Frequently Asked Questions About Peterbilt 357/378 Fairings & Steps

Will these fairings and steps fit my specific year Peterbilt 357 or 378?

Most aftermarket fairings and steps for Peterbilt 357/378 models are designed to fit trucks manufactured from 1987 through 2007. However, there can be variations between model years, particularly in mounting hole patterns and bracket designs. We recommend checking the specific product description for year compatibility or contacting our customer service team with your VIN number to ensure proper fitment. Some fairings may require minor modifications for trucks with custom bumpers or non-standard configurations.

What's the difference between fiberglass and aluminum fairings, and which should I choose?

Fiberglass fairings are lighter weight, more affordable, and easier to repair if damaged, but they can crack under extreme stress and may fade over time. Aluminum fairings are more durable, resist corrosion better, and maintain their finish longer, but they're heavier and typically cost 30-50% more. For drivers in harsh weather conditions or those prioritizing longevity, aluminum is often the better choice. Fiberglass works well for most applications and offers better fuel economy due to the weight savings.

How difficult is the installation process, and what tools will I need?

Installation difficulty varies by product, but most fairings and steps can be installed in 2-4 hours with basic tools. You'll typically need a drill with metal bits, socket wrenches, measuring tape, and a level. Some installations require cutting or drilling new mounting holes. Battery box covers and quarter fenders are generally straightforward bolt-on applications, while full fairing sets may require alignment adjustments and additional brackets. Professional installation usually runs $200-400 if you prefer not to do it yourself.

Do aftermarket steps meet DOT requirements and support the weight they claim?

Quality aftermarket steps from reputable manufacturers meet or exceed DOT requirements and FMCSA regulations for commercial vehicles. Most steps are rated for 300-500 pounds per step, with reinforced mounting brackets. Look for steps that specifically state DOT compliance in their product descriptions. Avoid extremely cheap options that don't list weight ratings or compliance certifications, as these may not hold up under daily use or pass inspection.

What finish options are available, and how do they hold up to road conditions?

Common finishes include polished stainless steel, chrome-plated steel, powder-coated aluminum, and raw aluminum. Polished stainless steel offers the best long-term appearance with minimal maintenance but costs more. Chrome looks great initially but can pit and peel in salt-heavy environments. Powder coating provides excellent corrosion resistance and comes in various colors but may chip if struck by debris. Raw aluminum develops a natural protective patina and is virtually maintenance-free but lacks the mirror finish many drivers prefer.