Best Pin Box Upgrade Recommendation for 2017 Grand Design Momentum with a 1621 Pin Box

Published 01/10/2019

Products Featured in This Question

Curt Air Ride 5th Wheel Pin Box - Lippert 1621 & 1621HD - 21,000 lbs

(88)

$1384.99

Trailair Flex Air 5th Wheel Pin Box - Lippert 0719 - 18,000 lbs

(2)

$1456.38

Curt Flex Air 5th Wheel Pin Box - Lippert 1621 - 18,000 lbs

(192)

$1667.90

Curt Flex Air 5th Wheel Pin Box - Lippert 1621 - 21,000 lbs

(192)

$1727.80

Question:

Follow up on a previously asked question. My 2017 Grand Design 350M fifth wheel when loaded is 15,500 to 16,000 lbs. your suggestion was to replace the LC 1621 standard pin box with LC Flex air 328492 rated for 18,000 lbs. My question now is, would the LC FLexair 369535 rated for 21,000 lbs be of any advantage or would this be over kill. I understand it is a couple of hundred dollars more but wondering if the extra weight rating would be any advantage, such as Added safety factor or would this affect the ride improvement that I am looking for.

asked by: Mark R

Helpful Expert Reply:

For your 2017 Grand Design Momentum that has a Lippert 1621 pin box the best upgrade we have is the Trailair Flexair part # LC328492. This has cushioning vertically and a pivoting king pin plate that allows for cushioning front to back as well. This will give you a noticeable smoother ride quality than what you currently have.

expert reply by: Jameson C

Mark R.

10/22/2018

You recommended the flex air #328492. If I have long bed trk with B and W companion hitch is that the right one or is it the # 328484

Jameson C.

10/22/2018

The pin box you just mentioned # LC328484 would not work for you as this fits as a replacement for the Lippert 0719 and what you have is the 1621 on your trailer. The pin boxes are made to specifically fit trailer frames and you have to go with the matching pin box for the trailer. This means you'd have to go with the # LC328492 that I mentioned earlier.

Mark R.

1/10/2019

Jameson C.

1/10/2019

The capacities of the pin boxes are rated conservatively which means as long as you are under the capacity of the pin box you are very safe. If you wanted to go with the higher rated # LC369535 you certainly could and it would perform well, but I don't believe you'd ever find yourself in a situation with the lower rated Flex Air wishing you had more capacity.