Rivian R1 Running Boards, Mud Flaps, and Front Plate Mounts

Exterior accessories are where an R1 order goes wrong most expensively. Cabin parts drop in and come back out. Exterior parts bolt to brackets, reuse fender fasteners, or key into a front fascia — and every one of those interfaces is something a listing can get wrong or a buyer can misread. The three products in this category also happen to be the three highest-verification items in the R1 catalog: one is the only Advanced install, one is model-specific rather than shared, and one is locked to a single generation.

This guide covers what each one actually attaches to, and what to confirm on your own vehicle before ordering.

The Verification Burden, Ranked

Running Boards: The One Advanced Install

The R1 aluminum running boards are a two-piece side step kit supplied with vehicle-specific mounting brackets, listed for R1T and R1S across 2022 through 2026. The year range spans both generations, and the model coverage spans both vehicles, which sounds like the easiest purchase on this page. It is the hardest, and the reason is the brackets.

A side step is a structural accessory. It carries a person's full weight, repeatedly, often with a wet boot, sometimes with a child using it as a ladder. That load path runs through brackets into underbody mounting points, which means three things have to be right that a year range does not tell you:

• Bracket placement. The brackets have to land on the intended points, not merely somewhere that accepts a bolt.
• Underbody clearance. An R1 has hardware under the floor. A bracket that fits geometrically but crowds something else is not a fit.
• Included hardware. Confirm what actually arrives in the box against what the install requires, before the truck is on stands.

This is rated Advanced in our catalog for exactly these reasons, and it is the one product in the R1 lineup where we would suggest paying a shop rather than working it out in a driveway. The failure mode is not cosmetic. A step that seems seated and is not is a step someone falls off.

One more consideration specific to an electric truck: work under the vehicle means respecting lift points and the pack. If you do not know where an R1 is safe to support, that alone is the argument for professional installation.

Mud Flaps: R1S-Specific, and Read the Word "No-Drill" Carefully

The R1S no-drill mud flaps are a four-piece splash guard set covering front and rear wheel arches, designed to use existing R1S mounting locations, listed for 2022 through 2026.

Note what this product is not: it is not a shared R1 part. Unlike the console and screen products, wheel-arch geometry differs between the R1T and the R1S, and this set is presented for the SUV. R1T owners should not treat it as a cross-fit.

On the "no-drill" claim, the catalog records it the way the listing states it — as the seller's description of the installation, not as a guarantee, and the fitment note says to confirm the included fasteners before starting. That phrasing is deliberate. No-drill splash guard designs almost always work by reusing fasteners that are already in the fender liner: existing screws, push clips, or factory holes hidden behind the liner edge. When that goes to plan it is a genuinely easy job. When the set arrives without the right clips, or the existing fasteners are seized or already broken from a previous removal, "no-drill" becomes "no-drill plus a trip for hardware." We rate it Medium rather than Easy on that basis.

What flaps actually buy you is worth being honest about. They reduce spray and stone strike along the rocker panels and lower doors, which is real protection on gravel, salted winter roads, and construction sites. They do not make the vehicle waterproof, and flush no-drill flaps sit closer to the body than bulky off-road flaps, so expect meaningful improvement rather than elimination. The secondary benefit is interior: less grit thrown up means less of it tracked into the cargo area, which pairs with the liner recommended in our R1S cargo setup guide.

Front License Mounts: Generation-Locked, Full Stop

The Gen 2 no-drill license mount is a removable, height-adjustable front plate bracket for second-generation R1T and R1S — model years 2025 and 2026 only. Its listing states plainly that Gen 1 grille compatibility should not be assumed.

This is the clearest generation lock in the R1 catalog, and the engineering reason is straightforward. A no-drill front plate bracket has to grab existing fascia geometry precisely enough to hold a plate at highway speed without a single hole in the bumper. That makes it a shape-matched part by definition. A bracket designed against the Gen 2 front end has nothing correct to key into on a Gen 1, and forcing it is how people end up drilling the bumper they bought a no-drill mount to avoid.

For owners in states that require a front plate, the appeal is obvious: adjustable height, removable when you do not need it, and no permanent modification to the fascia. Just confirm your generation first — the Gen 1 vs Gen 2 compatibility guide covers how to check from the door jamb label rather than the delivery year.

Sequencing: Which of the Three to Do First

These three products do not compete, but they do have a sensible order, and it is not the order of price.

Mud flaps first, if you own an R1S and drive on anything but clean pavement. They are the cheapest of the three, the least risky to install, and the only one that prevents damage rather than adding capability. Rock chip along a rocker panel is cumulative and permanent; every month without flaps on gravel or salted road is chips you cannot undo. This is also the item whose benefit compounds with interior protection, since less spray means less grit tracked into the cabin and cargo area.

Front plate mount second, if your state requires a front plate and you own a Gen 2. Not because it is urgent, but because the alternative — living with a plate zip-tied to the fascia, or drilling — gets worse the longer it goes on. It is an Easy install and fully removable, so there is little reason to defer it.

Running boards last. They are the largest outlay, the only Advanced install, and the only one on this list that is a convenience upgrade rather than protection. There is no penalty for waiting until you have found a shop you trust or a weekend with proper stands. And because they are the one item where a bad install has a genuine injury mode, waiting is the correct instinct rather than a failure of nerve.

One note on winter specifically: if you live where roads are salted, do the flaps before the first storm rather than after. Salt spray into wheel wells and along rockers over one season does more visible harm than a year of dry-weather driving.

What Rivian Says About Accessory Installation

Rivian's own owner guidance covers accessory mounting, cargo and roof loads, recovery points, cameras, sensors, and electrical connections, and it is the authority for your specific vehicle rather than any accessory listing. Two implications for this category in particular:

1. Recovery points and sensors are not mounting surfaces. A bracket that shares space with either needs to be confirmed against Rivian documentation, not eyeballed.
2. Load-bearing accessories have limits set by position. That applies to steps and crossbars alike, and the rating belongs to the installed combination, not the part in the box.

Before You Buy

• Treat running boards as shop work unless you are confident about R1 lift points and underbody clearance.
• Confirm bracket placement and included hardware before the vehicle goes on stands, not after.
• Do not cross-fit R1S mud flaps to an R1T; wheel-arch geometry differs.
• Confirm the fasteners included with any no-drill flap set before starting.
• Verify your generation from the door jamb label before ordering a front plate mount; the Gen 2 bracket is 2025-2026 only.
• Keep cameras, sensors, recovery points, and safety labels clear of anything you bolt on.
• Per-product fitment notes live on the R1T and R1S accessory hubs.

Last updated: August 2026