J Top Mount Heavy Duty Bifold Barn Door Hardware Kit | 4-Door Biparting

Panel weight: Up to 200 lbs per panel · 800 lbs total system (4 panels). For panels under 100 lbs each, Delrin wheel upgrade is available (black finish only) for quieter operation.

Panel width: Sized based on how much coverage you need over the opening — see the panel sizing section below for formulas and worked examples.

Panel height: Opening height + 1 in. Leaves 5/8 to 1-1/4 in of floor clearance, adjustable at the wall-mounted pivots during installation.

Panel thickness: 1-3/8 in to 2-1/4 in. For thinner panels (1-1/4 to 1-3/8 in), standard duty hardware is the right choice.

Maximum panel size: 48 in wide × 108 in tall per panel.

Ceiling clearance above door: 6-1/2 in required between the top of the door panels and the ceiling.

Wall clearance — both sides: Biparting requires clearance on both sides of the opening. For a fully clear opening, 5 in of clear wall is needed on each side — two panels stack to just 5 in of depth. Minimum 1/2 in between the track end and any adjacent wall or trim on each pivot side.

Wall header: A solid header above the opening is required for track mounting. If there is no existing header or backing in the wall, we recommend installing a minimum 1×6 hardwood board (3/4 in thick × 5-1/2 in wide) that extends past the length of the track to the next stud or structural support point on each side. Ceiling mount is not compatible with bifold hardware.

Brand: Goldberg Brothers — made to order in Colorado, USA

Lead time: 10–15 business days

Finishes available: All 17 Goldberg Brothers powder coat finishes

Weight capacity: 200 lbs per panel · 800 lbs total system

Panel thickness: 1-3/8 in to 2-1/4 in

Maximum panel size: 48 in wide × 108 in tall

Ceiling clearance: 6-1/2 in above door panels

Floor gap: 5/8 to 1-1/4 in — adjustable at the pivots during installation

Pivot type: Wall-mounted sidewall bracket and plate (2 included — one per side)

Pull handles: Two 7 in pull handles included — one per side

Wheels: Steel (standard) · Delrin upgrade available for panels under 100 lbs each, black finish only

Soft close: Not available for bifold hardware

Ceiling mount: Not compatible with bifold hardware

Warranty: Limited lifetime warranty

For bifold-specific sizing formulas see our bifold measuring guide. For general pre-order measurements see our measuring guide.

The 4-door biparting kit includes two complete heavy duty 2-door roller sets — one for each side — plus an alignment plate set for the center panels.

• Pre-punched track (1) — custom cut to your specified length
• Fixed J top mount hangers (2) · Loose J top mount hangers (2) — one fixed and one loose per side, both attach to the top edge of the door panel via wood screws
• Anchors (8) and screws (8) for top-edge hanger attachment
• Hex bolts · 3/8 in spacers · flange nuts for roller assembly (doubled quantities)
• Hinges (8 — 6 used for panels 7 ft tall or under, all 8 for taller panels) · 1 in hinge screws (48)
• Sidewall pivot brackets and plates (2 sets) — wall-mounted, one per side
• Door bottom plates (2) · pivot pins (2) · 5/16 in lock washers (2) · 5/16 in nuts (2)
• Track stops (2) · rubber bumper bands (2) · felt strips (2)
• 5 in hex lag bolts · spacers · fender washers · wood screws (doubled quantities)
• Wrenches (2)
• Alignment plate set (1 set — 2 pieces) · wood screws for alignment plate — attaches at the bottom of the two center-meeting panels to keep them aligned when closed
• Two 7 in pull handles (1 per side)

The fixed hanger on each side attaches to the top edge of the pivot-side panel. The loose hanger attaches to the top edge of the center-facing panel and travels freely along the track as the doors fold open. No hardware mounts to either door face.

A latch and flush pull are not included — add them before ordering to avoid a second shipment. Soft close is not compatible with bifold hardware.

This kit includes two 7 in pull handles. A latch and flush pull are not included:

Latch: Keeps the door closed deliberately — browse our latches collection

Flush pull: For the wall-facing side if the door is operated from both sides — browse our flush pulls collection

Delrin wheel upgrade: For panels under 100 lbs each — quieter than the standard steel wheels. Available in black finish only.

4-door biparting sizing is based on total panel width — the combined width of all four panels — not the rough opening. The track length you select should equal your total panel width. For a full walkthrough see our bifold measuring guide.

Minimum coverage (doors close over the opening with a small overlap on each side):
Total panel width = opening + 4 in · Each panel = (opening + 4 in) ÷ 4
Example: 96 in opening → total = 100 in → each panel = 25 in

Fully clear opening (recommended) (equal overlap on both sides, opening fully unobstructed when open):
Total panel width = opening + 10 in · Each panel = (opening + 10 in) ÷ 4
Example: 96 in opening → total = 106 in → each panel = 26.5 in, round up to 27 in

Goldberg Brothers tracks are custom-cut to your specified length. If the size you need isn't listed, email us at info@thebarndoorhardwarestore.com — custom lengths are priced the same as the next standard size.