GMC Sierra 1500 Bed Accessories: Covers, Liners, Toolboxes and Racks That Fit

The Sierra 1500 shares its bed sizes with the Chevy Silverado, so for most steel-bed trucks, the same accessories fit both. But GMC added features Chevy buyers rarely see, and those features are where Sierra owners make expensive mistakes.

The biggest is the CarbonPro bed. Its sidewalls are shaped differently from the steel bed, and owners have warned that normal 1500 bed accessories don't fit it. If you have one, your shopping list is much shorter, and this page shows you exactly what's on it.

Sierra 1500 Bed Sizes by Generation

Lengths are inside floor measurements with the tailgate closed. The Sierra uses the same beds as the Silverado of the same years.

The 2019 redesign widened the bed floor by nearly 7 inches, so covers, liners and mats for 2014–2018 trucks don't carry over to 2019 and newer.

Is Your Sierra Steel or CarbonPro?

Answer this before anything else, because it decides which version of almost every accessory you need.

What CarbonPro is: a carbon-fiber composite bed that GMC introduced on 2019 Sierra Denali and AT4 "CarbonPro Edition" trucks and made more widely available on those trims for 2020. GMC said early on that it could spread to other trims too.

How to tell if you have one:

• Look at the bed surface. CarbonPro has a grained composite finish instead of painted steel.

• Look at the wheel wells. CarbonPro beds come without factory wheel-well liners.

• Check your window sticker. It will list the CarbonPro bed if your truck has one.

Accessories for CarbonPro Beds

Most standard covers exclude CarbonPro beds, and one Sierra owner described a dealer installing a standard cover on a carbon bed where it didn't belong. If your bed is CarbonPro, buy only products that name CarbonPro in their fitment.

These are the CarbonPro-specific covers we've found:

Covers whose listings exclude CarbonPro include the UnderCover Flex and the steel-bed versions of the MX4, Pro X15 and RetraxONE MX.

What about bed liners? GMC designed the CarbonPro surface so that it doesn't need a bed liner. For a CarbonPro bed, a liner is usually unnecessary; if you want a mat to stop cargo sliding, check that the listing names CarbonPro.

Sierra Features That Change What Fits

The MultiPro tailgate

GMC's six-function MultiPro tailgate folds and opens in several ways. Many covers list it as compatible, but some, like the TruXedo Pro X15, come in separate "with MultiPro" and "without MultiPro" versions.

Owners report that a gap between the tailgate's two sections can let water in under any cover. An aftermarket tailgate seal kit usually fixes it, so it's worth adding before blaming your cover.

The 2019 Sierra Limited

Some 2019 Sierras are the "Limited," the old-body truck built alongside the new one for one more year. It takes 2014–2018 accessories. Check your window sticker or decode your VIN if you have a 2019.

Factory side storage boxes

Some covers exclude Sierras with storage boxes built into the bed sides. The exclusion is in the product notes.

Cover height and the power tailgate

A cover sitting slightly low on one side can stop a power tailgate from releasing; one GM owner found his was 1/8 inch low. Clamp the rails evenly and test the tailgate by remote after installing.

The 2027 redesign

GMC redesigned the Sierra 1500 for 2027, so 2019–2026 accessories generally won't carry over. Wait for products listed for 2027.

Sierra Bed Accessories by Category

Tonneau covers

For most Sierras, the BAKFlip MX4 is the best all-round hard cover. It's the easiest hard folder to buy for both bed types, because BAK makes a steel-bed version and a CarbonPro version, and owners report it works with the MultiPro tailgate. For a soft cover, the TruXedo Pro X15 is the pick, with a version for CarbonPro trucks that have the MultiPro tailgate.
Full guide: best tonneau covers for the GMC Sierra 1500.

Bed liners and mats

On a steel bed, choose between a spray-in liner, a drop-in liner listed for your generation, or a rubber mat. On a CarbonPro bed, a liner is usually unnecessary, as explained above.
Full guide: best bed liners for the GMC Sierra 1500.

Tool boxes

Choose between a crossover box behind the cab and a low-profile box under a closed tonneau cover. If you have a CarbonPro bed, check that the tool box's mounting method is approved for it before drilling or clamping.
Full guides: truck tool boxes · tool boxes that fit under a tonneau cover.

Bed racks

A bed rack lets you carry ladders, rooftop tents and bikes above the bed. With a tonneau cover, choose a rack that clamps outside the cover's rails or a cover with T-slot rails, and confirm CarbonPro fitment if your bed is carbon fiber.
Full guides: truck bed racks · bed racks that work with a tonneau cover.

Bed extenders

An extender adds usable length with the tailgate down, useful on the 5'10" short bed. Hitch-mounted extenders work the same on steel and CarbonPro beds, since they mount to the hitch.
Full guide: truck bed extenders.

Other Sierras

• 2014–2018 and 2019 Sierra Limited: see the best tonneau covers for the 2014–2018 Silverado and Sierra.

• Sierra 2500HD and 3500HD: heavy-duty trucks have their own beds, shared with the Silverado HD. See the best tonneau covers for the Silverado and Sierra HD.

• Chevy Silverado 1500: for steel-bed trucks, most Silverado accessories fit the Sierra too. See our Chevy Silverado 1500 page.