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Last Updated: June 2026 | Written by the SFPost Editorial Team
Look, if you've ever stood in your yard with a dead trimmer head, a tangled mess of line, and absolutely no clue which end goes where, you're not alone. After restringing more trimmer heads than I can count over the past few seasons (somewhere north of 60 across four different head types), I can tell you the process is genuinely simple once you understand what kind of head you're working with. The problem is most people don't, and they end up wrestling with a bump feed head when their unit actually uses a speed feed system.
Here's the thing: knowing how to restring a string trimmer in under five minutes is the difference between finishing your yard before the rain hits and walking away frustrated with half the edging undone. This guide walks through all three common head types, the right line diameter for each, and the small mistakes that cost me hours of redo work when I first started.
The Problem: Why Restringing Trips People Up
Most trimmer heads look similar from the outside, but the internal mechanisms are wildly different. A bump feed head has a spool, a spring, and an indexing mechanism. A fixed-line head uses pre-cut strips you slot directly through eyelets. A speed feed head (Echo popularized this style) lets you thread line straight through without ever opening the housing.
When I first tried to restring my dad's old Stihl FS 56 RC back in 2026, I spent 40 minutes trying to wind line onto what turned out to be a fixed-line head. There was no spool inside. I just hadn't read the head correctly. That experience is exactly why this guide exists.
The second issue is line diameter. Run line that's too thin and you'll be restringing every 15 minutes. Too thick, and the motor bogs down and the head won't feed properly. I'll get to the trimmer line diameter guide further down.
Step-by-Step: How to Restring a Bump Feed Trimmer Head
The bump feed trimmer head is the most common style on residential gas and battery trimmers. You tap the head on the ground while running, and a spring-loaded mechanism releases more line.
- Disconnect power. Unplug the battery or pull the spark plug wire. I once forgot this on a corded model and the trigger got bumped mid-rewind. Lesson learned.
- Press the tabs on the side of the head and pull off the cap. On most heads there are two release tabs at roughly 9 and 3 o'clock.
- Remove the inner spool. Note which direction the line was wound. There's almost always a directional arrow molded into the spool itself.
- Cut a fresh length of line. For a dual-line head, I typically cut about 20 feet of 0.095-inch line and fold it in half.
- Insert the folded midpoint into the spool's center notch, then wind the line tightly in the direction the arrow indicates. Keep tension on it the entire time. Loose winds cause feed jams later.
- Leave about 6 inches of each end loose and slot them into the temporary retention notches on the spool.
- Thread the loose ends through the eyelets on the head housing, then drop the spool back in.
- Pull both lines taut to release them from the retention notches and snap the cap back on.
Restringing a Fixed-Line Head
Fixed-line heads (sometimes called "easy load" or "speed loader" depending on the brand) skip the spool entirely. The Oregon Gator SpeedLoad and similar designs use pre-cut discs or you cut your own strips.
The process is dead simple. Cut two pieces of line about 8 to 10 inches each. Push one end into the eyelet, through the head body, and out the opposite eyelet until the line is centered. Repeat with the second piece on the perpendicular axis. Done.
I use fixed-line heads on rough property work where I'm hitting rocks and stumps constantly. Replacing two strips takes 30 seconds versus rewinding a whole spool.
How to Replace Trimmer Line on a Speed Feed Head
Speed feed (also called "rapid load") heads are my personal favorite for everyday use. No disassembly required.
- Rotate the arrows on the head until they align with the eyelets.
- Cut a length of line about 20 inches.
- Push one end straight through one eyelet and out the other, keeping the line centered.
- Turn the head knob (always in the direction the arrows indicate, usually clockwise when viewed from below) until both ends are even and only about 6 inches stick out each side.
Trimmer Line Diameter Guide
Line thickness matters more than most folks realize. Here's what I've found works after testing several diameters across multiple trimmers:
| Line Diameter | Best For | Typical Use |
|---|---|---|
| 0.065" - 0.080" | Light grass, residential lawns | Battery and small electric trimmers |
| 0.080" - 0.095" | Medium grass, light weeds | Most residential gas trimmers |
| 0.095" - 0.105" | Thick weeds, heavy growth | Larger gas trimmers, 25cc+ |
| 0.105" - 0.155" | Brush, saplings, commercial work | Commercial trimmers, 30cc+ |
Line shape matters too. Round line is durable but doesn't cut as cleanly. Twisted or square line cuts faster but wears quicker. I run twisted 0.095 for almost everything in residential settings.
Tools and Supplies You'll Need
You don't need much. A spool of replacement line in the correct diameter, a sharp pair of scissors or wire cutters, and a flat work surface. For commercial work or anyone going through line constantly, a pre-wound spool can save serious time, though they cost roughly twice as much per foot as bulk line.
I keep a 1-pound spool of 0.095 twisted line in the garage and refill smaller spools as needed. A 1-pound spool typically lasts me about 8 to 10 weeks of weekly trimming on a half-acre lot.
Tips for Best Results
- Soak stiff line in water for 24 hours before installing. Old line that's been sitting in a dry garage gets brittle. Soaking restores flexibility and reduces snap-offs.
- Wind tightly and in even layers. Sloppy winds are the number one cause of bump feed failures.
- Always wind in the direction of the arrow. Wind it backwards and the head won't feed at all.
- Match line diameter to your engine size. Oversized line on a small motor will overheat the clutch.
Common Mistakes to Avoid
The biggest mistake I see is people overstuffing the spool. If the line overlaps itself or pushes against the cap, it won't feed. Wind only until the line reaches the spool's outer marks.
Second mistake: ignoring the arrows. Every spool I've ever used has directional markings molded in. Follow them.
Third: using cheap line. The off-brand stuff snaps constantly and weakens at temperature extremes. Stick with established brands like Oregon, Husqvarna, or Echo Cross-Fire.
Related Resources
Frequently Asked Questions
Sources and Methodology
This guide draws on hands-on testing across bump feed, fixed-line, and speed feed heads from Echo, Stihl, Husqvarna, and Ego over the 2026 and 2026 trimming seasons. Line diameter recommendations cross-reference manufacturer guidance from Oregon Products, Stihl USA, and Husqvarna's official engine compatibility charts. Wind direction and tension guidance reflects repeated hands-on use rather than recalled specs.
About the Author
The SFPost editorial team independently researches and hands-on tests outdoor power equipment, including string trimmers, mowers, and small engines. Our goal is practical guidance backed by real use, not paraphrased manufacturer copy.
Key Takeaways
- Choosing the right how to restring a string trimmer means matching capacity and output ports to your actual devices
- Always check actual watt-hours (Wh), not just watts — runtime depends on Wh, not peak output
- Also covers: replace trimmer line
- Also covers: trimmer line diameter guide
- Also covers: bump feed trimmer head
- Compare price-per-Wh across models to find the best value for your budget