The carrying capacity of a utility trailer determines whether you can transfer title in Texas with just a bill of sale.
In Texas, the Department of Motor Vehicles handles utility trailers differently depending on their capacity. A trailer with a gross weight of 4,000 pounds or less doesn't need to be titled, and you can transfer it with a simple bill of sale; but a trailer with a gross weight of over 4,000 pounds must be formally titled and registered at the DMV.
Homemade or Shopmade Trailers
A homemade or commercially constructed trailer with a gross vehicle weight of less than 4,000 lbs. does not need to be issued a Texas title, and can be registered with just a bill of sale. Gross vehicle weight is not the weight of the trailer itself, but the weight of the trailer and its maximum load. Usually, small single-axle utility trailers fall into this category.
Larger trailers, with a gross vehicle weight of over 4,000 pounds, must be issued a Texas title like any other vehicle, and a bill of sale cannot be used to obtain the title. These include most boat trailers, the large-capacity trailers used by some rental or moving companies and trailers capable of carrying equipment or vehicles.
Trailers from out of state weighing more than 4,500 lbs. must be issued a Texas title. An out-of-state title is one of the required documents, and a bill of sale cannot be substituted. Farm trailers weighing 4,000 lbs. or less do not need to be titled or registered; these can be sold with only a bill of sale. Farm trailers weighing more than 4,000 lbs. may be registered with a special farm plate, but do not need to be titled. Farm plates place specific restrictions on a trailer's use