When you design a wardrobe or dresser, the drawer slide mounting is decided early because it drives the cabinet frame. Side-mount and under-mount are the two families most furniture factories choose between — and the right answer depends on what the drawer must carry and how it should look.
Side-mount: the proven workhorse
Side-mount slides bolt to the drawer sides and the cabinet sides. They tolerate small cabinet-frame tolerances, install quickly, and come in the widest load range — from light 20 kg pairs to heavy-duty 100 kg pairs. Most of our furniture customers use three-section side-mount slides with ball bearings and add soft-close where the buyer expects it.
Under-mount: hidden hardware, visible cost
Under-mount slides attach beneath the drawer and are invisible when the drawer is open — the premium look most bedroom ranges want. They include integrated soft-close in most cases and give a smooth 3/4 or full extension. The trade-offs: tighter side clearance (often 27 mm), less tolerance for cabinet-frame error, and a higher unit price. Under-mount also reduces usable interior width, which matters on narrow drawers.
Load and extension: reading the spec
Side-mount pairs commonly rate 30–45 kg; under-mount pairs rate 30–50 kg depending on rail length. If the dresser drawer will hold folded clothes, either works. If it holds shoes or tools, stay with side-mount ball bearing and confirm the pair rating with your supplier rather than trusting a catalogue number.
Installation and service
Side-mount slides accept more cabinet-frame deviation, so production lines make fewer rework parts. Under-mount slides need a dedicated drawer bottom groove or bracket, adding one step per drawer. For high-volume programs, most OEM and ODM customers standardize on side-mount and reserve under-mount for their premium lines.
The mounting decision is really a cabinet-frame decision: side-mount tolerates production variance and a wider load range, under-mount buys the invisible look and pays for it in clearance and cost. Most furniture factories standardize one side-mount line for volume and reserve under-mount for the premium range. Decide which drawer carries which, and the slide choice follows without rework.
