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

Panel weight: Up to 200 lbs per panel with the standard steel wheels. Four panels works out to 800 lbs across the system, though that's the per-panel rating multiplied out rather than a separate limit. With the Delrin wheel upgrade, the limit is 100 lbs per panel — check your panel weight against that before selecting it.

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

Panel thickness: 1-3/8 in to 2-1/4 in — select your range above. Because the J-strap bolts through the panel face, carriage bolt and lag bolt lengths differ between the two builds, so the selection matters. For thinner panels, 1-1/4 in to 1-3/8 in, standard duty is the right tier.

Wheels: Color-matched steel ships standard and carries the full 200 lbs per panel. Delrin is available as an upgrade for quieter operation, in black only, rated to 100 lbs per panel.

Panel width: Sized on total panel width — all four panels combined — rather than the rough opening. See the sizing section below for formulas and worked examples.

Panel height: Opening height + 1 in. That leaves 5/8 to 1-1/4 in of floor clearance, adjustable at the wall-mounted pivots during installation — useful over uneven flooring or thick carpet.

Ceiling clearance above door: 6-1/2 in required between the top of the door panels and the ceiling — 1 in more than standard duty, because of the heavier pivot and hanger assembly. Measure before committing to a tier.

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

Room depth on both stack sides: When the panels fold open they swing perpendicular to the wall, so each folded stack reaches into the room by the panel width plus 1/2 in — on 27 in panels that's 27-1/2 in per side. At heavy duty panel sizes this is a real footprint on both sides of the opening. Check that nothing occupies either one.

Wall header: A 1×6 hardwood header board is the minimum for every installation — oak, maple, or poplar, not pine. It spreads the load and decouples the track's bolt spacing from your stud spacing, since the track's mounting holes rarely line up with studs. At 200 lbs per panel across four panels this matters more than anywhere else in the bifold line, and the board must run continuously across any track joint. Extend it past the track to the next stud or structural support point on each side. Never mount to drywall alone. Ceiling mount is not compatible with bifold hardware, so a solid header is the only mounting route.

Origin: Colorado — made to order by Goldberg Brothers in Littleton

Lead time: 10-15 business days

Finishes: All 17 Goldberg Brothers colors

Weight capacity: 200 lbs per panel with steel wheels — 800 lbs across four panels · 100 lbs per panel with the Delrin upgrade

Panel thickness: 1-3/8 in to 2-1/4 in — two builds, select yours above

Maximum panel size: 48 in wide × 108 in tall

Track lengths: 48 in, 56 in, 60 in, 64 in, 72 in, 80 in, 84 in, 96 in, 112 in, 120 in, 128 in, 144 in, 168 in, 192 in

Track sections: Anything over 7 ft 6 in ships in multiple sections with joining plates included

Wheels: Color-matched steel standard · Delrin available as an upgrade, black only, 100 lbs per panel

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

Door-to-wall clearance: 1/2 in

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

Pivot type: Wall-mounted sidewall bracket and plate — two sets included, one per side

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

Trim clearance: Spacers included — clears trim projecting up to 1/2 in

Soft close: Not available for any bifold configuration

Ceiling mount: Not compatible with bifold hardware

Returns: The listed track lengths are stock sizes and return under the standard window — 25 days from delivery with pre-approval and a 25% restocking fee. Designer colors are custom orders and can't be returned, which leaves 8 of the 17 colors returnable. See our return policy

Warranty: Limited lifetime warranty against manufacturing defects. Hardware is sold as rustic-finished, so minor marks and patina are characteristic rather than defects.

For bifold sizing across all six configurations see our bifold measuring guide. For general pre-order measurements see our measuring guide.

The 4-door biparting kit is two complete heavy duty 2-door sets — one for each side — plus an alignment plate set for the center panels. Contents vary by the door thickness you select above.

For 1-3/8 in to 1-3/4 in panels:

• Pre-punched track (1), in your selected length — supplied in multiple sections with joining plates on lengths over 7 ft 6 in
• Fixed J-strap hangers (2) · Loose J-strap hangers (2) — one fixed and one loose per side
• 2 in carriage bolts (8) · 2-1/2 in carriage bolts (8) · hex nuts (8) · lock washers (8)
• Hex bolts (4) · 3/8 in spacers (2) · flange nuts (4)
• Hinges (8 — 6 used for panels 7 ft tall or under, all 8 for taller panels) · 1 in hinge screws (48)
• Sidewall brackets (2) · sidewall pivot plates (2) — one set 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 (10) · fender washers (10) · 1-5/8 in wood screws (10)
• 1/2 in spacers (20) · 1-1/4 in spacers (10)
• Wrenches (2)
• Alignment plate set (1 set, 2 pieces) with wood screws
• Two 7 in pull handles, one per side

For 2-1/4 in panels:

• Pre-punched track (1), in your selected length — supplied in multiple sections with joining plates on lengths over 7 ft 6 in
• Fixed J-strap hangers (2) · Loose J-strap hangers (2) — one fixed and one loose per side
• 3 in carriage bolts (8) · hex nuts (8) · lock washers (8)
• Hex bolts (4) · 3/8 in spacers (2) · flange nuts (4)
• Hinges (8 — 6 used for panels 7 ft tall or under, all 8 for taller panels) · 1 in hinge screws (48)
• Sidewall brackets (2) · sidewall pivot plates (2) — one set 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)
• 6 in hex lag bolts (10) · fender washers (10) · 1-5/8 in wood screws (10)
• 1/2 in spacers (10) · 7/8 in spacers (10) · 1-1/4 in spacers (10)
• Wrenches (2)
• Alignment plate set (1 set, 2 pieces) with wood screws
• Two 7 in pull handles, one per side

The thicker panel build uses longer bolts throughout — 6 in lag bolts rather than 5 in, and 3 in carriage bolts rather than the 2 in and 2-1/2 in pair — because the extra panel thickness has to be spanned before the fastener reaches solid backing.

The fixed hanger on each side attaches to the pivot-side panel. The loose hanger attaches to the center-facing panel and travels freely along the track as the doors fold open. The alignment plate attaches at the bottom of the two center-meeting panels to keep them aligned when closed.

Trim clearance spacers are included in both builds, for standing the track off the wall to clear projecting casing or baseboard up to 1/2 in. Nothing extra to select.

Fastener finish: clear zinc with Raw Steel, Silver Metallic, and PC Chrome; black oxide with Matte Black Texture, Bronze Texture, Black, and Arch Bronze; powder coated to match on the remaining ten colors — Jacob's Gold, Rustic Brown, Regal Red, Rocket White, Blue Ribbon, Flint Gray Texture, Dark Gray Texture, White Bronze Texture, Silver Vein, and Copper Vein. The J-strap is face-mounted, so the bolt heads sit on the panel faces and are visible once installed, along with the lag bolts securing the track to the wall. On the seven finishes that don't ship matched, the touch-up paint option lets you paint them.

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 and trim clearance spacers. 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 doors are operated from both sides — browse our flush pulls collection
• Delrin wheel upgrade: Quieter than the standard steel wheels, black only, and limited to 100 lbs per panel — select it above if your panels are within that
• Touch-up paint: For painting the visible bolt heads on finishes that don't ship matched — select it in the options above

4-door biparting sizing is based on total panel width — all four panels combined — not the rough opening. The track length you select equals your total panel width. For a full walkthrough of all six configurations 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

Because biparting splits symmetrically from the center, the installation looks balanced when open without the extra planning a symmetrical one-way setup needs.

The track lengths listed in the options above are stock sizes, 48 in through 192 in. They ship as ordered and return under the standard 25-day window. Note that 192 in of track is four 48 in panels, which is this kit's maximum panel width — if your calculation runs past 192 in total, you need more panels in a larger configuration rather than a longer track. Lengths over 7 ft 6 in ship in multiple sections with joining plates included, and your header board needs to run continuously across the joint.

For a length outside those options, email us at info@thebarndoorhardwarestore.com — priced the same as the next standard size, but a track cut to order is a custom order and can't be returned, so confirm your measurement first.

Goldberg Brothers hardware uses sealed bearings that run dry. Do not lubricate the track or rollers. Silicone spray, WD-40, and white lithium grease all attract dust, build up in the channel, and make the doors harder to fold, not easier. If the panels start to drag or squeak, the cause is almost always debris in the track or a pivot that needs adjusting — wipe the track channel with a dry cloth and check that the hardware is still tight. On a bifold, also check the hinge screws, since folding puts repeated load on them, and more so at these panel weights.