Hitch ball height

[teachndad]

Hi,

I was working out the hitch ball height today with my first generation 2000 sienna and my popup trailer.

I got the measurement all worked out, but that's if the trailer and the Sienna are level.

However, real life towing seems to me to be something different. I haven't weighed the tongue yet, but it has two propane tanks on it. So, I am thinking once the tongue is attached to the hitchball, I am going to get some rear end sag. So, I have have an airbag kit in a box in the garage for later installation.

I am estimating the airbag installation will reduce the rear end sag, but not eliminate it. So, should I get a draw bar that sets the hitchball at a height at @1" above the level height for both trailer and my Sienna?

Other pertinant info: popup weighs 1400 lbs dry and is 11' in length. Model year is 1985

I need to to get a draw bar in a few days, as I need to move my trailer to another location, and I don't have time to install the airbags.

Comments please.

BTW, for researchers on this topic, here is a nice simple explanation of finding the hitch ball height.
http://www.accessconnect.com/trailer...hitch_ball.htm

Thanks

Rod W

[brian_bp]

The hitch will drop under load, but since having the trailer nose-down is generally better than having it nose-up, I think that it's better to err in that direction anyway.

Setting the ball height a small amount (such as the proposed 1") high to compensate makes sense to me, but in practice fixed-height ball mounts are not available in very fine rise steps, so just picking the mount which places the ball closest to the right height (not yet accounting for sag) - but not higher - probably works out well.

How much the rear will sag will depend on both hitch weight and the weight of people and cargo in the van. Also, when the air bags are added to the rear springs they can reduce or eliminate the sag... so it's hard to predict where everything will end up, and requirement may change later anyway. Fortunately, ball mounts are pretty cheap and readily available (especially in the 2" size), so a replacement of a different rise can be reasonably purchased if needed.

[jroden]

I think you are better off setting up the loaded trailer and van with the airbags inflated in such a way that the trailer is pretty much level to slightly nose down and the van is as level as you can get it. You can measure at the front and rear wheel wells to set up the airbags and use a level on your popup or just step back and look at it.

I'm towing a heavy trailer with a WDH hitch and once I got the ball setup right it tows quite level even without the airbags. I added the airbags just for laughs though.