Understanding Truck Trailer Side And Back Panels

Have you ever found yourself traveling behind a semi wondering what those big panels hanging off the back were for? At first glance, it might even look like the doors of the trailer are hanging open. Well, rest assured, they are not doors left flapping in the breeze. Rather, they are panels purposely mounted to the back portion of the semi’s trailer (and sometimes the undercarriage) and serve a very specific purpose indeed.

Those Mysterious Panels

The panels that seem suspended from the rear of the trailer are sometimes called boat tails but are more frequently referred to as trailer tails or rear trailer fairings. The panels under the body of the truck are referred to in a number of ways: side skirts, side panels, or aerodynamic panel skirts. What are they for? In a nutshell – to save fuel and reduce drag.

Fuel efficiency is improved through the use of these mysterious side panels because they reduce drag on the wheels and undercarriage of the rig. Around the vehicle’s rear wheels, drag is reduced by tail fairings. Seriously though, how much fuel could possibly be saved by a couple of panels? The answer may surprise you. The average is about a 10% fuel savings (with some savings reported being as high as 15%, while others hovered at a mere 5%).

When the panels are not in use and need to be out of the way (such as loading and unloading stops), they simply fold back.

Why Were These Panels Created?

Growing environmental concerns and a reaction to rising fuel prices may have been the reasons for the initial invention of these panels. But they certainly have not been a recent addition to the transport community. Railcars, back in 1935, started the idea in an effort to streamline railroad vehicles. Through the decades, any number of patents have been filed for different styles of these panels. And though they really got popular around 2008, they were seen on a relatively regular basis as early as 2004 (an approximation).

Why Doesn’t Every Truck Have These Panels?

Every truck on the road will not benefit from these panels. The importance of drag reduction becomes more significant as truck speeds increase. Between 60 and 65 mph, these panels really come into play. So, for a truck that simply concentrates on local deliveries, and such, the panels don’t make a whole lot of sense.

Another reason that not every trailer load is going to have these panels mounted on the back is cost. It can be rather unmanageable for some truckers. Volume discounts are sometimes available for fleet owners, but the price for a set of these tails will well exceed $2000.

If you own a fleet of transport vehicles, or if you would simply like to accessorize/repair your own vehicle and/or trailer, look no further than Mickey Genuine Parts. We carry all kinds of parts, accessories, and used trailers. We even have a number of custom parts available. Contact us today to see what Mickey Genuine Parts can do for you.

Let’s keep truckin'.

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