Peterbilt 357/378 Mud Flaps

Frequently Asked Questions About Peterbilt 357/378 Mud Flaps

Will these mud flaps fit my specific year Peterbilt 357 or 378?

Our Peterbilt 357/378 mud flaps are designed to fit models from 1986 through 2007. The mounting brackets and hole patterns are compatible across all years within this range. However, if your truck has aftermarket fenders or custom modifications, we recommend measuring your current setup or contacting our support team with your OEM for verification.

What's the difference between rubber and stainless steel backed mud flaps?

Rubber mud flaps are more economical and provide excellent flexibility, making them ideal for standard highway use. They typically last 2-3 years with regular use. Stainless steel backed options feature a heavy-duty rubber flap reinforced with a polished or brushed stainless plate, offering superior durability and a premium appearance. These are recommended for heavy-duty applications or drivers wanting maximum longevity and style.

Do I need special tools or brackets to install these mud flaps?

Most installations require basic hand tools including a drill with 3/8" and 1/2" bits, socket wrenches, and mounting hardware (typically included). Factory mounting points can be used on most 357/378 models. For trucks without existing brackets, universal mounting brackets are available separately. Installation typically takes 30-45 minutes per side for experienced mechanics.

What size mud flaps do I need for my Peterbilt 357/378?

Standard sizes for these models are 24" x 30" for the rear and 24" x 24" for the front positions. However, if you have oversized tires, a lifted suspension, or wide-base singles, you may need 24" x 36" or custom sizes. Measure from the bottom of your fender to approximately 6-8 inches from the ground for proper coverage and DOT compliance.

How do anti-sail mud flaps differ from standard ones?

Anti-sail mud flaps feature weighted bottom edges or internal steel rods that prevent the flaps from blowing back at highway speeds. This design maintains better spray protection and reduces wear from constant flexing. They're particularly beneficial for long-haul drivers or those frequently traveling at high speeds. Standard flaps work well for local and regional applications where speeds are more moderate.