Why are Flatbed Semi-Truck Trailers Arched?

Erika White
4 Min Read

Trucking is one of the most respectable professions someone can take on, yet there’s a lot of it that people either don’t understand or don’t even realize is a factor in this work.  If you’re interested in coming into this job, you might have noticed something strange about a lot of semis on the road.

Their trailers all seem to curve upward when there’s nothing on them.  Why?

This is the answer to that question and anything else you might wonder about flatbed semi-truck trailers!

Why Are Some Flatbed Trailers Arched?

The main reason that so many flatbed trailers are arched is because of the immense weight that these trucks usually haul.  Although there are trucks out there that haul lighter objects, most are usually carrying items that weigh thousands of pounds.  

The arch in the flatbed is so that when this weight is placed on top, the bed flattens out to a smooth surface instead of dipping far too low.  This allows truckers to carry far more as long as they have the right pintle hitch and have checked their weight limits.  

Over time this arch may decrease or straighten out, especially if a truck is hauling goods that are severely heavier than the average.  If that’s the case, there’s no repairing this.  It’s better to scrap or sell the old bed and get a new one rather than deal with what could happen if you have too much weight on an un-arched bed.

What’s the Point of a Trailer Tail?

A trailer tail is a mount at the rear, also called boat tails or trailer wake devices.  This helps with bowing because it modifies airflow and ensures that you don’t cause a strong buffer or another issue with the vehicles around you.  The smoother your drive is, the safer it is for everyone else included.  Make sure to do your homework, and talk to whatever company owns the vehicle if you don’t, before updating your flatbed with tools s it might not need.

What Would Happen With an Un-Arched Bed?

The less a bed is arched, the less it can generally carry.  If a bed is flat before you set the goods on it, then it has nowhere to go but down.  This can cause issues like items being rattled around more, the bottom of the trailer hitting the ground, or speed bumps, and can make it so that your tires have to be rotated more often because they’re wearing unevenly.  

If a flat trailer bed is bad enough, it can even crack or break inwards, possibly ruining hundreds of thousands of dollars of goods.  It’s important that before you put any load on, and after you take the load off, you check the way your trailer’s bed looks and if it’s not bowing at all or if it’s even bowing down slightly.  It could be time to replace that trailer bed.

Every Trailer is Built Differently

Although it may seem like almost every trailer bed is arched: many aren’t.  Consider the weight of what you’re hauling, and the strength of your trailer, before making any hauls.

Share This Article
Erika White is a graduate of Parsons School of Design. Erika is based in Manhattan but travels much of the year. Erika has written for NPR, Motherboard, MSN Money, and the Huffington Post. Here at Morning News Ledger, Erika covers entertainment stories, focusing on performance arts and culture.