Formula for Determining Turning Clearance with 5th Wheel Trailer

Updated 05/02/2020 | Published 04/30/2020

Question:

B - what does travel refer to here is this equation? and below where did 22 come from? Clearance Formula for Short Bed Trucks Use the formula below to ensure there will be enough space between your truck cab and trailer when executing a 90-degree turn. A+B - C = Clearance A = Distance from the center of fifth-wheel hitch jaw to truck cab B = Length of Travel 14 C = Width of trailer divided by 2 to get half For example: If the distance from the center of the hitch to the cab is 36, 36inch + 22inch = 58. If your fifth-wheel trailer is 102inch wide, take half 51, then plug in: 58inch - 51inch = 7inch of clearance.

asked by: Dave

Helpful Expert Reply:

It sounds like you saw something on our site and either it didn't give clear information or you're combining similar information from two different topics. Maybe not but I guess it doesn't matter I think I can clear it up for you.

The B in the turning clearance formula (A + B) - C = Clearance is the distance of travel from a sliding fifth wheel hitch or the distance a Sidewinder (a rotating pin box) moves the pivot point of a fifth wheel. The 14 inches in the example you saw is the distance the Demco Hijacker, part # DM8550034, you looked at slides.

The 22 inches is referring to a Sidewinder which moves the pivot point 22 inches. This has nothing to do with the Hijacker but the formula is often used to determine if a Sidewinder is a good option for someone so for a lot of people B = 22.

If you're trying to determine if you'll have clearance with a fixed hitch then B = 0.

expert reply by: Charles S