When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
It should depend on the trailer you are towing. The drop is the distance from the hitch itself to the ball on the ball mount. Most 2004 F-150s I've seen have a standard drop, which is two inches.
My travel trailer receiver has a 1" drop...my brother's ATV trailer requires 4" drop. I have a 4X2...the 4X4 sits higher. I'd stop by uhaul, be suer the trailer is level, and measure how far the top, inside of the ball housing is off the ground. Put your old ball in your hitch and measure how high the top the ball is off the ground. This should tell you how much lower you will need to be. You may want to subtract an inch to the offset to allow your suspension to sink. Be sure you have the right ball size too.
My car hauler needs a 4" drop. My boat uses a 2" drop. As Dr. NO stated, it all depends on what your pulling. you want the trailer to be level. They do make a insert that is adjustable, pricy, but if you only want 1 insert that might be the way to go.
I'd say close to 4"..if you have 18" tires.My xlt has 17" and I use a 3 1/4 " drop I pull a 16 ft trailer and a 17ft bass boat.. It all depends on what size tires and wheels your trailer has, Your trailer wants to be fairly level.
I tow my 7,000lb plus boat with a 1 inch drop turned upside down so in reality it is a 1" rise. This keeps the tow level. My vehicle is a Screw Lariat with 18 inch tires. The trailer has 14 inch tires.
I went by U-haul and measured. Looks like for their little trailers I need a 5 1/4" drop. I guess I am going to have to have more than 1 ball mount. Car Hauler isn't that low and requires a bigger ball.
Keep in mind that as you load the trailer the tongue weight will increase which will put more load on the rear and the rear will go down a bit. So you may not need 5" drop, but something less!