Fabrics & GSM · Hoodie Encyclopedia
Heavyweight 500 GSM Fleece
Heavyweight fleece is the fabric behind the streetwear hoodie people remember touching. It stands away from the body, the crown of the hood holds shape when down, and the sleeves fall with weight. Getting from 320 GSM to 500 GSM is not just more yarn — it's a different construction discipline.
Why 500 GSM matters
Weight-per-square-metre is a proxy for yarn density. At 500 GSM the fleece contains almost double the yarn per m² of a 280 GSM terry — the fabric drapes like a garment, not like a t-shirt. Streetwear brands moved to 400+ GSM because customers can feel the difference through a polybag.
400 vs 450 vs 500 GSM
| GSM | Hand-feel | Best use |
|---|---|---|
| 400 gsm | Substantial but flexible | Premium everyday hoodie; sits between mid and heavy |
| 450 gsm | Streetwear standard | Oversized fits; drops without collapsing |
| 500 gsm | Blanket-like | Statement heavyweight; luxury drops |
| 550+ gsm | Rare, semi-boardy | Special limited runs; requires custom knitting |
Construction rules for heavy fleece
- Seam allowance — increase from 8mm to 10–12mm; the fabric bulk needs more grab.
- Needle size — 90/14 or 100/16; standard 80/12 skips stitches on 500 GSM.
- Thread — Tex 40 or 60 polyester; regular Tex 27 snaps under seam stress.
- Rib — 2x2 with 5% elastane; 2x1 rib gets pulled out of shape by the weight of the sleeve.
- Kangaroo pocket — jetted or flat set-in; avoid triple-layered patch pockets that create bulk.
- Hood — 3-panel with gusset only; 2-panel hoods collapse under their own weight.
Cost & MOQ implications
500 GSM fleece is 40–60% more fabric per garment than 280 GSM terry. Fabric MOQs also climb: mills usually require a 300–500m minimum knit run for heavyweight qualities, which lifts the effective garment MOQ. Yield loss is higher too — heavy fleece is trickier to lay flat, so marker efficiency drops 3–5 points.
Common pitfalls
- Under-shrinking the fleece — 500 GSM shrinks 5–7% in the first wash; if the mill hasn't pre-shrunk, size charts break.
- Using standard weight rib — rib bags at the cuff within 20 wears when body fabric is 500 GSM.
- Cover-stitch tension not adjusted — puckered hem on heavy fleece; machine feeds must accommodate the loft.
- Trying screen print without a base — plastisol ink sinks into 500 GSM nap; use a white underbase or DTF.
Building a heavyweight range?
We'll press a 450 GSM and 500 GSM proto side-by-side within 3 weeks.