Newbie questions - how to determine which ball mount to buy.

[mherte]

I wonder if there's a legitimate reason is that Forest River doesn't publish the dimensions of their trailers. (At least haven't found the number I'm looking for.)

I have just purchased a 2005 Ford F150 to tow my Flagstaff Hardside pop-up RV and am now trying to determine which ball mount to buy in order to pull the thing. (I had the RV delivered since I had no way of moving it until now!)

According to what I've been able to find online, (Choosing the Correct Ball Mount | etrailer.com) one needs to know (A) the height of the inside top edge of the receiver and (B) the height to the bottom edge of the coupler. Then subtract. The difference if (A) is higher, equals the "drop" or if (B) is higher, the "rise". Another method (Ballmounts - How to Measure) subtracts (C) the difference of the height to the inside top of the coupler from the height of the ball from (A) to determine drop or rise.

This all seem simple enough, I was able to measure the truck side of the equation (A = 16.5") on a flat patch in a parking lot but I don't have a particularly level place at home where the trailer is to make these measurements so I'm unsure of my measurements. Seems it would be easy for the manufacturer to determine either (B) or (C) and state it in the owners manual - would have made this easier for me at least.

Anyone know the height (C or B) of the coupler on a 2013 Flagstaff T12RB or have other ideas on how to be sure I buy the right ball mount the first time? -- Thanks!

[jtstromsburg]

Just adjust the jack on your trailer until the trailer is parallel with your driveway. Then measure to the coupler.

[handbuilder]

For our 2wd F150, we use a 3" drop and a 2" rise for the 4wd Titan with our A-Frame. Why not buy what you think it might be & if wrong height, return it? Youre not going to be stuck with it. If the truck is new to you, you may find that you'll collect a few mounts - we have...we haul a utility trailer, boat, different balls as well as mount lengths for what we are towing and with what vehicle.
You might also go to the A-Frame sub forum and ask there as I think you'll have better response in having actual A-Framers' input...its highly probable someone has your model and can give you the measurement you are looking for. Its likely to be missed by an A Framer in this section.

[KyDan]

Can you maybe borrow a hitch from someone- neighbor, friend, dealer?
Put a hitch/any hitch in your receiver. Drop the A frame onto the ball.
Now with the load on the truck and the truck at towing height-
measure the distance from the road to the A frame hitch.
Now unhitch- crank front jack up/down until A frame is level.
Measure distance from road to A frame hitch again.

Difference in these 2 measurements is what you need to buy.

[mikegp1]

Figure out the measurements and head to Walmart or a auto parts store and you can pick one up. They even sell an adjustable one also.

[mherte]

Originally Posted by jtstromsburg

Just adjust the jack on your trailer until the trailer is parallel with your driveway. Then measure to the coupler.

Guess I'm over-thinking it, JT. I took "level" to mean in both length-wise and across. Parallel to the driveway seems more doable.

Thanks to all for your thoughts and ideas!

Mike