Fifth Wheel Hitch- Above Bed Rails (ISR) or Below Bed Rails

If you want to tow a fifth wheel one of the questions that you will need to answer is what kind of fifth wheel rails would you like to have in your truck. There are basically two styles of fifth wheel hitch rails.

  • Above Bed Rails – typically called Industry Standard Rails (ISR) for short
  • Below Bed Rails- there are many types of hitch that fit in this category as well.

We will talk about these different type of fifth wheel hitch rails, their advantages and disadvantages and try to help you decide which type may be fore you.

First things first

You may have a newer pick-up truck that came with a fifth wheel prep package. If this is you, you are good to go! Just make sure you purchase a Fifth Wheel hitch that mounts to your fifth wheel prep package.

For the rest of us

There are still hundreds of thousands of pick up trucks that do not have any sort of provision to haul a fifth wheel. For you there are the two choices. Above Bed or below bed fifth wheel rails.

Why do I need rails?

That is actually a really good question. Most people think that all you need is to purchase the Fifth Wheel hitch to be able to pull a Fifth Wheel trailer. While this is partially correct you have to thing about the entire system that is used together to safely tow your fifth wheel.

Your Fifth Wheel Hitch System

There are three major components to your fifth wheel hitch set up

  • A Sturdy Truck
    • You need a truck that is capable of hauling your fifth wheel. See my article on How Big of a Truck Do I need to help you determine what size truck you need
  • A Fifth Wheel Rail System
    • This is the purpose of this article- what kind of rails do you want?
    • These rails are what your fifth wheel hitch will attach to.
    • Rails allow your fifth wheel hitch to be removed from your truck so that you can have your bed back whenever you are not hauling your big fifth wheel around.
  • A Fifth Wheel Hitch
    • This hitch will attach to your fifth wheel rails and will be what actually attaches to your fifth wheel trailer.

Which Fifth Wheel Rail System is Right for You?

The reality is that both the above bed and the below bed rail system are fully capable of doing the job.

Both hitches allow you to pull either Fifth Wheel trailers or gooseneck trailer depending on your needs.

The real issue is your personal preference. Some people like having a totally flat bed floor when the fifth wheel hitch is out of the truck, for others having the rails on top of the floor are no big deal.

Here are the pro’s and Cons of both

Above Bed Rails

For above bed rails, like this universal kit from Reese Towpower provide a robust foundation for your hitch.


  • Lower cost
  • Can have easier installation with the use of truck specific mounting brackets
  • Can be used as extra tie off points for when you are hauling things such as your motorcycle or furniture in your bed. (not when you are towing your fifth wheel)


  • Some people find them ugly
  • They can make loading large and heavy objects into your bed a challenge if you would normally just slide the object into the bed. You will have to lift the object over the rails.
  • Can have a lower tow rating than under-bed hitch systems. (20-25,000 lbs)

Below Bed Rails

Below bed rails can range from many products. Some people will use a gooseneck hitch such as a B&W Turnover Ball Gooseneck and use it in conjunction with a B&W Companion hitch leaving them a fully unobstructed bed when the hitch is out.


  • The flat and level bed
  • Aesthetically more pleasing
  • Typically carry a higher tow rating


  • Cost can be much higher
  • Some hitches requiring you to reach into a wheel well to secure the hitch

Wrapping up

As you can see, there are two major choices when it comes to Fifth Wheel rails. You can go under your bed or on top of your bed floor. The choice is really yours and it comes down to cost and personal preference. No two situations are exactly alike so go out and choose the best one for your situation.

Happy towing everyone!