The RSI SmartCap isn’t your average truck topper. As the world’s first modular stainless steel cap system, it’s designed to adapt to your lifestyle—whether you’re building out a mobile kitchen, securing jobsite tools, or gearing up for off-grid adventure.
Thanks to this revolutionary design, it's easy to install and customize the setup. However, there are still a few spots where it pays to slow down and double-check.
To help you steer clear of frustration, we built out this guide. We’ll walk through the DIY assembly and installation process, using a 3rd-gen Toyota Tacoma as our example, and highlight the tools, tips, and torque specs you’ll want to know to ensure everything fits, seals, and functions exactly as it should.
NOTE: Some newer SmartCap models use a 3-piece roof panel design instead of a single-panel top. While this simplifies shipping (everything fits in one box), it does change the assembly order and adds a few extra steps. This guide covers both versions—so be sure to follow the steps that match your model.
Before You Begin
Before diving into the install, let’s make sure you’re set up for success.
Prep Your Workspace
Take a few minutes to get your workspace in order. It’ll keep the process moving smoothly and help you avoid hunting down parts or tools mid-install.
- Clear a clean, flat work area with plenty of room to move around.
- Make sure all your tools are present, accounted for, and within easy reach.
- Don’t toss the packaging! SmartCap actually incorporates it into the install process to protect your panels.
- Remember, this is a two-person job—minimum, and you’ll need four people when it’s time to lift the SmartCap onto the vehicle.
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Read through everything before you start. From packaging inserts to install guides to warranty literature—grab a drink, plant yourself in a comfy seat, and give everything a once-over so you know what to expect.
Assemble Your Tools
Stick to the recommended tools. The wrong one can damage your SmartCap components.
- Socket Wrench (10mm & 13mm)
- Combination Wrench (10mm & 13mm)
- Torque Wrench (10mm & 13mm)
- Utility Knife
- Scissors
- Super Glue
Check All Components
Your kit contents will vary slightly based on which roof design you ordered.
- Single-Panel Roof Design: You'll receive two boxes—one with the roof, and one with everything else. You should see five major components: Front Flange, Rear Flange, Left Panel, Right Panel, Roof Panel.
- Three-Piece Roof Design: All panels are nested in a single box. You should see seven major components: Front Flange, Rear Flange, Left Panel, Right Panel, Center Roof Panel, Left Roof Panel, Right Roof Panel.
IMPORTANT! Inspect every painted panel before you start. SmartCap won’t accept paint-damage warranty claims after assembly. If anything’s missing, damaged, or just looks off, stop the install and contact support: SUPPORT.NA@SMARTCAP.COM.
Count All Hardware
Your kit comes fully stocked—so don’t get clever with substitutions. Double-check that the following are present:
Assembly Hardware
- M6 Bolt – 30x
- M6 Lock Washer – 30x
- Fastener Block Clamp – 30x
- Fastener Block – 30x
- D-Rubber – 1x
- Spare Parts – 2x
Pre-Fastened to Roof Panel
- M6 Fender Washer – 10x (Short Bed) / 12x (Standard Bed)
- M6 Lock Nut – 10x (Short Bed) / 12x (Standard Bed)
NOTE: If you ordered the 3-piece roof system, you'll see 42 of each fastener instead of 30. Everything else is the same.
Install Hardware
- Thin Rubber Pad – 6x
- Thick Rubber Pad – 8x
- Mounting Clamp – 6x
- Third Brake Light T-Harness – 1x
SmartCap Assembly Overview
Once you’ve checked your parts, prepped your workspace, and gathered your tools, you’re ready to get started. Below, we’ve broken down the install into key phases, organized by assembly milestones. Our goal is to give you the big-picture purpose behind each step, along with common “gotchas” and tips to save you time (and frustration).
Need more detail? SmartCap’s Mobile Instruction Guides offer loopable, step-by-step videos backed by written directions and illustrations. Just scan the QR code inside your Fitment Kit (the box with your hardware) to open the guide on your phone or tablet. It’s a great visual backup if you want to double-check a step mid-install—or if you simply prefer to watch it in action.
IMPORTANT! If your SmartCap has a 3-piece roof panel, the assembly steps differ from the standard, single-panel model. Skip ahead to Three-Piece Roof Assembly for the correct instructions. Once your cap is assembled, rejoin us in the Install Overview—those steps are the same for both designs.
Single-Panel Roof SmartCap Assembly
Step 1: Attach Side Panels to Roof
Remove the top lid of the box and lay it upside down next to the base. This will serve as a padded work surface to help prevent scratches while handling other panels. Peel back the protective plastic on the roof panel, but leave the component in the bottom of the box to keep it stable and protected while you work. Note: the roof panel’s rear is marked by the air vent.
Use a 10mm combination wrench to remove the pre-installed lock nuts and fender washers from the roof panel and set them aside.
With two people, carefully lift the right-side panel from the packaging and bring it to your work area. One end of the panel will be slanted—this should face the rear (i.e., toward the air vent). Line up the tabs on the top of the side panel with the narrow slots on the roof panel and insert them. Tap firmly with the palm of your hand until the gap between panels is minimal, ideally just 2–3mm.
Once seated, reattach the M6 fender washers (rounded side down, to protect the paint) and M6 lock nuts. Hand-tighten them for now, just to hold everything in place.
Repeat the process with the left-hand panel. Again, remember that the slanted edge goes toward the rear air vent.
Step 2: Attach Front & Rear Flanges
With the roof panel still upside down and the side panels loosely installed, it’s time to attach the front and rear flanges.
Start with the front flange. Carefully remove it from the packaging, being mindful not to damage the attached gasket. Align the front flange with the roof panel, ensuring the edges are flush and keeping in mind that the rear of the roof is marked by the air vent.
Using the provided hardware and referring to the manufacturer’s diagram in your fitment kit, begin inserting the fasteners—starting in the middle and working outward. For each fastener:
- Insert the fastener and hand tighten the fastener block and clamp.
- Add a lock washer and M6 bolt.
- Make sure the bolt head is oriented toward the inside of the cap, so you’ll have room to tighten it with a socket or box wrench.
Once the front flange is installed, repeat the same process for the rear flange, starting from the middle and working outward, following the diagram for fastener placement.
After both flanges are installed, torque each front and rear flange bolt to 5 Newton Meters (Nm) or 3.7 ft-lbs. Do not overtighten! If any hardware begins to deform or bow, stop tightening and back off slightly. Finish by torqueing the M6 lock nuts on the side panels to the same 5 Nm (3.7 ft-lbs).
Step 3: Fit the D-Rubber Seal
Now that the side panels and front/rear flanges are attached to the roof, it’s time to install the D-rubber gasket—your final step before flipping the SmartCap over and mounting it to the vehicle.
Clean the surface where the gasket will sit using an alcohol wipe to ensure proper adhesion. Check that the end of the D-rubber has a clean, square cut. If not, trim it with scissors.
Next, locate the two retention tabs on the rear flange—one near each corner—and bend both upward to about a 45-degree angle. These will anchor the D-rubber gasket at either end.
Starting at the right-side (passenger-side) tab, peel away 6–12 inches of the adhesive backing and slide the D-rubber onto the bent tab. The flat side of the “D” should align with the cap flange, and the rounded portion should lightly press against the rear door gasket.
Apply a short 3-inch bead of super glue along the curve of the cap, near the retention tab and about ⅛" in from the outer edge of the flange. Working slowly along the curve of the cap, press the gasket firmly in place, avoiding kinks. Press the retention tab back down.
Continue working your way around the cap, maintaining a consistent ⅛" in gap from the edge. When you reach the second (left/driver-side) retention tab, dry-fit the gasket to ensure a neat overlap, then trim the end square. Remove the rest of the adhesive backing, apply another 3-inch bead of glue to the cap’s corner, and press the gasket into place over the tab. Finally, bend the second retention tab back down to ensure both are securing the gasket in place.
Once the D-rubber is fully seated and secured, you’ll add the included rubber pads. These thick adhesive-backed pads go on the inside of the D-rubber—right where it will contact the top edge of your truck bed. Check the diagram in your PDF for exact placement, then peel and stick each pad at the indicated locations.
Three-Piece Roof SmartCap Assembly
If you are installing a three-piece roof system, follow these steps for cap assembly. They differ slightly from the single-panel setup. If you’re ready for installation, jump to Step 4.
Step 1: Assemble the Roof Panel
Unfold the cardboard that is holding the side roof panels in the box and lay it on the ground. We will use this as a soft cushion to assemble the cap on top of. Inside the box, you’ll also find extra cardboard dividers and corner stiffeners. Lay these out as instructed in the SmartCap install guide and videos to protect the side panels as you unpack and stage them for install.
Use the supplied fastener block hardware from your fitment kit to connect the left and right roof panels to the center roof panel. For each connection, loosely install a fastener block and clamp, a lock washer, and an M6 bolt. Ensure that the bolt heads are oriented outward—this provides clearance for your wrench during final tightening. Once aligned, torque each bolt to 5 Nm (3.7 ft-lbs). Do not overtighten.
Now, place the rest of the fastener blocks on each end of the roof panel. Remove the M6 lock nuts and fender washers pre-installed on the roof panel and set them aside.
Step 2: Add the Sides & Flanges
With two people, carefully lift the left-side panel from the packaging and bring it to your work area. One end of the panel will be slanted—this should face the rear (i.e., toward the air vent). Line up the tabs on the top of the side panel with the narrow slots on the roof panel and insert them. You may need to tap firmly with the palm of your hand until the gap between panels is minimal, ideally just 2–3mm.
With one person supporting the side panel, the other person should take the front flange out of its packaging and line it up with the roof panel—ensuring they are flush with one another and taking care not to damage the gasket on the flange. Starting in the middle and working outward, loosely tighten the fastener blocks. Refer to the manufacturer’s diagram in your fitment kit for the correct fastener order and placement.
For each fastener:
- Insert the fastener and hand tighten the fastener block and clamp.
- Add a lock washer and M6 bolt.
- Make sure the bolt head is oriented toward the inside of the cap, so you’ll have room to tighten it with a socket or box wrench.
Once the front flange and left-side panel are secured, repeat the same process to attach the right-side panel. Then, attach the M6 fender washers (rounded side down, to protect the paint) and M6 lock nuts. Hand-tighten them for now, just to hold everything in place. With both side panels in place, insert the remaining fastener blocks and loosely tighten.
Again, using two people, grab the rear flange and bring it to your work area. Line it up with the cap and, starting from the corners, loosely tighten the fastener blocks. Be sure to follow the diagram for correct fastener order of assembly.
Once both flanges are securely in place, it’s time to tighten everything up:
- Following the same order from the diagram, torque each front and rear flange bolt to 5 Newton Meters (Nm) or 3.7 ft-lbs.
- Do not overtighten—if any washer, clamp, or flange begins to deform or bow, stop tightening and back off slightly.
- Finish by torqueing the M6 lock nuts on the side panels to the same 5 Nm (3.7 ft-lbs).
Step 3: Fit the D-Rubber Seal
With the side panels and flanges now attached to the roof, it’s time to install the D-rubber gasket—your last step before flipping the SmartCap over for vehicle installation.
Clean the surface where the gasket will sit using an alcohol wipe to ensure proper adhesion. Check that the end of the D-rubber has a clean, square cut—trim it with scissors if needed.
Locate the two retention tabs on the rear flange (one near each corner) and bend them upward about 45 degrees. These will anchor the gasket at both ends.
Starting at the right-side (passenger-side) tab, peel back 6–12 inches of adhesive and slide the D-rubber onto the bent tab. The flat side of the “D” should align with the flange, while the rounded side should lightly press against the rear door gasket.
Apply a short 3-inch bead of super glue along the curve of the cap, near the retention tab and about ⅛" in from the outer edge of the flange. Working slowly along the curve of the cap, press the gasket firmly in place, avoiding kinks. Press the retention tab back down.
Continue working your way around the cap, maintaining a consistent ⅛" in gap from the edge. When you reach the second (left/driver-side) retention tab, dry-fit the gasket to ensure a neat overlap, then trim the end square. Remove the rest of the adhesive backing, apply another 3-inch bead of glue to the cap’s corner, and press the gasket into place over the tab. Finally, bend the second retention tab back down to ensure both are securing the gasket in place.
Once the D-rubber is fully seated and secured, you’ll add the included rubber pads. These thick adhesive-backed pads go on the inside of the D-rubber—right where it will contact the top edge of your truck bed. Check the diagram in your PDF for exact placement, then peel and stick each pad at the indicated locations.
SmartCap Installation Overview
You’ve assembled your cap, so now it’s time to install it on your truck bed. You’ll need a 13mm socket wrench, a combination wrench, and a torque wrench to complete the next steps—and four people to lift the cap into place.
Step 4: Connect Third-Brake Light Wiring
Disconnect the extension harness from the SmartCap and set it aside. Using a 13mm socket wrench, remove the three bolts securing the driver’s side taillight assembly. Gently place the taillight on the tailgate—do not disconnect any existing wiring.
Carefully lift the top edge of the bed cap and locate the factory hole in the sheet metal. Feed the thick end of the extension harness through this hole toward the taillight cavity, then fish it out the other side.
From the fitment kit, grab the T-harness. Disconnect the middle brake light plug on the back of the taillight assembly, and connect it to the female plug on the T-harness. Plug the male end of the T-harness into the taillight.
Now connect the T-harness to the extension harness you routed through the sheet metal. Coil any excess harness length, secure it with zip ties, and tuck it neatly into the taillight cavity. Reinstall the taillight assembly.
Step 5: Position SmartCap on Truck Bed
Because of its size and weight, you’ll need at least four people to safely lift and position the SmartCap. Walk the cap into place and set it down carefully. Avoid sliding it across the bed rails to prevent dislodging the D-rubber seal. In fact, walk around the truck to check that the D-rubber is properly seated, with the lip tucked fully underneath the cap along all edges.
Once the cap is centered and properly aligned on the bed rails, it’s time to install the mounting clamps.
Start by placing the thin rubber pads on top of the bed rails—these protect the SmartCap’s finish where clamps will apply pressure. Except at the rear corners, position each pad next to a gusset on the cap (three pads per side).
Next, disassemble the mounting clamps. Insert the lower clamp arms into the bed rail track and align each one underneath a rubber pad. Reassemble the upper and lower clamp arms, hand-tightening each clamp over its corresponding pad.
When all clamps are in place, tighten them to 6 Nm (4.4 ft-lbs) using a torque wrench and a 13mm socket.
Finally, reconnect the extension harness to the SmartCap’s third brake light harness. That’s it—your SmartCap is fully installed and ready to roll!
Final Checks Before You Call It Done
- Start the truck. Some models may take up to 30 seconds to detect the new SmartCap connection.
- Test the lights. Confirm the brake lights and turn signals are connected and functioning properly.
- Check all doors. Make sure they open and close smoothly and sit flush with the panels.
- Inspect alignment. Confirm the rear flange and all doors are level and evenly mounted.
- Look for gaps. Check for gaps around the tailgate and bed rails—adjust clamps or spacers as needed.
- Verify weatherproofing. Confirm that D-Rubber seals are seated correctly and that Butyl Tape and foam strips are in place if needed.
- Test the pressure locks. If a door doesn’t close flush, adjust the lock tension. Regular tweaks are recommended for heavy use.
Order Your SmartCap with Confidence from Parts Via
SmartCap is built to handle real-world abuse—and installing it is well within reach for most DIYers with basic tools and a little patience. If you’d rather leave it to the pros, Parts Via also offers dealer installation options for added peace of mind. Plus, our fast, FREE ship-to-store option lets you save big on delivery costs by picking up your SmartCap at a local retailer.