Community Forums

tampabiker · 11-24-2015, 09:50 PM

Hello, all

I have a 2014 DRV Mobile Suites trailer with a Mor/ryde pin box on it. Has anyone had this and changed out to a Lippert Flex Air pin box? What would you say are the advantages/disadvantages of such a change? The Flex Air looks like it would absorb more shock, but I don't know that. What do ya'll think? Thanks for any help on this.

paz · 11-25-2015, 07:59 AM

I ordered a Flex Air on our DRV Tradition, and I wish I didn't. I don't know how the ride with the Flex Air compares to the Mor/ryde, but IMO the ride with the Flex Air on rough roads isn't all that great.

For me, a big problem with the Flex Air is the top part is horizontal to allow space for the air bag rather than tapering down like the Mor/ryde and most other pin boxes. The way DRV builds its 5th wheels, there is very little space between the bottom of the overhang and the top of the Flex Air pin box where the air valve is located. It is almost impossible to get any type of air chuck on the valve of the Flex Air, and there isn't even room for a 90º valve extension. To make matters worse, the air bag looses pressure and I need to add air frequently. I would stick with the Mor/ryde.

Cummins12V98 · 11-25-2015, 10:15 AM

The FlexAire is ONLY rated for 18K. Not enough for MOST DRV's. They still sell the TrailAire kingpin, supposedly they have discontinued the TriGlide portion.

The TrailAire kingpin works great! You can see the RV floating in the rear view mirror. To fix the air loss fill the bag to 100psi when not hitched, let it sit for 24 hours that should fix the slow leak.

Yes the air valve is not EASY to get to but with the mod I made is it no problem airing.

jimcumminsw · 11-25-2015, 01:33 PM

The Mor/Ryde pin box only works in one plane where the Flex air pin box works in three planes of motion. The Flex Air in my humble opinion will provide a better ride to the tow vehicle and trailer do to the three planes of motion.

This is my second 5er with the Trail Air Pin Box which only has two planes of motion which control up and down and some fore aft control do to the shock absorber. I have been extremely happy with the Trail Air pin box for my needs. We have towed all over the US with both trailers putting on close to 15,000 miles on them.

Jim

paz · 11-26-2015, 11:06 AM

Quote:

Originally Posted by jimcumminsw

The Mor/Ryde pin box only works in one plane where the Flex air pin box works in three planes of motion. The Flex Air in my humble opinion will provide a better ride to the tow vehicle and trailer do to the three planes of motion...

Jim

Please explain "3 planes of motion" for the Flex Air. I only see 2 degrees of motion (not necessarily in 2 different planes) - up and down from the air bag (the shock absorber dampens the up and down motion, but I can't see how it allows movement in any other direction) and a rocking motion (also up and down) from the plate on the bottom. There is a rubber pad on the bottom plate, but that seems like it only helps absorb shock and doesn't allow motion left and right or fore and aft like the rubber pads on the MOR/ryde.

grashley · 11-26-2015, 04:26 PM

The three planes of motion, from basic Geometry are these:
Lay a yardstick across the hitch, across the pickup box. Raise and lower one end. This represents one plane.
Repeat this exercise with the yardstick laid from the cab towards the tailgate. This represents one plane.
Stand the yardstick on end, aimed straight up at the sky. This is the third plane an RARELY comes into play. Gravity holds the 5er down 99.9% of the time, and the hitch prevents this movement the rest of the time.

paz · 11-27-2015, 08:23 AM

Quote:

Originally Posted by grashley

The three planes of motion, from basic Geometry are these:
Lay a yardstick across the hitch, across the pickup box. Raise and lower one end. This represents one plane.
Repeat this exercise with the yardstick laid from the cab towards the tailgate. This represents one plane.
Stand the yardstick on end, aimed straight up at the sky. This is the third plane an RARELY comes into play. Gravity holds the 5er down 99.9% of the time, and the hitch prevents this movement the rest of the time.

I understand geometry. I would call the hitch itself a plane (defined as a flat surface) and I would say it could move in 3 dimensions - left & right, fore & aft and up & down; but that's just a matter of terminology.

However, the question that remains for Jim is how the Trail Air moves in 3 planes or dimensions, whatever you want to call them.

schrod · 11-27-2015, 01:40 PM

I can only visualize it moving in two directions. Fore and aft and up and down. Moving sideways would be detrimental to towing.

Cummins12V98 · 11-28-2015, 09:23 AM

Up N down, fore N aft is all I see.

dougandrobin · 11-28-2015, 05:01 PM

Add an Air Safe hitch and you have all the planes covered 😀

Dale & Mark Bruss · 11-28-2015, 05:21 PM

Ditto on the Air Safe Hitch.

One problem with air pins is that they all extend the pin forward putting a rotational stress on the pin box.If you have a lot of margin on your pin box that maybe okay but many of the heavier trailers (like DRV) are near the limits for the pin box.

Air pins only have an up/down motion. The MOR/ryde rubber pin only has for/aft buffering.

paz · 11-29-2015, 04:04 AM

Quote:

Originally Posted by Cummins12V98

Up N down, fore N aft is all I see.

I don't even see fore and aft because the pivot at the back of the bottom plate only allows the bottom plate to pivot up and down. By the way, you show a Trail Air, and Jim was talking about the Flex Air moving in 3 planes. As far as I can tell, the Flex Air has another pivoting plate where the pin itself is located, and it looks to me like that only pivots up and down as well.

Cummins12V98 · 11-29-2015, 10:21 AM

Quote:

Originally Posted by paz

I don't even see fore and aft because the pivot at the back of the bottom plate only allows the bottom plate to pivot up and down. By the way, you show a Trail Air, and Jim was talking about the Flex Air moving in 3 planes. As far as I can tell, the Flex Air has another pivoting plate where the pin itself is located, and it looks to me like that only pivots up and down as well.

I understand the question but the hitch I am showing acts exactly the same as the FlexAire. See the bottom plate and the three grease Zerks that portion slides fore and aft. They make the same kingpin without that option and it then is an up n down motion only.

paz · 11-30-2015, 06:13 AM

Quote:

Originally Posted by Cummins12V98

I understand the question but the hitch I am showing acts exactly the same as the FlexAire. See the bottom plate and the three grease Zerks that portion slides fore and aft. They make the same kingpin without that option and it then is an up n down motion only.

OK, that explains it. I couldn't tell from the photo that the bottom plate slides or that the round projections on the bottom had zerks. At first, I thought the projections were socket head cap screws just holding the bottom plate in place. Thanks for the explanation.

By the way, I have a Trail Air pin box. The bottom plate on mine does not slide, which was another source of my confusion..