What Is a Roof Rack? Rails, Crossbars and Mounting Systems Explained
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A roof rack is a set of bars and mounts on top of your car that lets you carry gear that won’t fit inside: cargo boxes, bikes, kayaks, skis and luggage. Many people use “roof rack” for any roof hardware, but it’s usually made of two parts: side rails that run front to back and crossbars that run side to side.
Table of Contents
The Parts of a Roof Rack
| Part | Runs | What it does |
|---|---|---|
| Side rails | Front to back along the roof edges | Anchor points for crossbars. Often factory-installed |
| Crossbars | Side to side across the roof | Hold the actual load and accessories |
| Towers or feet | Connect bars to the car | Must match your roof type |
| Fit kit or clips | Vehicle-specific pieces | Make the towers fit your car exactly |
| Accessories | On the crossbars | Cargo boxes, bike, kayak and ski carriers |
Roof Types and Rack Styles
- Raised side rails: rails with a gap under them. Crossbars clamp around them. The easiest to fit.
- Flush side rails: rails with no gap. Need specific towers.
- Fixed points: hidden mounting points under small covers.
- Bare (naked) roof: no rails. Towers clamp into the door frames with vehicle-specific clips.
- Gutters: older vehicles and vans with rain gutters.
What Can You Carry on a Roof Rack?
- Cargo boxes and soft roof bags. See rooftop cargo box
- Bikes, kayaks, canoes and paddleboards with the right mounts
- Skis and snowboards
- Ladders and lumber (on work racks)
How Much Weight Can a Roof Rack Hold?
It depends on both the rack and the vehicle. Thule notes that several of its crossbar models have a maximum load capacity of 220 pounds for a pair, but the vehicle’s limit can be lower, and the lowest value always applies. The total includes the rack, any accessories and the cargo. Check your owner’s manual for the roof load limit.
Roof Racks and Fuel Economy
Racks add wind resistance. FuelEconomy.gov notes that hauling cargo on your roof increases aerodynamic drag and lowers fuel economy, and suggests removing racks and boxes when not in use.
Factory vs. Aftermarket Racks
- Factory rails and crossbars: designed for the vehicle, but sometimes have lower load ratings.
- Aftermarket systems (Thule, Yakima and others): wide accessory choice and vehicle-specific fit kits.
- Universal crossbars: cheaper, fit raised rails within a range of widths.
- Please verify the roof rack's compatible dimensions before making your purchase.56-inch long cross rail roof rack mounts to most cars, SUVs, or crossovers with raised longitudinal rails, gap between rail and car roof must be 1/2 inch (1.3cm) and above, distance between two rails must be bigger than 42 inch (107cm) and smaller than 49.6 inch (126cm) , diameter of rail must be within 1.4-2.1 inch (36-55mm). Vehicle fit found in Product Description below.
- Reduced Wind Noise: Rubber sealing strips minimize wind noise for a quieter, more comfortable drive. Refer to the installation video for guidance.
- Durable and Robust: High-quality aluminum alloy construction resists corrosion and supports up to 165 lbs for heavy loads.
- Anti-Theft Security: Features a secure anti-theft locking system with rubber-coated steel clamps and a non-rust lock for added protection.
- Compatibility and Installation Note: For proper fit and safety, watch 2 instructional videos on our detailed page for guidance.
Frequently Asked Questions
What’s the difference between roof rails and a roof rack?
Rails run front to back. A complete rack adds crossbars that run side to side and carry the load.
Can any car have a roof rack?
Most cars can, including bare roofs, using vehicle-specific towers and clips. Some roofs have limited options.
Do roof racks damage cars?
Properly installed racks shouldn’t. Follow the instructions and torque specs, and keep pads clean.
Do I need a roof rack for a cargo box?
Yes, hard-shell boxes mount to crossbars.
The Bottom Line
A roof rack is a system of rails, crossbars and mounts that turns your roof into extra cargo space. Match the rack to your roof type, respect the lowest load limit, and remove it when you don’t need it to save fuel.
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