Truck-to-5th-Wheel Trailer Clearance Distances for '99 Sunnybrook and 2003 Dodge 2500 Long Bed  

Question:

Expert Reply:

We do recommend certain minimum clearance distances between a 5th wheel trailer and the truck's bedrails, tailgate and rear bumper. The diagram I have linked for you at right shows these recommended minimums for safe 5th wheel towing.

Between the top of the bed rails and the bottom of the trailer overhang we suggest no less than 5-inches of vertical clearance; between the truck's tailgate and the front of the trailer no less than 4-inches when making turns; and between the rear edge of the bumper and the front of the trailer no les than 16-inches.

Most pin boxes have multiple mounting holes on their brackets to allow adjustment of the box's height relative to the trailer's pin box mounting wings. If your Leland 7920 pin box is not mounted in the lowest possible position on the trailer wings you may be able to mount it lower, which will have the effect of lifting the front of the trailer's height relative to the truck bed rails. Depending on the design of the trailer this may have no effect on front-to-back clearance at the bumper and tailgate.

Of course, the ideal towing state is for a trailer to be close to dead level when it is hitched.

Minor tilt may be acceptable but too much tilt can lead to sway. There are also issues with doing an axle flip, installing longer spring hangers or increasing tire diameter. These modifications may gain you a bit of height in the trailer but this will come at the cost of increased sway from the higher center of gravity. Also the handling characteristics of the trailer will change and generally not for the better. The higher the trailer is from the road surface the more that wind and passing vehicles will affects its ride.

The best solution is to change the truck or trailer to achieve a compatible combination.

expert reply by: Adam R

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