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Bump Feed or Fast-Load? Choosing the Right Trimmer Head

Universal fast-load M10x1.25 left-hand thread trimmer head from Pentales Ltd

The trimmer head is the business end of a brush cutter, and the right one saves real time over a season. The wrong one wastes line, jams in thick grass, or simply will not fit your gearbox shaft. There are three main types, and each suits a different kind of work. This guide explains the differences, how to check fitment, and which head to pick for the jobs common in Mauritius.

The Three Main Types

Bump feed heads carry a wound spool inside; tap the head on the ground while running and centrifugal force feeds out fresh line. They hold plenty of line and suit long sessions in varied grass — the AutoCut-style heads in this family are the workhorses on most Stihl-pattern machines. Fast-load heads skip the winding: you cut a length of line, push it straight through the head, and twist to lock. Reloading takes seconds without opening anything, which matters when line breaks often in rough going. Fixed-line heads take pre-cut strips and are toughest of all, best for heavy scrub where line breaks constantly.

Fitment: the Thread Decides

Before anything else, check your gearbox shaft. Most straight-shaft brush cutters use an M10 x 1.25 mm left-hand thread — the head loosens clockwise, opposite to a normal nut. Curved-shaft and some domestic machines use different threads, and Stihl-pattern heads often need a matching shoulder nut. Measure the shaft or check your machine's manual; universal heads in the M10 x 1.25 left-hand pattern fit the great majority of machines sold in Mauritius.

Line Diameter and Shape

Match the line to the head and the job. Light grass and edging: 2.0–2.4 mm round line. General estate and garden work: 2.4–2.7 mm. Heavy grass, weeds and young scrub: 3.0 mm and above, where square or serrated profiles cut cleaner than round. Do not overload a head with thicker line than it is rated for — the extra drag strains the clutch and gearbox. Our trimmer line guide covers profiles in detail.

Which Head for Which Job

For general maintenance around homes, gardens and estate roadsides, a bump-feed head with 2.4 mm line is the sensible default — cheap to run and forgiving. For contractors and cane-field edges where line breaks on stones and wire are hourly events, a fast-load head pays for itself in a week of saved reloading stops; the 7-metre capacity universal version suits bigger machines. For clearing heavy overgrowth before it is cut properly, step up to a heavy-duty bump head with 3.0 mm line, or switch to a blade.

Keeping the Head Alive

Heads wear at the eyelets and the bump knob — both are cheap spares, and a worn eyelet is what frays line at the exit point. Keep the spool area clean of packed grass and soil, and store line out of the sun: UV makes nylon brittle within a season. Soaking a stiff spool of line in water overnight restores flexibility noticeably.

Featured Trimmer Heads from Pentales Ltd

Each link below opens the product page on pentalesltd.com. Prices include VAT.

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