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Raglan or Set-In Sleeves on a Heavy Hoodie?

Raglan, set-in or dropped shoulder? What each sleeve does on a heavy hoodie, what the research shows, and which suits life under a winter coat.

Look at where the sleeve meets the body on any hoodie and you'll find one of three answers. A seam that circles the arm at the end of the shoulder bone. A seam that runs on a slant from the collar down to the armpit. Or a seam that hangs a few centimetres down the upper arm, well past the shoulder. Those are set-in, raglan and dropped shoulder sleeves. On a thin T-shirt the difference is mostly looks. On heavy cotton fleece it changes how the thing moves, how it sits under a coat, and which size you should buy.

Here's what each one does, what the research actually shows, and where the usual advice is habit rather than evidence.

The three sleeves, in plain terms

  • Set-in. The sleeve is a separate tube sewn into a round armhole. There's a seam across the top of the shoulder from the neck to the shoulder point, and the armhole seam sits roughly at the end of the shoulder bone. Most tailored jackets and dress shirts are built this way.
  • Raglan. The sleeve runs all the way up to the neckline, so the seam goes diagonally from the collar to the underarm, front and back. There's no seam across the top of the shoulder at all. The name comes from Lord Raglan, a British army commander of the 1850s.
  • Dropped shoulder. A variation on the set-in sleeve. The body is cut wider, so the shoulder line carries on past the bone and the armhole seam lands on the upper arm. This is the boxy shape most heavyweight streetwear uses.

None of these is the "quality" option on its own. A badly sewn raglan is worse than a well sewn set-in sleeve. What changes is where the cloth has to fold and stretch when you move.

What the research actually tested

There's surprisingly little controlled work comparing sleeve types, and we couldn't find any on heavy fleece hoodies. The clearest study is a small one from smart clothing research. In 2021, Goncu-Berk and Guvenc Tuna made fitted T-shirts in both a set-in and a raglan pattern, with textile electrodes built into the upper arm to read muscle signals, and published the results in the journal Sensors. Participants did ten biceps curls with a 2.5 kg dumbbell, timed to a metronome.

The raglan shirts read far cleaner: an average signal-to-noise ratio of 22.5 dB, against 14.0 dB for the set-in shirts, and close to the 21.8 dB from conventional stick-on electrodes. The authors put the gap down to the seam. In their words, the seam on the shoulder joint of the set-in shirt "does not stretch and causes temporary loss of contact between the e-textile electrode surface and the skin during movement." Put simply, the set-in sleeve shifted on the arm as the arm worked. The raglan sleeve, with no seam over the joint, stayed put.

Be clear about what that does and doesn't show.

  • It was five people, in fitted shirts, doing one movement.
  • It measured electrode contact, not comfort, warmth or how long the garment lasts.
  • The shirts were cut close to the body, nothing like a loose heavy hoodie.

So it's real evidence that seam position changes how a sleeve travels with the arm. It is not proof that a raglan hoodie is warmer, tougher or more comfortable. Most of what you'll read online, that raglans "move better" and set-ins "look sharper", comes from pattern cutting practice and sportswear convention. That's not nothing, since cutters have generations of trial and error behind them, but it isn't a tested result.

Why it matters more in heavy cloth

Knit fabric moves by stretching. ASTM International's test method for this, ASTM D2594/D2594M-21, Stretch Properties of Knitted Fabrics Having Low Power, measures how far a knit stretches under a known load and how much it grows and fails to recover afterwards. Its significance section notes that in loose-fitting "comfort stretch" apparel, a momentary stress occurs "when a fabric is required to accommodate movement." That's the job a sleeve does every time you reach for a shelf.

A dense, heavy fleece usually gives less than a thin jersey, so more of the work of moving falls to the cut. With a set-in sleeve and a fairly high armhole, lifting your arm pulls on the shoulder seam and drags the body and hem up with it. With a raglan, the shoulder is one continuous piece of cloth from collar to cuff, so it folds rather than pulls. With a dropped shoulder, there's so much cloth under the arm that reaching is easy, but that extra fabric has to go somewhere when your arm is down.

The seam itself matters as much as where it sits. ASTM D6193-16(2025), Standard Practice for Stitches and Seams lists five characteristics of a properly constructed seam: strength, elasticity, durability, security and appearance. It also says the elasticity of a seam "should be slightly greater than that of the material which it joins." A seam stiffer than the cloth around it is where the strain collects. That applies to every sleeve type, and it's worth more attention in the shop than the sleeve shape.

Wearing it under a coat

This is the part that matters in October. From now until April, a heavy hoodie spends a lot of its life under a shell or a parka, and the sleeve type decides how well the two get along.

  • Set-in is the trimmest under a fitted coat. There's no spare cloth in the armpit, so the coat's sleeve slides over it cleanly.
  • Raglan sits well under most coats and suits anyone who drives, cycles or carries things with their arms up. If the coat is a raglan too, the two sets of seams run the same way rather than fighting.
  • Dropped shoulder puts a fold of heavy fleece in the armpit and down the upper arm. Under a slim jacket that bunches. Under a roomy parka, or as the outer layer on a dry autumn day, it's fine.

One more small thing that nobody has tested, as far as we know, but which is simple geometry. A set-in sleeve has a seam running along the top of the shoulder, which is exactly where a backpack strap sits. A raglan doesn't. If you carry a heavy bag every day, that's worth noticing on the walk home.

How sleeve type changes your size

Size charts usually give a shoulder width. On a set-in sleeve that number means something: it's the distance between the two shoulder seams, and it should land near the end of your shoulder bones. On a raglan there's no shoulder seam to measure. On a dropped shoulder the number is deliberately wider than your body.

For raglan and dropped shoulder pieces, the more useful measurement is sleeve length taken from the centre back of the neck to the cuff. Measure a hoodie you already like the same way and compare. If a cotton hoodie has already shrunk on you, sleeve length is often where you notice it, and whether you can get that back depends on how far it went.

So which one should you buy?

  1. If you lift and reach a lot, stacking wood, climbing, cycling, carrying kids, a raglan gives the most free movement through the shoulder.
  2. If it lives under a fitted coat, or you want a clean, squared shoulder line, go set-in and check the shoulder seam lands at your shoulder bone.
  3. If you want the boxy heavyweight shape and wear it as the outer layer more often than not, a dropped shoulder is the natural cut.
  4. Whatever the shape, look at the seams. Flat, even stitching that stretches with the cloth when you pull it gently matters more than which way the seam runs.

Once you've picked, look after the shoulder the same way you look after the rest. Dry it flat or folded over a rail rather than on a narrow hanger, which stretches a heavy shoulder out of shape whatever the sleeve. Our washing and care instructions cover the rest, and the shop has the current pieces.

Sources

PreviouslyWhy Hard Water Leaves a Hoodie Stiff and Dull NextWhy a Heavy Hoodie Feels Damp in August
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