Many posted guides to hitch and ball height are nonsensical.
The reference point for receiver height is the top of the receiver box
. It doesn't really matter whether the top or bottom is used, as long as everyone uses the same reference, and that's the top. You can confirm this by looking at any ball mount and its "drop" or "rise" spec: that dimension is the distance from the top of the receiver opening to the ball mounting surface.
The reference point for trailer height is the top of the ball
, which means the top of the coupler cup (not the bottom of the coupler as shown in some diagrams). This only makes sense, because the top of the ball is where the trailer and the hitch meet.
Some diagrams use the bottom of the coupler because they are cheating
: they ignore the height of the ball itself (always more than the ball diameter, close to 3" for a typical 2" diameter ball) and ignore the depth of the coupler, so two wrongs are not too far off of right. It's not a bad approximation, especially since the tug comes down a bit under load which roughly fixes the error in the calculation resulting from the ball being taller than the coupler.
Originally Posted by cpaharley2008
Right now I'm with a 2" drop with a 2" ball on a Dodge Ram. Mh hitch is 16" from ground to bottom of receiver, it is 20" from ground to the ball top. I'm installing the Andersen and will report it's dimensions.
If the bottom of the 2" square receiver opening
is 16" off the ground, the top is 18" off the ground - there's your receiver height.
With a 2" drop, the top of the ball mount platform is then 16" off the ground.
With a typical ball, the top of the ball is then close to 19" off the ground before the trailer weight pushes the back of the tug down lower than this - Jim, you must be using an unusually tall ball, or your 16" measurement is to something other than the bottom of the 2" square receiver opening.
The top of the ball 20" of the ground is a common travel trailer height, but with every Escape model a little different, I don't know if that's exactly right for a 19' (and Jim's current trailer is a 21').