry cloth to remove any built-up grass, debris, or dirt that could cause jams with the new string.
4. Wind the new string. Cut a length of new trimmer line equal to the length recommended for your model (most Ryobi trimmers require 10–15 feet of line). Insert one end of the line into the small anchor hole on the spool, then wind the line tightly around the spool in the direction indicated by the arrow printed on the spool (almost always clockwise). Leave 6–8 inches of line hanging out to feed through the eyelets on the trimmer head cover. If your model uses dual-line, repeat this process with a second strand of line on the opposite side of the spool, making sure the two strands do not cross during winding.
5. Reassemble the trimmer head. Slide the loaded spool back onto the driveshaft, making sure the loose ends of the string align with the eyelets on the trimmer head cover. For bump-feed models, pull the loose ends through the eyelets and out the bottom of the head. Tighten the retaining nut or secure the quick-release button, being careful not to over-tighten, which can crack the plastic trimmer head.
6. Test the trimmer before use. Reconnect the power source (spark plug, battery, or cord), and turn on the weed eater. Let it run for 10–15 seconds to make sure the string feeds properly. For bump-feed models, tap the bottom of the head on the ground to test that the line advances correctly. Trim a small patch of grass to confirm the line cuts evenly and does not wobble or break. If the string does not feed properly, turn off the trimmer and double-check that you wound the line in the correct direction and aligned the ends with the eyelets.

Tips for Optimal Ryobi Weed Eater Performance

Using the right string size is just one part of keeping your Ryobi weed eater running smoothly. Follow these expert tips to extend the life of your tool and get the best cutting results every time you use it.

• Use high-quality trimmer line. Cheap, low-quality string is made of soft, brittle plastic that breaks easily, even when used at the correct size. Ryobi OEM trimmer line is formulated to match the durability and performance requirements of their tools, but premium third-party brands like Oregon, ECHO, and Stens also make high-quality line that works well. High-quality aftermarket line is often more affordable than OEM options and performs just as well, but avoid no-name generic string, as it often wears out quickly and can damage your trimmer head.
• Wind the string tightly on the spool. Loose winding causes the line to tangle and jam inside the trimmer head, leading to poor feeding and frequent breakage. Wind the line as tightly as possible, and avoid crossing strands if you’re using a dual-line system.
• Adjust string length for your task. For edging and trimming tight spaces around sidewalks, garden beds, and fences, use a shorter string length (6–8 inches) to improve control and reduce drag. For cutting large areas of thick grass and weeds, use the full recommended length (10–12 inches) to cover more area with each pass.
• Store extra string properly. Trimmer line becomes brittle when exposed to UV light, extreme heat, or freezing temperatures. Store unused string in a cool, dark, dry place, like a garage cabinet or storage bin, to keep it flexible and durable for longer. In cold weather (below 40°F), consider using a slightly thicker string if you regularly trim in low temperatures, as cold makes standard line more prone to breakage.
• Clean the trimmer head regularly. Grass, dirt, and debris build up inside the trimmer head over time, causing jams and poor string feeding. Wipe out the head with a dry cloth every time you replace the string, and use a small brush to remove any stuck debris from the spool and eyelets.
• Use shaped line for thick vegetation. If you regularly cut thick weeds, brush, or woody stems, switch from round line to square or star-shaped line of the same diameter. Shaped line has sharp edges that cut more efficiently, and is less likely to wrap around vegetation or break under strain.

Common Mistakes to Avoid When Choosing String Size

Even experienced weed eater owners make mistakes when selecting and installing trimmer string. Avoid these common issues to keep your tool running smoothly and avoid costly repairs.

• Using a thicker string than recommended. It’s a common misconception that thicker string cuts better, but using a line that is too large for your model puts excessive strain on the motor and gearbox. This leads to overheating, reduced performance, and permanent damage to internal components. If you need more cutting power, use shaped line of the correct diameter instead of a thicker size.
• Using a thinner string than recommended. While thin string is less likely to damage the motor, it breaks constantly when cutting anything thicker than grass, leading to wasted time and frequent replacements. It also fails to cut cleanly, leaving uneven edges on your lawn.
• Winding the string in the wrong direction. Almost all Ryobi trimmer spools have an arrow printed on them indicating the correct winding direction (usually clockwise). Winding the string backwards will prevent it from feeding properly, leading to jams, breakage, and the need to rewind the spool entirely.
• Over-tightening the retaining nut. It’s tempting to crank the retaining nut as tight as possible to keep the spool from moving, but over-tightening can crack the plastic trimmer head or strip the threads on the driveshaft. Tighten the nut until it is snug, but do not use force to tighten it further.
• Skipping the test run after replacement. Many owners install new string and immediately start cutting without testing the feed first. If the string is wound incorrectly or misaligned, this can lead to jams, breakage, or even damage to the trimmer head. Always do a 10-second test run before starting your lawn care task.
• Using non-trimmer line materials. Never use rope, wire, or other non-trimmer line materials in place of purpose-made trimmer line. These materials are too heavy, too sharp, or too weak for the trimmer, and can cause serious damage to the tool or injury if they break loose while spinning at high speeds.

Frequently Asked Questions

Can I use a larger string size on my Ryobi weed eater?

No, you should never use a larger string diameter than the manufacturer recommends for your specific model. Even if the thicker line fits into the trimmer head, it places excessive strain on the motor and gearbox, leading to overheating, reduced performance, and permanent damage that is not covered under warranty. If you need to cut thicker vegetation, use a shaped (square or star) trimmer line of the same recommended diameter, or upgrade to a heavier-duty Ryobi model designed for larger line sizes.

Can I use a smaller string size on my Ryobi weed eater?

Using a smaller string size is unlikely to cause motor damage, but it will result in poor cutting performance, constant breakage, and frequent need to replace the line. Thin string lacks the mass to cut through thick weeds effectively, leaving uneven edges and making your lawn care tasks take much longer. It is not recommended, as it will cause more frustration than it is worth. Always use the exact recommended diameter for your model for the best results.

How often should I replace my Ryobi weed eater string?

There is no fixed replacement timeline, as it depends on how often you use your trimmer and what types of vegetation you cut. For light use (trimming grass around sidewalks and garden beds once a week), you will likely only need to replace the string every 2–3 months. For heavy use (cutting thick weeds, overgrown areas, and brush weekly), you may need to replace the string every 2–4 weeks. You’ll know it’s time to replace the line when it is frayed, broken, or worn down to less than 3 inches in length, or when you notice frequent breakage during use.

What type of trimmer line is best for Ryobi weed eaters?

The best type of trimmer line depends on your regular use case. For light grass trimming and edging, round 0.065 or 0.080 inch line works well and is affordable. For thick weeds, brush, and overgrown areas, square or star-shaped line of the same diameter cuts more efficiently, is less likely to wrap around vegetation, and lasts longer. Ryobi OEM trimmer line is formulated to work perfectly with their tools, but high-quality third-party options from brands like Oregon, ECHO, and Stens are also reliable and cost-effective. Avoid cheap no-name line, as it is often made of inferior materials that break easily and can damage your trimmer head.

Conclusion

Knowing the answer to What Size String Does Ryobi Weed Eater Take? is the key to getting the best performance and longest lifespan from your tool. As this guide shows, the correct string size depends on your model type: most 18V cordless and standard corded Ryobi weed eaters use 0.065-inch (1.65 mm) string, while gas-powered and high-voltage 40V/80V cordless models use 0.080-inch (2.0 mm) string, with some heavy-duty gas models supporting 0.095-inch (2.4 mm) line for the toughest vegetation. Use the chart included in this guide to quickly find the right size for your model, or measure your existing string if you’re unsure of your model number.

By following the step-by-step replacement guide, avoiding common mistakes, and using high-quality trimmer line, you’ll keep your Ryobi weed eater running smoothly for years of reliable lawn care. Whether you’re trimming neat edges around your sidewalk or clearing overgrown brush in your backyard, the right string size makes every job faster, easier, and more efficient. If you have any other questions about maintaining your Ryobi lawn care tools, check Ryobi’s official support resources or consult your tool’s user manual for model-specific guidance.