Rivian R1S Trunk Brackets

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UPDATES

• May 29, 2024 - Added storage bracket to keep a 2x3 riser from falling into the storage area.

Trunk Brackets

I started this by looking for a way to help make it easier to transport lumber/plywood home in my R1S.  I wanted something “simple” to use, so I started with the idea of using 2x3 dimensional lumber to build a couple of rails to raise the lumber/plywood above the height of the tailgate and to keep it off of the 3rd row armrests.  Since the brackets are just 3D printed, they're not strong enough to hang anything off of, but in theory they don't have to be.  They're mostly just trying to keep things upright while you slide lumber inside and then gravity holds everything in place.  The weight of your cargo is supported by the 2x3s.

This quickly evolved to a slightly more generic solution as it became clear you could use this to build a budget-friendly bed frame if you wanted.  So I started designing additional brackets to allow you to join 2x3s in whatever orientation you might need.  The brackets refer to these names:

• end attaches to the end of a 2x3
• flat attaches to the wide side of the 2x3 (2.5")
• vert attaches to the narrow side of the 2x3 (1.5")

Note: The vert-to-vert one could be used to join 2x2s together if that's all you need.

Remember how I mentioned this was supposed to be a “simple” solution?  You could do nearly all of this with half-lap joints cut into each of the pieces and forgo most of the brackets … but that's not as easy as just slapping them all together with printed brackets :)

What do I need?

I've included a bunch of different brackets in the model, but you don't need all of them. They're to give you options, depending on your needs.  Here are some suggested configurations:

Lumber transportation

The tailgate is about 220mm (~8 5/8") tall closed, but will raise another ~13mm (~½") as it pivots open.  So if you want to be able to open/close the tailgate with your lumber loaded, you need a minimum of ~235mm (9 ¼") clearance.  The tall side of a 2x3 is ~64mm (2.5") so your rear vertical supports should be 172mm (6.75").  The pictures were taken with pieces cut to 180mm (~7").

• Rear support
  • PRINT (2x) rail brackets
  • PRINT (4x) rail bracket locks (2 per bracket)
  • PRINT (2x) end-to-flat brackets
  • CUT (1x) 2x3 to 48"
  • CUT (2x) 2x3 to 172mm (6.75") or greater (I used 180mm in pictures)
• Front support
  • PRINT (2x) flat-to-vert brackets
  • CUT (1x) 2x3 to 48" (or up to 52")
  • CUT (2x) 2x3 to 172mm (6.75") (or anything really)

Flat Floor

I discovered that you can use some short lengths of 2x3 lumber as risers to level out the rear floor panel.  I reused the lumber transportation pieces:

• PRINT (2x) storage brackets
• CUT (3) 2x3 to 180mm (~7") length

Install two of the 2x3 pieces on-end, against the sides of the storage compartment (running front-to-back), where the insert sits.  The third one goes along the middle back rail (running side-to-side).  Unfortunately, that one wants to fall into the storage area when you open it up, so install 2 storage brackets to give that piece something flat to rest on.

Sleeping platform

You could build a sleeping platform using the same techniques as above, just adjusting the height of each support.  I'll probably experiment with this some more in the future, but for now I'll leave this as an exercise for you, as a reader.

Printing

• When printing the rail bracket piece (the only one specific to the Rivian), make sure you use 0.20mm layers or something so you get a dimensionally accurate 4.0mm thick bottom plate.  This is required for the twist lock to work properly and hold well.
• Perimeters:
  • I've used 2 perimeters with a 0.4mm nozzle and 1 perimeter on a 0.8mm nozzle (so similar perimeter thickness) and both seem sufficient for light use.
  • Increase the number of perimeters for more strength, as you see fit.
• Enable supports
  • I use grid supports and they break off clean and easy.

Installation

This depends on what you're doing or how you want it configured.  Obviously, just put the pieces together as you see fit.  But here are a couple of minor notes/disclaimers:

Screw/screw holes:

• You MUST add screws between the rail brackets and the vertical supports to provide stability.
• I used basic 1 ¼" wood screws.  DO NOT over-tighten them.  They WILL split the plastic.  Just try to get them flush with the surface.
• There are screw holes in all of the brackets for your convenience, but most are not necessary.

Rail bracket

The easiest way to attach the rail bracket is to:

1. Slide a lock through the rail and twist clockwise 90 degrees until it stops.
2. Raise the lock and slide it along the rail until it engages with one of the notches on the underside.
3. Now slide the bracket into the lock.
4. Slide the second lock into the bracket and rail and twist clockwise.
5. To unlock, twist the locks counterclockwise.

You can store the locks by attaching them to the side of the brackets.  It can help to insert at an angle and twist clockwise to insert and counterclockwise to remove.

Acknowledgements

This project was inspired/influenced by the following:

• https://www.printables.com/model/551407-rivian-r1s-sleeping-platform
• https://www.reddit.com/r/Rivian/comments/1brp415/4_sheets_of_4x8_plywood_18_2x4x8_studs_no_regrets/

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