Which way do you wind trimmer line onto the spool?

Winding direction matters because the line has to unspool in the same direction the head spins. Nearly every spool has an arrow and often the words "wind line" moulded into the plastic — follow that arrow, and the line will feed out correctly when you bump the head against the ground.

A few checks keep the load reliable.

  • Find the arrow: the moulded arrow or "wind" text on the spool shows the correct direction.
  • Wind tightly and evenly: loose or overlapping coils cross and jam instead of feeding.
  • Respect divided spools: a dual-line head has two channels, each wound in the same marked direction.
  • Leave the tails seated: tuck each end into its retaining notch so it doesn't unravel during fitting.

If you wind against the arrow, the line binds inside the head and won't advance no matter how hard you tap it. When in doubt, note which way the old line came off before you remove it, and load the new line the same way. For the full spool-changing sequence, see the string trimmers guide; keeping the tool powered off until the cap is locked avoids any accidental start while your fingers are near the head.

What happens if you wind trimmer line the wrong way?

If you wind the line against the spool's arrow, it won't feed out when you bump the head, because it's trying to unspool against the direction the head rotates. You'll tap the head repeatedly and get nothing, or the line will bind and jam inside the housing instead of advancing.

This is one of the most common reasons a freshly restrung trimmer won't feed. The line isn't faulty and the head isn't broken — it's simply loaded backwards, so the rotation that should pull line out is instead pulling it tighter against the spool. The fix is to unwind the line completely and rewind it following the moulded arrow. Because it's such a frequent mistake, it's always the first thing to check when a trimmer stops feeding right after a reload.

How do you find the winding direction if the arrow is worn off?

If the spool's arrow has worn away, work out the direction from the head's rotation: wind the line so its cutting tips trail behind the spin, which on most trimmers means winding opposite to the way the head turns in use. Noting how the old line came off before you remove it is the simplest guide of all.

Use this sequence when there's no visible arrow:

  1. Before removing the old line, watch or feel which way it wraps and unwinds off the spool.
  2. If it's already gone, spin the head slowly by hand with the tool powered off, and note its direction of rotation.
  3. Wind the new line so its free ends trail the rotation rather than leading it.
  4. Load a short length, refit the cap, and test-feed before committing to a full wind.

When you're genuinely unsure, load the line, run the trimmer briefly, and confirm it feeds; if it won't, you've almost certainly wound it backwards and can simply reverse it.

Does winding direction differ for single- and dual-line heads?

The winding direction is the same for single- and dual-line heads — both follow the spool's arrow — but a dual-line head has two separate channels that must each be wound the same marked way. Winding one channel backwards leaves that side jammed while the other feeds normally.

On a dual-line spool, keep the two lengths in their own channels and don't let them cross the divider, or they'll tangle and stop feeding together. As a worked example, a common dual-line complaint is one side feeding and the other stuck: that's almost always one channel wound the wrong way or the two lines crossed over the divider. Rewinding both in the arrow's direction, each kept in its own groove, resolves it. For the complete spool-changing sequence, the string trimmers guide walks through loading a fresh length step by step.

Does the same rule apply to pre-wound replacement spools?

Pre-wound replacement spools take the winding direction out of your hands — the maker has already loaded the line the correct way, so you simply drop the spool into the head and feed the tails through the eyelets. That convenience is the main reason many owners buy pre-wound spools instead of bulk line.

The trade-off is cost: pre-wound spools are more expensive per load than winding your own from a bulk roll. If you do wind your own, the arrow rule still applies every time; if you buy pre-wound, you skip it entirely but pay a little more for the fresh, correctly loaded line.