RV Construction Methods – Pin Box

Finally finished up my research on pin boxes. This is the part of a fifth wheel trailer that hooks on the hitch in the back of the truck. Obviously a very important part.  While researching I discovered if you buy a rig and later replace the pin it could cost between $600 and $1,300 plus installation to trade it out. The research is geared towards heaver trailers at 16,000 pounds or more in gross weight.

Pin circled in red

Pin box circled in red

If you are interested in the research I’ve added it to the Foundation and Structure page of this blog. I would really appreciate knowing what pin box you decided on using. And if you have time, also what hitch you have with the pin.

If I’m understanding this right, there are actually three decisions to make here. What pin box, what fifth wheel hitch and what suspension system. I’m researching the other two components and will report on them later.

For now I decided on the following choices:

1st Place RibbonMy first choice is the MoRryde pin matched to the appropriate hitch and suspension system. I’m still studying hitches but am leaning towards having an air bag on the hitch with the MoRryde pin.

2nd Place RibbonMy second choice is the newer Trailair – Flex Air pin.  Again, the pin would be matched with the appropriate suspension and hitch. My decision could change if the Flex Air is limited to an 18,000 pound capacity. Not sure on that.

3rd Place RibbonThe Trailair – Air Ride is my third choice. We may be buying a used rig so I want to keep the option open to using what comes with the rig.



Flex Air by Lippert

Trailair – Flex Air (by Lippert)

Trailair Air Ride

Trailair – Air Ride (by Lippert)


(Update January 2016) While at the most recent RV show a dealership owner told me he brings trailers in with cheaper pins boxes because people are going to change them out anyway. So I’m no longer judging the trailer by the pin it comes with.)


4 thoughts on “RV Construction Methods – Pin Box

  1. Hi Mark, From one Missouri boy to another I’ll throw my two cents in here as it looks like you’re inviting different perspectives on the topic of pin boxes and hitches. I too am in the research phase. My interests are in the full time category, so I’m looking at heavier units than weekender and vacation fivers. There is an air hitch called ET Hitch and it is on the robust side for higher pin and towing weights. Those following your site might want to take a look if they’re interested in another option. ethitch.com
    Enjoy your write ups too – probably a number of us out here getting some good info from your research.
    Thanks, John

    Liked by 1 person

  2. John,

    Yes I’m inviting feedback. That’s the #1 reason I started the blog. Figured I could learn a lot from others. I will take a look at the ET Hitch, appreciate the lead.

    One thing all the research is helping with is as I look at various fifth wheels I’m finding things the dealer may not want to talk about. I used an example once where at the local RV show very few of the “fulltime” fifth wheels had double pane windows. Suppose that is one way they kept the prices down. I’ve never asked why they have lower-end stock pin boxes. Not sure if the dealers leave them on knowing they will be replaced with the customer’s option or if that’s another way to keep the sticker price down.

    Hopefully we all will not be one of those that learns the hard way which is after purchase.


    • Well Mark that’s a good point that I need to note. The dual pane windows I mean.One other item on the ET Hitch – you can look in YouTube for it as well.Gregg of RVHaulers.ca did a video with the inventor Henry Szmyt. And Gregg is very knowledgeable in the Heavy Duty Trucks some full timers have converted.Talk to you down the road,Oh, I’m in O’Fallon; where are you ? John Green


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