You could be liable in the event of an accident involving an overloaded vehicle! Not only that, but you could find that your vehicle could be very unstable, unable to brake adequately, ruin wheel bearing, burn-up the brakes, damage the transmission, overheat the engine or cause a tire to blow. What is trailer frontage size? Measure the width and height of the front wall of the trailer and multiply those numbers together. For example, a pop-up camper (when closed) may be about 6-feet wide and 4-feet high, so 24-square feet. If the car or truck has a limitation of 25-square feet of trailer frontage, then you are OK.
Why is there a limit on trailer frontage?
It is because it takes a lot of power to push the air with the front of a vehicle. Obviously, the vehicle doing the towing pushes some of the wind aside, but the turbulence of the air as it swirls around the back of the vehicle creates aerodynamic drag against the front of the trailer. Add that aerodynamic drag to the amount of wind resistance (more aerodynamic drag) of the portion of the front of the trailer that is not in the theoretical shadow of the towing vehicle, and you have a lot of air to push. Aerodynamic drag increases exponentially with road speed (I know exponentially is a term that you haven’t had to use since math classes years ago), so at highway speeds you will discover that the engine and transmission are working overtime. Overtime is ok, but if you go beyond the trailer front square feet stated by the towing vehicle manufacturer, you could overwork your car or truck to the point of exhaustion…which could mean extremely costly damage to the engine or transmission!
It is important to pay attention to the laws in the various states and provinces that limit the total overall length of vehicles and their trailers. This is an issue if you tow any trailer with large motorhome, or tow a very long trailer with a smaller motorhome. Either way, it is a long total overall length that may be in violation of state laws on some roads that are not part of the national (federally funded) highway system. Roads that are designated “US #” and I-# are part of the national highway system and are exempt from vehicle length restriction. The problem comes when you get off of the national roads and are on state and local roads. The most convenient and up-to-date guide is found in the Motor Carrier Atlas by Rand-McNally which is sold in truck stops, or buy it on Amazon.com. This atlas also has useful information that may endanger large vehicles on certain roads, such as low-clearance heights, low weight limits, reduced width limits, and severely steep grades.