How to design a food truck or trailer that tows well?

There are over 24000 food trucks and trailers in the United States, many of them are designed by a backyard mechanic or a restaurateur who needed a mobile kitchen to feed their family as a 'field expedient', much like in our favorite movie chef.

The catch is that some of these have made some questionable decisions, engineering wise. The physics behind this is not too complicated, hence this blog post. Since for many owners their food truck or trailer is their livelihood and a large financial investment this is a subject very close to our heart. Additionally, almost every food truck or trailer carries several pounds of propane, grease etc. which can liberate itself during a crash and cause damage to life, limb and property making this subject doubly important.

The physics of multi body or connected systems isn't quite the subject of this blog post and is a subject of many engineering text books. In our opinion if a food trailer builder is to take care of three basic things they should be okay.

Picture courtesy: clarksvillenow.com

1. Center of gravity:
   Imagine there is a point in your food trailer that all the mass/weight of the trailer is concentrated in, that point is the center of gravity. As anyone who has driven a go kart or a pick up truck can testify, this point needs to be as low on the trailer as possible. The components that usually tend to be roof mounted are: air conditioners, hoods, shelves, we've noticed some folks trying to mount water tanks on the roof so that taps are gravity fed, this seems like a rather poor idea depending on execution of course. Water is heavy and it sloshes as you take turns or accelerate and decelerate, as a general rule if your trailer is no more than 8ft wide at wheelbase we'd strongly advise against it. Also try to size the components that mount high on the trailer wisely, nice big 12ft hoods are great but also heavy and you may not need to go that big, check with your county's health department on that one! Lastly, if you have storage cabinets or shelves with supplies on the walls, use a bungee cord or such to secure them as a bag of cornmeal in motion can work like a wrecking ball inside the confines of a trailer.

2. Load distribution:
   Think of your food trailer like a metronome, higher the weight is from the pivot wider it swings (higher the amplitude of motion). When you are driving along the I25 beside a tractor trailer, higher amplitude is what you don't want! Besides as normal people we tend to over-correct for such a situation and make the whole thing worse.

   We have also noticed that some folks go the other way around and pile up all the weight to the front of the trailer leaving the tow vehicle rear suspension to be overloaded and the axles of the trailer not sufficiently loaded. This leads not only in the suspension of the tow vehicle giving out but also in the trailer bumping up and down as it goes on the highway leading to a very uncomfortable drive. The thumb rule for this kind of thing is that 60% of the weight should be to the front of the trailer and 40% to the back. Weight distribution in a food trailer

3. Tongue weight:
   A rather (unfortunately) ignored part in design of food trailers is tongue weight. Picture you are holding a club and swinging it, if the weight is all concentrated towards the tip of the club would it not make it more difficult for you to wield the club or to quickly change directions while you swing it about? That's pretty much the case with tongue weight in a trailer. Conversely, very high tongue weight would cause the rear axle and suspension of the tow vehicle to be overloaded and thus wear out quickly. Additionally most tow vehicles are rear wheel driven, so high tongue weight could result in the tow vehicle losing traction in the front wheels during turns in bad weather and cause disaster. Again the thumb rule for this kind of things is 10-15% of the trailer to be on the tongue. You could use a tool like the weigh safe hitch to verify this: https://www.weigh-safe.com/ball-mounts/
   
   

End of the day a food truck or trailer is still an automobile and interacts with a lot of things as it goes on the highway, we think it must hence be designed and built carefully. Of course it's not rocket science and anyone can technically do it if they are careful, we hope you will make the right decisions during your build as it's too important.

If you decide you need some help with this, either designing, building or modifying a food truck or trailer, get in touch with us, we'll take good care of you.

We use computer aided design tools to make sure the weight distribution and behavior of the food truck or trailer along all three axes of motion and rotation are what it should be.