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Rear Under-trunk Storage Bins in 5-, 6- and 7-seater Model X Versions

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tps5352

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As we know, Model X cargo space varies from car-to-car. While the front trunk ("frunk") space has remained pretty much stable, the maximum volume in the rear trunk/cargo area, behind the rear seats, varies depending on:
  • Number of stock seats (5, 6, or 7) and number of seat rows (2 or 3).
  • Whether second-row rear seats can be folded flat (so by model-year).
  • Use of so-called under-trunk storage compartments (and whether they are used covered or uncovered).
Current five-seater versions have second-row rear split-bench seats that can fold flat--becoming level with the rest of the rear cargo space floor.

Six- and seven-seater versions have second-row seats that either can or cannot fold flat depending on the seat-number version and model-year. (I'll let 6- and 7-seater owners explain all that, if so inclined.) But third row seats can fold flat, I believe.

The 5-seater uses the (missing) third-row seat space for cargo on two levels, with the open trunk space itself (on top) and a relatively shallow rectangular mid-under-trunk compartment (underneath).

All three seat versions have open trunk space (on top) and a deeper rear-under-trunk compartment (underneath) just inside the rear lift-gate opening. But apparently the 6- and 7-seater under-trunk bin is larger than in a 5-seater?

This rear under-trunk space--specifically for a 5-seater--is what I would like answers for:
  1. What to call it?

    I've seen it described multiple ways. The Tesla “Shop” webpage calls it the “underfloor bin.”

  2. Where to get a good molded floor liner for this space?

    By Tesla’s own admission, the sub-floor of this bin has limited weight capacity. Plus its fabric covering is--just like the upper trunk surface--vulnerable to dirt and abrasion. It would be nice to have a good-quality, waterproof, molded floor lining. But its floor topography is a little complicated. And 5- and 6-/7-seaters varying in dimensions/shape adds another complication.

    Until recently there was at least one source on eBay in China for 5-seater underfloor bin liners. But not today (that I am aware of). There are still 6-/7-seat versions.

  3. Why do under-trunk bin dimensions vary between 5- and 6-/7-seater versions?
If anyone can fill us in on the mysteries of the under-trunk bin, or can suggest
a good source for a floor liner for the 5-seater, please let us know.

Under-Trunk Area - outlines.jpg This is an overhead shot of my 2021 (non-refreshed) rear underfloor bin, with red dashed lines added to emphasize the irregular shapes (to accommodate the rear motor, drive-train, or suspension I assume).

Under-Trunk Area - measurements.jpg Measurements I took (to compare with Asian-source information, hence the use of metric units).

Under-Trunk Measurements from Hong Kong.png Measurements from an eBay source of liners for 6- & 7-seater underfloor bins. Note the greater size. Why would that be?

5-, 6- & 7-seater.jpg Here is a visual comparison adapted from an eBay ad for 5-seater underfloor bin floor liners (no longer available). Note that the surface topography of the bin floors is similar, but different between the 5- and 6-/7-seater bin floors. Tesla could have done us a favor if they 'd made the underfloor bin shapes consistent. What will it be like for the 2021 refreshed cars?
 
Tesla could have done us a favor if they 'd made the underfloor bin shapes consistent.
I’m actually glad that the underfloor bin shape isn’t something they optimized, as it gives me hopes they were optimizing important things about the battery and motor design. That being said, it is a terribly lumpy spot which does seem to have changed over time and with the different seat configurations. For my 2017 7-seater, I first used the non-Frunk part of this mat set. Although it wasn’t meant for the underfloor region, it actually worked ok.
99EFD222-8672-440A-B8DE-4E19B53AC155.jpeg


Then I tried to improve it with this Evannex bin. To its credit, it is flexible and molds to any shape. To its disadvantage, it is flexible and molds to any shape, not doing a whole lot for organizing things.
D5FB4E35-2BCF-44A8-8447-4F6B28003BB8.jpeg


It’s an area that I guess, like you, I thought about when I first got the car. But i realized it has been years since I thought about it and for me, in actual practice, a simple blanket would have sufficed for most any protection.
 
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Yes, I'll probably ignore it eventually too. I figure to put the Gen 2 Mobile Connector, NEMA adapters, and tire repair kit in it, close the cover, and forget it. But I'd still like a molded liner. Not sure why availability from China has suddenly ceased.

Same with the mid-under-trunk bin, which is shallower, but has a flat bottom. What is it good for? Do 5-seater drivers use it? It also has a removable cover (that forms part of the trunk floor). (Your car has third row seats instead of that.)
 
...Then I tried to improve it with this Evannex bin. To its credit, it is flexible and molds to any shape. To its disadvantage, it is flexible and molds to any shape, not doing a whole lot for organizing things.

Since I will probably keep the rear seats folded flat most of the time, I'll have (a) the large flat trunk floor space and (b) the long rectangular space just in front of the rear seats (where passengers' feet would be) to hold permanent and temporary cargo. I was looking at open organizer boxes on Amazon, but a lot of them suffer from complaints similar to yours--cheaply made, too flexible (not supportive, et cetera. I think I'll take trips to Target, Costco, and Home Depot to see what they have for hard (plastic) storage boxes (that can be used with the tops off. Need to get a good brand, so that the plastic does not readily degenerate from heat.
 
Yes, I'll probably ignore it eventually too. I figure to put the Gen 2 Mobile Connector, NEMA adapters, and tire repair kit in it, close the cover, and forget it. But I'd still like a molded liner. Not sure why availability from China has suddenly ceased.

Same with the mid-under-trunk bin, which is shallower, but has a flat bottom. What is it good for? Do 5-seater drivers use it? It also has a removable cover (that forms part of the trunk floor). (Your car has third row seats instead of that.)
I can’t comment on the 5-seater, since ours is a 6-seat model, but I use the undertrunk for exactly what you describe. Mobile Connector, charging adapters, sun shade, tire patch kit & air pump, road safety kit (flares, hand tools, duct tape, etc) and a robust first aid kit. Oh, we also keep reusable shopping bags in there for impromptu stops at the store.

Otherwise, I only use that space for additional items on a road trip. Felt the same in the beginning (wow I’d better get a liner for this!) but ... nah. Not an area that gets much love or attention from us, sadly.
 
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This rear under-trunk space--specifically for a 5-seater--is what I would like answers for:
  1. What to call it?

    I've seen it described multiple ways. The Tesla “Shop” webpage calls it the “underfloor bin.”
Mine is called the bilge. I use the shallow covered space behind the seats in the 5 seater all the time, I make weekly very large Costco runs, it is ideal for cases of canned goods as well as items sensitive to being crushed.
 
Is there anyway to remove the 3rd row with a 7 seater? I ordered a 7 seater but I may only need it twice a year...

I don't know for sure. But based on experience so far from watching mobile service tech and YouTube videos, seemingly everything on a Tesla will disconnect if you know the tricks. That said, seats will have to be securely attached for safety reasons. There will surely be strong bolts torqued down that secure them to frame members.

I had always hoped that Model X rear seats would be removable (like in some SUVs and vans), but that has never happened. Maybe resign yourself to not removing the 3rd row, because:
  • It may be difficult to remove and re-attach easily and safely.
  • Doesn't the third row fold down flat, increasing rear cargo storage?
Sorry this isn't more helpful.