Gusseted tongue at a glance
- Full gusset
- To the top of the lacing
- Partial gusset
- Part way up
- Keeps out
- Grit, sand and water
What a gusset closes off
On a plain shoe the tongue is a loose flap, and there's an open channel down each side of it. Sand, grit, seeds and water all use that channel. A gusset closes it by joining the tongue to the boot with a folding panel of fabric, the way bellows fold.
Keeping grit out
The immediate benefit is that debris stays out. Anyone who has emptied grit out of a boot mid-hike knows why that matters, and it's a bigger deal on scree and sandy trail than any waterproof membrane. The second benefit is quieter: the tongue can't migrate sideways, so lace pressure stays where you set it instead of drifting off-center over a few miles.
How far the gusset runs
Gussets come in depths. A full gusset runs to the top of the lacing and is what makes a boot genuinely water-resistant to the ankle, which is the point of a waterproof membrane in the first place. A partial gusset stops halfway and keeps grit out while letting water in above that line, which is fine for dry, dusty ground.
What this means when you're choosing
- How high the gusset runs, since a membrane below an open gap does nothing above it
- Whether the gusset fabric is soft enough not to crease into a pressure point
- Tongue padding, which decides whether hard lacing hurts the top of your foot
The common mistake
Expecting a waterproof boot to work with a partial gusset
Water goes in over the top of the gusset, not through the membrane. A boot with a partial gusset is water resistant to the height of that gusset and no further, whatever the membrane inside is called.
Common questions
Does a gusseted tongue make a boot waterproof?
It removes the biggest hole, which is a necessary part of the answer rather than the whole one. A waterproof boot needs the membrane, the gusset and taped seams; a full gusset on a non-membrane boot just keeps grit and splashes out.
Why do trail running shoes usually skip it?
Most don't, actually, at least partially, because grit is a bigger problem when you're running. What they skip is the full-height version, since drainage and low weight matter more than sealing water out.