The parts
Front, back, two sleeves. A rib collar, two rib cuffs, a rib hem. Optionally a V-insert at the front neck, which is a heritage detail that used to absorb neck stretch and now mostly signals a reference to the garments that needed it.
That's the whole garment. Everything that distinguishes a good crewneck from a poor one lives in proportions and in the three rib joins.
Where crewnecks go wrong
The neck rib ratio. Same problem as a t-shirt but more visible, because a heavier body fabric shows a rippling collar more. Around 85 to 92 % of the opening for a sweat weight — heavier bodies want slightly less pull than a light jersey does. And the rib's recovery decides the exact figure.
Hem rib versus body sweep. A hem rib at 85 % blouses the body and gives the classic shape. At 95 % it barely gathers and the garment reads boxy and modern. At 75 % it pulls the body in and looks like a garment that shrank. All three are choices, and only one of them is usually intended.
Sleeve length measured to the wrong place. On a ribbed cuff, sleeve length is measured to the bottom of the cuff, not to the sleeve panel's edge. Get this wrong and the sample arrives with sleeves a full cuff-height too long — a common and entirely avoidable round.
Shoulder seams untaped. In a heavy fabric the shoulder carries the weight of the whole garment. Untaped, it stretches, and the neckline widens over a year. Tape is cheap.
Set-in or raglan
Both are standard on crewnecks and they read completely differently. A set-in shoulder gives a defined line and a more structured garment; a raglan gives movement, a softer shoulder and the option of colour-blocking the sleeves. Raglan is also more forgiving across a size range, which matters if you're grading wide. The full comparison.
Fabric
280 to 400 g/m², terry or fleece. For a crewneck specifically, terry is the more interesting choice more often than for a hoodie: without a hood to hold up, the weight is doing less structural work, and a 300 g/m² terry crewneck is a genuinely three-season garment where the fleece equivalent is a winter one.
The rib is a separate fabric at a matched or slightly heavier weight. A 220 g/m² rib against a 320 g/m² body looks right; a 180 g/m² rib against the same body looks thin at the join.
What to write on the tech pack
Thirteen to sixteen points of measure. The ones a crewneck adds over a t-shirt: cuff width and height relaxed, hem rib height, and sleeve length taken to the bottom of the cuff. Then the three stretch ratios — neck, cuffs, hem — because they aren't derivable from the widths. Where the tape goes for each.
French terry · fleece · the rib · the hoodie built on this · the garment catalogue