J Top Mount Heavy Duty Bifold Barn Door Hardware Kit | 8 Door Biparting

Panel weight: Up to 200 lbs per panel · 1,600 lbs total system (8 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. For a fully clear opening, 10 in of clear wall is needed on each side — four panels fold into two 2-panel folds per side, each taking 5 in of depth, for 10 in per side. A minimum 1/2 in clearance is also required between the end of the track and any adjacent wall on each pivot side — this allows the pivot-side panels to rotate freely during operation.

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 · 1,600 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)

Hanger style: J top mount only — required for 4-panel-per-side stacks

Pull handles: Two 7 in pull handles included — one per side on the outermost panel

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 8-door biparting kit includes two complete heavy duty 4-door one-way 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
• 4 rolling hangers/rollers · 2 fixed pivot hangers (6 hangers total) — all attach to the top edge of the door panels via wood screws
• Anchors and screws for top-edge hanger attachment
• Hex bolts and flange nuts for roller assembly
• Hinges and hinge screws — 6 sets (3 per side, connecting 4 panels on each side)
• Sidewall pivot brackets and plates (2 sets) — wall-mounted heavy duty pivot assembly, 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
• 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 — on the outermost panel of each side)

The fixed pivot hanger on each side attaches to the outermost panel at the pivot wall. All eight panels connect in a chain by hinge sets at each fold point. No hardware mounts to any 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.

8-door biparting sizing is based on total panel width — the combined width of all eight 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) ÷ 8
Example: 120 in opening → total = 124 in → each panel = 15.5 in, round up to 16 in

Fully clear opening (recommended) (equal overlap on both sides, opening fully unobstructed when open):
Total panel width = opening + 20 in · Each panel = (opening + 20 in) ÷ 8
Example: 120 in opening → total = 140 in → each panel = 17.5 in, round up to 18 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.