Fifth wheel hitch follow-up

Back in June I posted <a href="http://www.yesterdaystractors.com/cgi-bin/viewit.cgi?bd=ttalk&th=1829366">a question on fifth-wheel hitches</a>; I was trying to figure out what the optimum height is for a hitch so I could select the right combination of components. I was thinking the nominal height should be about 48 inches above the ground, allowing a couple of inches of sag. So about 50 inches off the ground, which worked out to 16 inches above my truck bed. The combination of components I wanted to use added up to (I thought) 17-1/2 inches. Here's how it turned out.

Reading the specs on etrailer dot com, I thought the combination of the Curt A16 head, slider, and GM puck mount adapter was going to have a minimum height of 17-1/2 inches. I thought that was close enough, so I opted for the A16 head instead of the shorter and cheaper E16. But when I got everthing installed, I was shocked to find the real hitch height was over 19 inches! The specs didn't include the height of the puck mount adapter, which is about an inch and a half. I thought about sending back the A16 head and exchanging it for the E16, but the E16 is a much poorer design than the A16.

Once we finally found a trailer we liked, we hitched it up and saw that it was about four inches too high. I had the dealer raise the pin box to its highest adjustment, which dropped the trailer two inches. I then modified the hitch head by cutting an inch off its skirt. This allowed me to lower it an inch, at the cost of removing the highest adjustment. (I'm sure Curt would not approve of this modification, but I don't believe it affects the integrity of the hitch.) So the trailer now sits about six inches above the truck bed sidewalls, which is enough to allow for plenty of movement. The trailer is still about three inches higher in front than in the rear, but we can live with that.

The interesting thing I discovered is that I really don't need the slider with my trailer. The nose of the trailer is curved, which allows it to turn sixty degrees or more without hitting anything. A slider is still needed to get a full ninety degrees, but do you ever really need to do that? A little planning and you shouldn't find yourself in a bind. Using the fixed puck-mount legs instead of the slider and puck adapter would have lowered the hitch several inches.

FWIW, 48 inches does seem to be the nominal pin height for a fifth wheel travel trailer, at least for the "half-ton towable" ones. It seems to me trailer manufacturers need to make this a bit higher, given that half-ton pickups are getting really tall these days. And three-quarter ton trucks like mine seem to run a couple inches taller than half-tons.

If trailer is not level it puts undue strain on one axle not good

Good post Mark,some handy information. After mounting a slider in my truck I found that fore and aft position is not near as critical as it's made out to be. To hear some tell it,if pin isn't within 3/4trs" of recommended position you'll lose the trailer before 10 miles down the road. I can't tell one bit of difference in ride and control when hitch is slid back.

Well I have never pulled a fifth wheel type trailer with a pickup truck. I use a gooseneck type just about every day. I turn 90 degree plus regularly getting around in barn yards. So only turning 60 degrees would be a real pain for me. I think you may find it that way too when you in city driving. IF your trailer is very long you will find just getting around some streets, with traffic setting at intersections, will require tighter turns.

I cringe when I see these guys pulling BIG campers with a half ton pickup. They can go but stopping is questionable.

As for the front being 3 inches high. IF you pull it much you will wear the back tires out faster even with the equalizer working. IF your like most camper guys you will not pull it near as much as you think. So the height will not make much difference.

I have been selling and installing all kinds and brands of hitches for close to 40 years. I used to work part time for an RV dealer. I have never run into but one trailer that I couldn't take care of with the adjustment in the trailer pin box and the hitch.It was an older RV and an new 4WD Ford 350 Dually. We put a dexter axle lift kit under the axles on the camper and raised it up approx. 3 inches. Took care of the problem. The new RV manufacturers are building trailers now to compensate for the higher bedsides on the new trucks. I had customer that had a receiver style hitch and a 28 ft camper. The ball height was 4 inches too high, but he wouldn't let me cut the head and lower it down to where it needed to be. He made one trip and wore out a set of tires on the rear axle.When he got back he was glad to let me fix the head.

> We put a dexter axle lift kit under the axles on the camper and raised it up approx. 3 inches.

W-M, is that "lift kit" the so-called <a href="https://www.etrailer.com/Accessories-and-Parts/Dexter-Axle/K71-385-00.html">"over-under" kit</a> that moves the springs from below the axles to above? If so, that won't help because my springs are already above the axles.

I've considered adding a small spacer, less than one inch thick between the axles and springs. Lifting the springs an inch would have the same effect as lowering the hitch two inches. But I understand that can cause problems with spring wrap when braking.

Mea culpa, I realized that raising the springs an inch is the same as lowering the hitch one inch. Which is still enough to level the trailer out.

> I use a gooseneck type just about every day.

I've noticed that once you get west of Iowa, almost all the travel trailers parked in peoples' yards have gooseneck adapters. I assume they don't want to have to keep removing and replacing a fifth wheel hitch anytime they switch trailers.

> So only turning 60 degrees would be a real pain for me. I think you may find it that way too when you in city driving.

I haven't done the math, but I think the max angle is around 70-80 degrees. Of course, the slider allows jackknifing beyond 90 degrees. But the slider won't help when maneuvering in city traffic, as you have to get out and unlock it when you need to slide the hitch back. There are some setups that automatically handle sharp turns: the automatic sliders by Demco and Pullrite move the hitch back when turning. And the Revolution or Sidewinder pin boxes by Reese move the pivot point from the hitch to the trailer end of the pin box.

Do not put anything under the springs as that will make it even more likely to have problems with springs and alignment. I really don't think 4" out of level is going to be an issue. Just look at what is going down the road around you and you will see that 4" out of level on a trailer that long is no big deal. I've never seen that cause tire wear problems. Any tire wear issues I've seen have always been traceable back to alignment issues.

If you really want to make it level and there is nothing left in the hitch, the best way would be to find taller suspension parts if possible. If what you have is already the tallest, and that may well be, then cut the suspension off the main beams and add a 4" channel or tube spacer there. That will keep your suspension geometry correct.

> Do not put anything under the springs as that will make it even more likely to have problems with springs and alignment. I really don't think 4" out of level is going to be an issue.

Thanks Jon. It's only 3" off front to rear, which I think is acceptable. I can see the difference because I know it's there; I don't know that anyone else would notice.