GMC Sierra Truck Cap | Premium Fiberglass & Aluminum Camper Shells
Our GMC Sierra camper shell line is engineered specifically for Sierra 1500, 2500HD, and 3500HD models from 2007 to current year. Every cap is built to OEM tolerances using advanced tooling that mirrors GMC’s own bed dimensions, ensuring flush alignment with your truck’s cab and tailgate. We offer both fiberglass and aluminum construction, each with seamless integration of third brake lights, keyed locks that match your factory ignition, and available power locks.
Whether you’re securing tools for the job site or outfitting your Sierra for weekend camping, our camper shells deliver weather-tight protection without compromising bed access. All fiberglass models include our lifetime paint warranty and UV-resistant gel coat that matches GMC factory colors.
- Custom-fitted for 5’8″, 6’6″, and 8′ Sierra bed lengths across all cab configurations
- Fiberglass models with automotive-grade gel coat in OEM Sierra color matches
- Aluminum frames with powder-coated finish and marine-grade weatherstripping
- Integrated LED third brake light meets FMVSS 108 requirements
- Locking cylinders keyed to match your GMC ignition (optional power locks available)
Material Construction & Finish Options
We manufacture Sierra camper shells in two core materials, each engineered for different priorities. Our fiberglass caps use hand-laid RTM composite construction with Class A automotive gel coat that’s color-matched to GMC’s factory paint codes—Onyx Black, Summit White, Satin Steel Metallic, and 20+ additional Sierra colors. The gel coat is UV-stabilized and carries a lifetime warranty against fading, cracking, or delamination.
Aluminum models feature extruded 6063-T5 alloy frames with welded corner braces and powder-coated surfaces. These caps shed 35-40% of the weight compared to fiberglass, making them ideal for Sierra 2500HD and 3500HD owners who regularly approach GVWR limits. Both materials use the same marine-grade EPDM weatherstripping and stainless steel hinge hardware. Installation hardware is galvanized steel with corrosion-resistant coating, and every cap ships with a complete gasket kit, C-clamp mounting brackets, and detailed torque specifications for your specific Sierra model year.
Bed Length & Cab Configuration Fitment
Sierra 1500 & HD Fitment
Our Sierra caps are available for every bed/cab combination GMC offers. For 1500 models, we stock caps for 5’8″ short beds (Double Cab and Crew Cab), 6’6″ standard beds (Double Cab and Crew Cab), and 8′ long beds (Regular Cab and Crew Cab). HD Sierra owners can order 6’10” or 8′ bed caps, with reinforced roof structures rated for the additional tongue weight common in fifth-wheel and gooseneck towing.
Each cap includes model-year-specific mounting templates. 2014-2018 Sierra caps use a revised rear corner contour to match the C-channel bed rail design GMC introduced that generation. 2019-current AT4 and Denali trims require minor trimming of our standard side skirts to clear the factory bed-step cutouts—we include pre-scored cut lines and a routing guide in those kits. The same steel-reinforced A-pillar design found in our Silverado truck cap lineup carries over to Sierra models, since both GM platforms share core bed architecture from 2014 forward.
Glass Options & Interior Access
Standard glass configuration includes sliding side windows on both sides and a rear sliding or lift-up window. Side glass uses tempered safety glass in bronze tint (standard) or dark tint (optional), both with full-perimeter weather seals and dual-action paddle latches. Rear windows are available in three styles: sliding horizontal (most popular for quick cargo access), vertical lift-up with gas struts, or solid panel with no glass.
All rear glass options include an integrated third brake light assembly using OEM-spec LED modules that tie directly into your Sierra’s factory wiring harness—no splicing required. Interior height clearance is 18.5″ at the bed rail, tapering to 16″ at the centerline for aerodynamic efficiency. We offer optional interior carpeting kits, LED dome lights with three-way switching, and roof racks with T-slot mounting channels for Yakima and Thule crossbars.
Other premium truck caps built for America’s best-selling pickups
What people are saying
Common questions about Sierra camper shell fitment and installation
Our Sierra caps fit 2007-current 1500, 2500HD, and 3500HD models across all bed lengths (5’8″, 6’6″, 6’10”, and 8′). Each cap is manufactured using model-year-specific tooling to account for GMC’s design changes—2014-2018 models use different rear corner contours than 2019-current generations, and we include the correct mounting template for your year. When ordering, you’ll specify your truck’s year, trim level, cab configuration, and bed length to ensure proper fitment.
AT4 and Denali trims with factory bed steps require minor trimming of the side skirts using included pre-scored cut lines. If you have aftermarket bed liners or bed rail caps installed, measure your actual bed width at the rail—our caps accommodate up to 3mm of additional width from most spray-in liners without modification.
Installation is designed as a two-person DIY project requiring only basic hand tools—no welding, drilling, or specialty equipment needed. The process takes 45-60 minutes and uses eight C-clamps that grip your bed rails through threaded inserts in the cap base. We include a detailed guide with photos, torque specifications (18-22 ft-lbs applied in cross-pattern), and alignment instructions.
The most critical step is front bulkhead alignment to match your truck’s cab-to-bed gap, which naturally varies 2-4mm between trucks. We provide shim kits to dial in a flush fit. Many customers complete installation in their driveway, though dealerships and truck accessory shops can perform the service if you prefer professional help. Removal for seasonal storage reverses the same steps with no permanent changes to your Sierra.
Fiberglass caps use hand-laid RTM composite construction with automotive-grade gel coat that’s color-matched to GMC factory paint codes. They’re heavier (approximately 180-220 lbs depending on bed length) but offer superior paint finish and our lifetime warranty against fading or cracking. Fiberglass models are quieter at highway speeds due to better sound damping.
Aluminum caps use extruded 6063-T5 alloy frames with powder-coated finishes, weighing 35-40% less than fiberglass (120-140 lbs). They’re the better choice for Sierra HD owners who regularly approach GVWR limits or need to maximize payload capacity. Aluminum models use the same weatherstripping, glass, and locking hardware as fiberglass, with identical installation procedures. Both materials carry the same structural warranty and roof load ratings up to 500 lbs when properly distributed.
For fiberglass caps, we mix gel coat using GMC’s official paint codes, which are listed on your truck’s door jamb sticker (format: WA followed by 4-6 digits). Common Sierra colors like Onyx Black (GBA), Summit White (GAZ), and Satin Steel Metallic (G1K) are stocked items with 2-3 week lead times. Special-order colors like Cayenne Red Tintcoat or multi-stage metallics require 4-6 weeks for custom gel coat formulation.
Aluminum caps use powder-coated finishes in standard colors (black, white, silver, bronze) or can be custom-matched to your paint code for an additional charge. Keep in mind that powder coat has a slightly different texture than automotive paint, so color-matching on aluminum caps is close but not identical to gel coat precision. We recommend ordering a color sample chip before final production if exact match is critical.
Yes, our Sierra caps include factory roof-rack provisions on most models. We offer optional roof racks with T-slot mounting channels compatible with Yakima, Thule, and Rhino-Rack crossbars. Roof load capacity is 500 lbs when weight is properly distributed across the cap’s structural ribs—adequate for kayaks, cargo boxes, or rooftop tents.
Tonneau covers are not compatible once a camper shell is installed, since the cap replaces the open bed configuration that tonneau systems require. However, many Sierra owners use interior cargo nets, sliding bed trays, or custom drawer systems inside the capped bed for organization. If you need both open-bed functionality and enclosed security at different times, consider our seasonal installation approach—the clamp mounting system allows cap removal in under 30 minutes for summer months when you want open-bed hauling.
Standard models include Southco rotary latches with keys that can be re-keyed to match your Sierra’s ignition cylinder code. During ordering, you’ll provide your VIN, and we work with a locksmith service to cut cap keys from GMC’s code database. This allows one-key operation for your truck doors, ignition, and camper shell locks.
Re-keying adds 1-2 weeks to production time and incurs a small locksmith fee. If you prefer faster delivery, caps ship with standard keys (two per lock cylinder), and you can have a local locksmith re-key them later using your existing GMC key. Optional power lock upgrades integrate with your Sierra’s factory key fob, allowing remote locking and unlocking of the cap along with your truck doors.
Camper shells add approximately 6-8% aerodynamic drag compared to an open bed, which typically translates to 0.5-1.0 MPG reduction in highway fuel economy. City driving shows minimal impact since aerodynamic drag is less significant at lower speeds. The cap’s profile is designed to align with your Sierra’s cab roofline, minimizing turbulence—our fiberglass models use a tapered rear slope that improves airflow compared to vertical-back designs.
Handling changes are negligible for most drivers. Fiberglass caps add 180-220 lbs to your truck’s rear axle, while aluminum models add 120-140 lbs. This weight is within your Sierra’s payload capacity and doesn’t significantly affect braking or cornering. Some owners report improved stability in crosswinds due to reduced bed turbulence. If you tow frequently, ensure the cap’s added weight is accounted for in your trailer tongue weight calculations to stay within GVWR limits.