Sprinter Bed / Flarespace Install - Rivnuts okay?


New member
Greetings all,

I'm posting this after the fact which is obviously too late. I installed a bed kit in my sprinter yesterday and as soon as I have it in, I got second thoughts about my method.

Essentially, I used two riv nuts (5/16) at the end of each rail, though the pillars around the corresponding window in the rear. I did this much in the same way that CWAR did this in 2017 with the same kit. (https://sprinter-source.com/forums/index.php?threads/56107/) The rails are mounted 40" off of the floor to accommodate a bike and there are flares to accommodate sleeping sideways. Now I'm concerned that these rivnuts won't hold and it's too late. Yes, I should have used plus nuts, but to be brutally honest, I didn't know there was a difference between the two until I had my first few in.

Questions: Is this sufficient for two people? If not, what can I do?

I can't put plus nuts along the bed rail as it sits too high. I have read somewhere that plus nuts are fine. Too late for that, sad to say. I've also read that it's best to weld a supporting plate -but I dunno how to weld. How screwed am I?
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Aqua Puttana

Poly - Thread Finder
Essentially, I used two riv nuts at the end of each rail, though the pillars around the corresponding window in the rear. ...

How screwed am I?
You don't say what size fasteners.

If that is 8 ea. 1/4-20 bolts it is plenty strong.

Properly installed Rivnuts are strong.

One caveat is that the stresses remain basically in shear and there aren't any excessive pullout stresses. The van body will twist a bit as you ramble down the highway. The ledger pieces will be fine. It is best that there is some design to allow some give on the cross supports as the body flexes.

That said, too rigid of cross supports is a pet thing of mine. There may automatically be enough give in the assembly.

If you are still concerned you could consider adding 1 ea. 3/16" steel pop rivet to each 2 bolt end.

:2cents: vic


New member
Thanks for your reply and insight. You're right, I did not include the fastener size which is 5/16-18. I have since updated the original post. I have two rivnuts at the end of each rail for a total of four riv nuts per rail. (8 for the entire bed) I was concerned about pull out stress, but perhaps I'm being overly paranoid. I wish I had used plus nuts.

I *did* think of twisting and motion in the van and there is about 1" on each side of the bed frame to the van bulkhead to allow for that. (I too share this pet thing and I see too many people building very rigid structures without considering how the vehicle will move.)

Thanks again!

Aqua Puttana

Poly - Thread Finder
5/16-18 x 8 ea. is even better. I believe that the MOAB commercial design uses one 3/8" fastener per corner.



New member
Thank you all for your helpful replies! I gave it a test run one night this weekend. With two of us on it ~180 / ~120 lbs (one a fitful sleeper), it held up just fine. I saw no damages or any indication there was metal deformation around the riv nut. My anxiety is assuaged, but in the future, I will use plus nuts.

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