Truck Hardware Gatorback Denali Dually Mud Flaps - Set of 4 - Fits 2015-2019 GMC Sierra 3500HD

Part #:
GB1223CUTD~GB2124D~GB756991
Sale Price
$552.60
$614.00
Free Shipping
In Stock Ships by Monday

Additional details

  • Fits 2015-2019 GMC Sierra 3500 HD (Dually Rear Wheel)
  • Front - 5" tire coverage from fender to bottom of flap
  • Rear - 9.5" tire coverage from fender to bottom of flap
  • Includes 12"x23" cut style front flaps (GB1223CUTD)
  • Includes 21"x24" dually rear flaps (GB2124D)
  • Includes custom fit rear support brackets (GB756991)
  • Officially licensed GMC Denali logos
  • Limited lifetime warranty

Front Flap Installation Video

Rear Dually Bracket and Flap Installation

Step by Step Instructions

Dually Mud Flap Set

What you get with the set

Gatorback Plate Finishes

Here are the different plate finishes

At a glance

Overall sentiment is strongly positive: buyers consistently describe Gatorback/SharpTruck mud flaps as premium, heavy‑duty, great-looking, and highly effective at stopping rocks/mud/snow from hitting paint, steps, and trailers. The main reservations are the high price and occasional installation/fitment or hardware/packaging issues, which are often mitigated by responsive customer service and strong warranty support.

What Customers Liked

  • Thick, heavy rubber with substantial weight plates; feels “OTR/semi-truck grade,” doesn’t flap at highway speeds, flexible in cold weather, holds up through winters, gravel roads, mud, and years of use; many repeat buyers across multiple trucks.
  • Significantly reduces rock chips, road debris, mud/salt spray on paint, rocker panels, running boards/power steps, cameras, and keeps trailers/5th wheels/RVs cleaner and protected; coverage often better than OEM or plastic splash guards.
  • Looks “sharp,” classy, and truck-specific; logo/plate options (Z71, AT4X, Ford, Ram, Duramax, flags, black/satin/gunmetal/chrome) get compliments and help the truck stand out; finishing caps appreciated.
  • Many report perfect/vehicle-specific fit with factory-hole mounting, adjustable in/out positioning, good clearance with stock tires, and compatibility with certain trims/fender flares when configured correctly.
  • Generally described as straightforward with the right tools; helpful YouTube videos; bracket kits (especially rear/dually) add stability and make alignment easier; ability to install without removing wheels on some vehicles.
  • Frequent praise for fast shipping, responsive support, quick exchanges for wrong parts, replacement parts/plates/flaps shipped rapidly, and hassle-free warranty (including tears/rips or shipping damage).
  • Replaceable plates; removable lower section on some models for off-road clearance; ability to adjust flap stick-out; some like drilling only into plastic liner (not body).

Things to Consider

  • Most common complaint; many call them expensive/overpriced (often $600–$1000+), sometimes compounded by needing separate bracket kits/plates; some say alternatives may be “good enough” for less.
  • Mixed experiences: some installs are quick, others take hours—especially rear/dually, with wheel-well liners, rock rails/steps, or limited access; right-angle drill and/or removing rear wheels often recommended; alignment can be finicky.
  • Paper instructions sometimes vague, lacking steps, inconsistent with videos, or confusing (hardware ID, left/right orientation, templates, washer placement); requests for better labeling, templates, and model-specific videos.
  • Occasional reports of holes not lining up, needing to drill/elongate slots, bend/trim brackets, trim liners/trim pieces, or create homemade brackets; some rubbing with oversized tires/offset wheels; a few cases of poor fit on specific trims/years.
  • Multiple reviewers note drilling is still required (usually into plastic liner or flap), so ‘no-drill’ feels misleading in some kits.
  • Some dislike plastic clips/nut inserts pulling out/stripping, mixed metric/SAE hardware, bolt length issues, flimsy/galvanized or plastic brackets at high price, silver hardware visible (wish black), occasional missing/mismatched hardware or parts.
  • Some flaps/plates arrived scuffed/scratched or boxes damaged; brackets loosening in transit; a few wrong items shipped or missing pieces (spacers/washers/clips), though support often resolves quickly.
  • Some note low ground clearance depending on model/height; concerns about snagging in deep snow, tall grass, or off-road obstacles; some wish flaps were longer/shorter depending on use.
  • Plate finish can streak/stain (e.g., gunmetal), color/gloss differs from expectations, logos not level in a few cases, and some wish flaps came pre-slotted/pre-drilled for easier install.
AI-generated from the text of customer reviews

Most Helpful

Satisfied Customer
5
I was Skeptical About spending such a large amount of money on mudflaps but these really are the best of the best. Totally worth the investment the videos online or extremely helpful. Installation was easy.  Couldn’t be happier.  I went with the bigger ones and definitely recommend the mounting plate.
These were a snap to install and look great!
5
I really like the way they look.
Perfect
5
You have to get these brackets!! Everything fit perfect. The accuracy of this design was awesome. I’m usually disappointed in the alignment, fit and finish of products like this. Not this time! Went together perfect and made installing a snap. Probably 30 minutes installing the first side and 15 on the second side. Easy!

Most Recent

Mud flaps
5
Very pleased with the quality and easy installation of these mud flaps. Just newly installed, but so far so good.
Love the mud! Flaps top quality
5
Love their customer service. Very very helpful

Can you get just the dental plate for the mud flap

- Michael on 6/23/2023

Will it fit a 2024 gmc sierra?

- Luis on 9/7/2023

Yes

- Admin on 9/8/2023

View all questions

Truck Hardware Gatorback "Denali" Logo Dually Mud Flaps - Set

Add a touch of elegance to your GMC Sierra 3500 HD while protecting it from road debris with the Truck Hardware Gatorback "Denali" Logo Dually Mud Flaps. Specifically designed to fit 2015-2019 GMC Sierra 3500 HD (Dually Rear Wheel) models, these mud flaps combine rugged performance with the premium Denali branding, giving your truck a distinctive and upscale look.

Built from 1/2" thick premium virgin rubber, these Gatorback Denali Dually Mud Flaps are engineered to withstand the toughest road conditions while offering exceptional durability and flexibility. Each rear flap weighs 10 pounds, which helps keep them securely in place without 'sailing' or shifting, even at high speeds. With extensive tire coverage—5 inches for the front and 9.5 inches for the rear—these mud flaps protect your truck from rocks, mud, and other road debris, ensuring your vehicle stays clean and in top condition.

The officially licensed Denali logo is die-stamped into a stainless steel plate with a hand-applied vinyl overlay, guaranteeing a perfect, high-quality finish. The stainless steel plates measure 10 1/4" x 5" on the front and an impressive 17 1/4" x 5" on the rear, providing a premium visual element that complements the sleek design of your truck.

Installation

Front Flap Installation: The front mud flaps fasten directly to the lip of the wheel well using self-tapping screws, and existing factory fasteners can also be used if available. Installation is straightforward and requires only basic tools. Be sure to allow at least 1/2" of clearance between the tire and the wheel well to accommodate the flap's thickness. The front flaps install flush to the wheel well, allowing for seamless integration with accessories like step bars, power boards, or side steps.

Rear Flap Installation: The rear mud flaps come with custom-fit Gatorback dually mounting brackets, which are essential for ensuring a secure and stable fit. These galvanized steel brackets provide a strong mounting point, keeping the heavy-duty flaps firmly in place, even under challenging conditions. The rear brackets utilize existing factory holes, eliminating the need for drilling into the truck body, although drilling through the mud flaps themselves is required. This installation method ensures the mud flaps are tightly secured, reducing the risk of flapping into the tires.

Key Features

  • Premium Virgin Rubber: Made from UV-resistant virgin rubber for superior durability, flexibility, and resistance to cracking—ideal for harsh environments.
  • Custom Fit for GMC Sierra 3500 HD: Specifically designed for 2015-2019 dually models, providing tailored coverage for both front and rear tires.
  • Officially Licensed Denali Logo: Features a stainless steel plate with the Denali logo and black vinyl overlay, adding a premium, branded look to your truck.
  • Durable Rear Support Brackets: Galvanized steel brackets ensure a stable and secure installation, keeping the heavy-duty flaps firmly mounted.

What’s Included

  • (2) Front Mud Flaps - 12" x 23" (GB1223CUTD)
  • (2) Rear Mud Flaps - 21" x 24" (GB2124D)
  • Custom Rear Support Brackets (GB756991)
  • Stainless Steel Self-Tapping Mounting Screws

Tire Coverage

  • Front: Provides 5 inches of tire coverage from the bottom of the fender to the bottom of the flap.
  • Rear: Provides 9.5 inches of tire coverage from the bottom of the fender to the bottom of the flap.

Care & Maintenance

To keep your Gatorback Mud Flaps looking and functioning like new, follow these care and maintenance tips:

  • Virgin Rubber: Clean the heavy-duty rubber portion periodically with mild soap and water to remove road grime, salt, and other buildup.
  • Stainless Steel Plate: Wipe down the stainless steel plates to maintain their appearance and prevent corrosion. Use a non-abrasive cleaner for the best results.
  • Inspect the mounting hardware periodically to ensure it remains secure, especially after off-road use or harsh weather conditions.

Terms

  • Virgin Rubber: High-quality rubber that is not recycled, providing superior flexibility, durability, and resistance to cracking.
  • Sailing: A term used to describe the movement of mud flaps due to airflow, causing them to lift or move out of position, especially at high speeds.
  • Self-Tapping Screws: Screws designed to create their own threads as they are driven into a material, ensuring a secure fit.
  • OEM (Original Equipment Manufacturer): Refers to the quality and design standards set by the original manufacturer, ensuring compatibility and high quality.

Warranty Information

The Gatorback "Denali" Logo Mud Flaps come with a limited lifetime warranty on the rubber portion. This warranty covers any tears or damage from regular use to the original owner. It does not cover brackets, plates, or mounting hardware, nor does it cover damages due to abuse.

Truck Hardware Gatorback "Denali" Logo Dually Mud Flaps offer an exceptional blend of luxury, durability, and protection for your GMC Sierra 3500 HD. Featuring high-quality materials, easy installation, and the prestigious Denali branding, these mud flaps enhance both the style and function of your truck. Choose Gatorback for a premium upgrade that keeps your truck safe and looking great for years to come.

Package Fits These Trucks-

  • 2015 GMC Sierra 3500 HD (Dually Rear Wheel)
  • 2016 GMC Sierra 3500 HD (Dually Rear Wheel)
  • 2017 GMC Sierra 3500 HD (Dually Rear Wheel)
  • 2018 GMC Sierra 3500 HD (Dually Rear Wheel)
  • 2019 GMC Sierra 3500 HD (Dually Rear Wheel)

Brand Gatorback by Truck Hardware
Length 24 inch(es)
Width 21 inch(es)
Height .5 inch(es)
Weight 35 lb(s)

  • 2019 GMC Sierra 3500 HD
  • 2018 GMC Sierra 3500 HD
  • 2017 GMC Sierra 3500 HD
  • 2016 GMC Sierra 3500 HD
  • 2015 GMC Sierra 3500 HD

WARNING: Some products may contain chemicals such as DEHP, which can cause cancer, birth defects or other reproductive harm. For more info go to www.p65warnings.ca.gov