Determining Demco Hijacker Autoslide 13k Would Provide Clearance for 2012 Ford F-150 5.5' Bed

Question:

I was reading an answer from jason on a 2012 f150 5.5foot box. For the 2012 Ford F150 with a 5.5 bed, I recommend the Underbed Rail and Installation Kit for Demco Hijacker UMS 5th Wheel and Gooseneck Trailer Hitches # DM8551001 and the Demco Hijacker Autoslide 5th Wheel Trailer Hitch w/ Slider - Single Jaw - Under Bed - 13,000 lbs # DM8550041. This is the only system that does not require you to change your pin box out for a Sidewinder. No other sliding hitch will be compatible, but this system automatically slides to provide you with proper clearance for your trailer and truck. When installing this hitch, the pin in the forward position would have to be 29.5inch from the truck, behind the rear axle to be able to turn 90 degrees with 4 inches clearance. Is this typical? Am I missing something with my calculations? 96/2+4=52inch in the full rear position. Then 52-22.5=29.5inch in the forward position. About 2 inches behind the rear axle. Is this normal? Even with an extended pin, once at 90, the clearance remains the same. Curious if this is the best set up? For best towing, do we need to move the hitch pin forward position in front of the axle? Full 90 is not the important, but want the most safety we can get.

asked by: Tim H

Expert Reply:

It sounds like you might be using the wrong formula to determine if you have enough clearance to make 90 degree corners with your 2012 Ford F-150 with a 5-1/2 foot bed. The formula is:

(A + B) - C = Clearance
A = Distance from the fifth wheel jaw center to the truck cab
B = Offset used (slider clearance)
C = Width of the nose of the trailer divided by 2.

I was able to determine from the numbers you gave that we have the C figure determined and B since we know slider length of the Demco part # DM8550041 which is 22-1/2 inches but we don't know distance from king pin center to rear of truck cab.

expert reply by: Jameson C