Looks like this is a pretty wideranging discussion board for puling stuff. As it happens I am considering a CTD Dodge but right now I'm trying to figure out how much clearance you need between the bottom of the 5th wheel beam and the top of the truck tail.

Whatever I get, the 5th wheel is going into a dump body. It would of course be a short walled "Mason's dump, but the gate posts at the back are significantly higher than the sides.

I've considered some approaches to modifying the gate mechanism to lower them. Little bit of work but I think doable in theory.

On the other hand I find I can get some trailers with about 71" or almost 6 ft. clearance from the ground. That would be about 4.5" over the existing posts on a dodge 3500 cab and chassis with typical Mason's dump.

I've got just about 40" of overhang from the axle to the tail of the truck (that is pretty standard with the 8' dumps) that means you could have the truck pointing down hill at an angle 6 deg. steeper than the trailer and still swing over.

I figure that is tight but maybe doable. Any idea on what the 'standard' allowance for clearance at the truck tail is and/or pointers to forums where they hash out truck/trailer design and compatibility in that area.

Thanks.

Brian

 

5 1/2 - 6 inches I think 4 1/2 is too close. My new trailer pin box was set up with about 4 1/2 inch clearance and I got convinced it would be OK,then when I pulled out of the yard where it was stored it just touched as I turned left. It made a small scratch in an arc about a foot and a half long. When I got home I readjusted to now 5 1/2 inches which is where I have always ran at in the past.

 

Did the samething.. I had 15" rims on my fver and it was causing a slight slant on the trailer and leaving only about 4 1/2 inches of clearance on the tailegate.. I had to change out the rims to 16" which helped alot.

 

I can't figure why 5th wheel dealers aren't more up on that measurement and approach. Maybe there aren't too many people who pull with higher-sided trucks so it is mostly a question of adjusting the hitch and maybe the trailer tires.

But trailer manufacturers do make models that deliberately raise the bottom of the 5th wheel extension. I don't know if there is a name for this feature. You pretty much have to just set the trailer flat and measure.

I've had a couple flat beds with self contained 5th wheel as part of the bed but I've never mounted one myself.

While I was calculating the possible interference of the tail of the truck with the trailer, I noticed a couple threads that suggest the ball be mounted a couple inches forward of the axle.

I had offhand assumed that you would mount it over the axle. I can see going a little forward gives you even a little more gooseneck weight on the truck although the further forward you go the more tail interference and the more crowd when turning.

Any thoughts on the merits of ball placement or results you have experienced with driving differently placed hitches.

Thanks.

Brian

 

A few inches in front of the axle is supposed to put the weight directly on the axle in real world weight transfer.

 

I wouldn't go less than 6" of clearance. I'm right at 6" and the trailer has kissed the top of the bed rails on more than one occasion.

I've got 16" wheels for the trailer coming,that'll give me another 1/2" or so clearance.

 

I have always mounted my hitches directly over the rear axle. My thoughts on this was... I could always move it closer to the cab but why increase the risk contacting the cab with the 5ver in a tight turn? Then I bought our latest 5ver last fall (a Titanium) and the lower front of the trailer is so close to the tailgate I think if the hitch was moved forward more than an inch the tailgate would contact the front of the trailer when hooking up. I just removed my tailgate yesterday and have a net style on now until I can come up with something different.

 

My reese 16k is mounted directly over the axle. At 1.2-1.5k of pin weight it seems to overload my 2500's springs if level is the target. 95-98 gals of diesel in the front of the bed "L" tank levels the truck and makes for a better tow. The truck is a long bed with a full size UWS tool box. I'll solve my problem with airbags, not a weight issue, just distribution.

I think most of the problems we experience are not weight related, distribution is the real problem.

 

My truck's a 4X4 quad cab Long box and weighs in at 7400Lbs with hitch toolbox and 2 people. GVW is 8800lbs that only leaves 1400lbs. Most 5ver RV's have pin weights heavier than 1400lbs. That 95-98 galls of diesel up front comes in around 750lbs (depending on SG) without the tank.

 

and I appreciate it.

As best I can tell from axle ratings, the 3500 duallys (looking in 2nd gen on either side of the 12/24V threshold, e.g. 95-02 I'm looking at are around 14,000 GVW.

But I don't know what the tare is, so I don't know the net load I can add.

I see that GCVW is supposedly 26,000 although I talked to people who actually pull 20,000 so I think they must be going over that a bit.

So it seems the length of the tail is important to where you mount the hitch as well as the real world attempt to get the weight to the axle. The trucks I've been looking at are about 40" from the axle to the tail. So If I put ball a couple inches forward of the axle we're talking 42" and then it is going to more to the corner.

At the corners the beds are about 84" wide, so what we have is an isosceles right triangle 42" sides and the hypotenuse, e.g. the distance from the hitch ball to the corner would be the square root of 2 times 42 squared or a fraction under 60".

What is the normal/standard distance from the hitch to the vertical on the trailer?

 

I don't know if there is a standard for that. I have towed trailers that had 18" of room with the tail gate down, and others that made you wonder if you would have to put up the gate just to get it hitched. You might have to find a trailer dealer and take a few measurements of different models. Seems like the newer trailers have more clearance.

I usually place the ball 3" ahead of center on long bed single wheel trucks and duallys. However on extended wheel base cab and chassis trucks we started installing the ball directly over the axle and that seemed to be the best ride and handling for the longer WB.

 

There definitely is NO standard. My last 5ver (2002) had enough room to pass by with the tail gate down while my latest one (2004) has about an inch with the tail gate down.