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Replacement for foam over spare tire

Discussion in 'Prius c Accessories and Modifications' started by CAlbertson, Oct 25, 2012.

  1. CAlbertson

    CAlbertson Member

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    I want to replace the foam used over the spare tire with something that allows storage. That foam is a total waste of space. I'd buy something if it were available but don't see it.

    So my idea is to cut out a pair of 1/4 inch baltic birch plywood panels using the top of the foam blacks as templates. Baltic birch is the best available grade of ply and is very strong. Then I'd need some kind of support under. Has anyone done this yet? The hard part is the support. I'd need to make a "skirt" around the edge of the plywood.
     
  2. JACoH

    JACoH Enjoying the mileage

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    Check out Griot's Garage on line, seems that they have a storage box like thing that might be what you are seeking.
     
  3. CAlbertson

    CAlbertson Member

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    If they have it, I can't find it.

    Maybe I was not clear. Here is what I think I will have to make: If you lift up the carpet in the rear of the Prius C you find two custom blocks of foam. These simply take up space and seem to have no other function except making the carpet flat.

    What I'd like is to replace the foam with a plywood floor so that there would be storage space under the plywood floor. The trick is to not add more weight.
     
  4. BlueStreakinC3inIN

    BlueStreakinC3inIN New Member

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    The only thing I'd suggest you consider is that those foam pieces may provide some shock absorption in an impact. I figure it would not be too much, but just a thought for you to consider. The one and thus far only accident I've seen a Prius Hatch in was major rear end collision. With our C's being shorter, that foam would have been crushed in that one. :)
     
  5. Boatycall

    Boatycall Junior Member

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    I just took them out and left the rug over the tire. Free'd up a very noticeable amount of space.
     
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  6. filipinoof07

    filipinoof07 Junior Member

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    Sounds like a good idea. I wonder if you can shave down that black foam. Does the carpet lay pretty flat over it? I like that the foam keeps the floor flat, but you're right the loss of trunk space is a bummer.
     
  7. PriusCinFL

    PriusCinFL Junior Member

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    I've had my 2012 Prius C just four days and very quickly was surprised that Toyota gave no thought to making good use of the space under the mat in the trunk considering how much effort otherwise went into this car. Especially in light of the fact that the car has very little storage space.

    CAlbertson's idea of using 1/4" plywood as a lid sounds good. I wonder if it came to fruition. Gluing some kind of support around the perimeter of the trunk shouldn't be too difficult. I wonder why the plywood should be cut in the middle. This would weaken it and require extra supports where it was cut.
     
  8. JarOfAlmonds

    JarOfAlmonds Junior Member

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    I actually ended up doing a project to fix this over the summer as I got fed up with my milk crate of stuff taking up precious trunk space. I took a piece of 1/4" MDF and cut it to shape of the carpet mat. I then cut and glued some cheap dollar store rugs to the MDF to pretty it up a bit.

    The supports were the tricky part of the whole thing. I wanted to use edge supports like what was previously mentioned (and like the Yaris), but I found that the side plastic pieces to be too flexible that I didn't trust them to take weight, and then there was the issue of supports for the front (by the seats) and rear (on top of the tire). What I ended up using were four assemblies of galvanized pipe (flange, 5" or 6" nipple, and an end cap) to use as legs, and strategically placed them (two in the back, one on each side) around the perimeter to try and provide the best support without compromising storage capacity. The plan was to use the spare tire as a center and rear support through the use of high density foam. It does end up sitting slightly higher in the trunk in comparison to the original foam pieces by at most 1/2".

    The rest was ease of use additions, such as carpet on the legs to make sliding easier, and a piece of strapping to pull the MDF up easier.

    As a result I can fit the following underneath that was taking up room in my trunk: emergency kit, bicycle pump, bottle of windex, roll of paper towel, gloves, window brush and squeegee, and reusable shopping bags with tons of room remaining.

    The only concern is that it is a tight fit and if I ever get around to installing rear seat covers I may need to trim the back edge to accommodate the extra thickness of the seats.

    I'll try and take pictures when I can, as they'll be better than my description.
     
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  9. c4

    c4 Active Member

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    I had the same idea.. There's actually a huge amount of space in the well around the spare tire that could be used, but is completely wasted by those foam inserts.. The one big Wth? decision by Toyota that I really question is why they didn't make a space for the jack in the rear compartment vs. storing it under the driver's seat?? They keep the lug wrench and jack handle in a little toolkit with the spare tire, but why not the jack as well?? What purpose does it serve to store the jack under the seat

    I'm not done, so no pictures yet, but in my case, I've started by getting a length of 1/2" galvanized steel conduit and using the carpet as a rough guide for shape, I've bent the conduit into a shape that fits closely around the edge of the well. I've then riveted some aluminum tubing across this rim for strength and rigidity and support of whatever eventual surface I will put on there, and then I've got a bunch of wooden legs screwed in through the conduit and some of the tubing to support this frame around the edges and centre. The next step is to either get some punched or expanded aluminum grating or perhaps just plywood, to attach to the top to make a platform for the original carpet to go back on, and I'll probably attach it with a strip of piano hinge or something so I'll have hidden storage below and conventional storage above.. It will be nice to be able to keep a small toolkit, a bottle of oil, a can of tire sealant and other essentials in the car without taking up precious "trunk space"..

    I'm thinking however, that the surfaces of well itself should probably be protected by something vs. just letting everything sit on the bare paint.. If nothing else, then to prevent the contents from sliding around and rattling while you drive.. My initial thought is to get a roll of the cheap "replacement headliner" from the parts store.. Next question though is: glue it down or just leave it floating? What's the consensus?
     
  10. xliderider

    xliderider Senior Member

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    Galvanized pipe and flanges are pretty heavy though. PVC pipe would be much lighter. Hollow PVC pipe might be susceptible to vibration and buzzing though, so once everything is setup, perhaps fill the PVC pipe with some of that expanding foam sealer in a spray can?

    Again, PVC pipe for legs?

    Maybe apply some type of spray on undercoating, or "rubber in a can" type thing? Some people have sprayed on PlastiDip in the hatchback tire well for sound/vibration dampening.
     
  11. JarOfAlmonds

    JarOfAlmonds Junior Member

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    I don't find my legs that heavy as they are only around 5/8", however PVC pipe for legs would definitely be lighter in comparison. I looked at using PVC legs, but my issue was being able to source smaller size PVC (<3") where I live without ordering online, especially the fittings, but the galvanized pipe was readily available to me and cheaper. I'm also one of those people who sometimes equate weight with sturdiness. (To which I must be a very sturdy man. Ha!)

    I like your idea of expanding foam in the PVC pipe, where if nothing else will provide a bit more structural integrity, my main concern with vibration and buzzing would be where the legs contact the car's structure without something like a thin piece of carpet or foam to remove the PVC on metal contact. (Assuming you're placing the legs on the bare metal in the spare tire well)
     
  12. xliderider

    xliderider Senior Member

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    Something like these on the ends to cushion the ends would work:

     
  13. JarOfAlmonds

    JarOfAlmonds Junior Member

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    That is a brilliant idea! I can't believe I didn't think of those... I'm definitely going to pick some of those up on my way home to try. Hopefully I can get rid of the carpet + rubber band solution I'm currently using. :D
     
  14. Fauxknight

    Fauxknight Active Member

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    Probably with a foam cutter/hot knife it'd trim down just fine. I don't think it's necessary though, just stow the foam somewhere (like wherever you've put the rear headrests and OEM mats) and build a completely separate cover for it.

    The underused space over the spare was one of the few disappointments I've had with the vehicle. My only guess on the foam would be to insulate sound in that area? When the weather is warmer and I get some access to tools (not much here at the condo) I'll likely look into doing this myself, as well as maybe making a more permanent lower grill cover. Currently I'm using a large toolbox to hold my emergency supplies in the trunk, but with my job I frequently have to remove it to make room for my next run.
     
  15. JarOfAlmonds

    JarOfAlmonds Junior Member

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    I think the poor engineering of the spare wheel well space is a major disappointment for a lot of Prius C owners. I was especially disappointed when I looked at a new Yaris after the fact that looked to have very similar internal side panels to the Prius C, except it had a ledge for a proper cover and provided a significant of space in the spare wheel well. Oh well. :(

    When I was planning how to do my replacement cover, I had the foam out of the car for about a week. In my experience I didn't experience any noticeable change in sound volume or the type of sound. This included traveling on both tarmac and gravel roads. Of course YMMV, I would suggest doing your own testing if you're able to live without a functioning trunk for a few days.

    There is the second theory that the foam is to help protect the HV battery in the event of a rear crash. However I believe if that was the case Toyota should have put something in the owners manual saying to keep the foam in the spare wheel well for such an event, as there is still plenty of car between the rear bumper and the battery pack. Best I can figure, the foam was just Toyota shaving a few dollars off the price, and those of us that use our little car as more of a utility vehicle have to jury rig a solution to squeeze out a bit more storage space.
     
  16. gbouten

    gbouten Junior Member

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    After blowing out a tire while on vacation I now have a real tire and rim. I took out the foam and am in the process of making a cover that fits over the tire as it is a bit thicker than the donut tire. Let ya know when I'm done.
     
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  17. B2FiNiTY

    B2FiNiTY Active Member

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    can't wait to see it!
     
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  18. c4

    c4 Active Member

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    Finally finished my trunk foam replacement.. Ended up being, as I mentioned in my last post, a length of 1/2" EMT electrical conduit bent by eye to roughly match the shape of the trunk well- so a rough D shape, straight on three sides and curved along the edge facing the rear of the car.

    The conduit has four legs that hold it up off the bottom of the well at the same level as the original foam forms. The two rear legs are 5-1/4" long and the two front side legs are 4-1/2" long. The top surface of each leg is concave to fit right along the conduit and prevent twisting, and the legs are fastened to the conduit by simply drilling a hole through the conduit and driving a 3" wood screw through the hole and into the leg, which is pre-drilled to prevent splitting.

    Two square aluminum tubes were placed in a V shape, and fastened to the conduit frame by gluing in a square dowel in the tube and like the legs above, simply drilling a hole through the conduit at an angle and driving a wood screw through the hole and into the dowel. In this case, the dowels were not drilled as any splitting would only serve to lock the dowel inside the square tube more tightly. The reason for the V shape was to clear the top edge of the spare tire while providing additional rigidity to the conduit and acting as a platform for the lid to sit on.

    The lid was perforated aluminum plate, 1/16th inch thick, 1/8" smaller on all edges than the carpet. The reason for the size reduction was to accommodate application of door edging all around the lid to prevent scratches on the plastic around the well and the back of the rear seats.. I was going to cut the lid in two and put in hinges so I'd have left and right compartments, but the lid as a whole worked just fine and I just left it all in one piece and didn't bother with hinges.

    The end result looks indistinguishable from the foam forms when the carpet is in place, but gives me a huge amount of hidden extra storage. The new shelf does not bounce, vibrate or make any noise, the removal of the foam has not increased or changed the cabin noise and the platform has has no problem supporting over 200 lb of feed bags without bending or warping..
     

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  19. DadofHedgehog

    DadofHedgehog Active Member

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    My 1990 BMW 318i had a wonderful donut-sized 1.5 liter steel gas can that fit right inside the full-size spare tire. the BMW died at 199k miles, but I still have the donut gas can which has saved my bacon many times. Such a donut gas can can potentially provide support for a "deck" and I'm sure they can be found in the aftermarket.
     
  20. fourenty

    fourenty Junior Member

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    c4, great job! Thanks for the inspiration to "fix" my C storage problem.