There is a solution, though! Since we don't load our trailers all that heavy, or at least SHOULDN'T be, we don't need any class 3 or class 5 balls. most of our trailers also come with 1-7/8" balls. The trick for better clearance and more "leanability" is to switch to a 2" ball/coupler and buy one of the lower class, cheaper 2" balls. They use a smaller diameter mounting stud making their neck much smaller, allowing the coupler to rotate farther around before binding. Some really cheap ones have a 5/8" stud, but most have a 3/4" or 1", and some class 5's have a 1-1/8" stud. Most motorcycle hitches I have seen come with a 1" hole in them, so if you use a 3/4" stud ball, it will require a 1" to 3/4" reducing bushing. If you can find a 2" ball with a 5/8" stud, all the better for maximum rotation.
The relationship between the diameter of the ball and the size of the neck of the ball is what determines how far over you can lean your bike in corners before causing bind. So, the cheaper, lower class balls will give you the best clearance, but will still be more than adequate for the trailer weights we SHOULD be pulling.
Here are three 2" balls. The first one has a 1-1/8" mounting stud and should probably never be used for a bike towing a trailer. It would give very little ability to lean the bike. The second one has a 1" stud and might be OK for big Harleys that can't lean very far. The last pic is of one with a 3/4" stud and will give the best clearance for really leaning into the turns before binding with the coupler. Couldn't find a pic of a really skinny-necked 2" ball with a 5/8" stud. Just compare the neck sizes to the ball diameter.
