King Pin to Bolt Hole Rows on Lippert Flex Air Pin Box for 1621 5th Trailer Pin Boxes

Question:

You give detailed measurements for the 0719 version of the Trailair Flex in the video, but not this 1621 version..... These two are physically interchangeable with differences 9inch in length for the fixed pin versions. What are the kingpin to first row/second row of bolts dimensions for this 1621 box? I need these to decide which one to order.

asked by: Tony H

Helpful Expert Reply:

The pin box used on a 5th wheel trailer is chosen based on several factors. If you used a pin box that is too much longer than what it was built with it could put too much stress on the frame. On the Lippert 1621 the center of king pin to front row of bolt holes is approximately 17-3/4 inches and to the back row approximately 25-5/8 inches. The aftermarket box # LC328492 will be approximately 3 inches longer which would be fine.

expert reply by: Michael H