How To Determine Which Sidewinder Will Fit Your Current Pin Box Bolt Pattern

Updated 08/31/2021 | Published 08/30/2021

Question:

There is no part number on the pin box only the VIN number

asked by: Cynthia D

Expert Reply:

Since you don't have the serial number or part number of your fifth wheel's pin box there is another way to determine what you have so that we can find the corresponding sidewinder pin box to replace it.

1. You'll need to determine the style of the pin box you have. If you look at the attached picture below you'll see the different styles of pin boxes.

2. You'll need to measure the horizontal bolt hole distance, vertical bolt hole distance, bolt size, bolt head size, front row of bolts to king pin, back row of bolts to king pin and pin box width. You'll also want to record the number of bolts per side that secure the pin box to the trailer frame. I have attached a diagram showing the measurements needed with labels for each measurement that we'll use in step 3.

3. I've attached a spreadsheet for each style of pin box and we'll go to the style you currently have and find the matching measurements to determine exactly what pin box you have.

Now that you know what pin box you have you can find the corresponding sidewinder. For example, a common pin box on many fifth wheel trailers is the Lippert 1621 which would can be replaced with a 5th Airborne Premium 5th Wheel Air Ride King Pin w/ Sidewinder and Turret - 16,000lbs # RP61422. If you need help finding the correct fit for your pin box then just reply back with what you have and I can find the corresponding sidewinder.

You'll also need a wedge kit to lock the king pin in place in the jaws and prevent it from rotating. These are hitch/pin box specific so you'll need to match up the wedge correctly for it to fit right. I've attached our page of wedge kits but if you need help finding one I just need to know the 5th wheel hitch you're using and the sidewinder pin box.

expert reply by: Kevin C