What are the dimensions of a semi truck without the trailer?

Length of the tractor without the trailer could be different for each vehicle make and model. This could best be answered if you had the make and model along with the VIN number for the vehicle. With this information a Dealership for the specified make of vehicle will be able to obtain an answer your question.

The frame rail length, wheel base, and front and rear overhang are all determining factors for overall length.

The tractor I drive is 27 feet in length. My neighbor drives a tractor that is only 25 feet in length, and I have seen some that are in excess of 30 feet in length.