The Thule Motion XL is a large roof-mounted cargo box designed to hold luggage, sports equipment, and other gear on top of your vehicle

The Motion XL is one of Thule's biggest roof boxes — it holds about 18 cubic feet of cargo and works on most vehicles with roof rails or a roof rack system. It mounts on top of your car, truck, or SUV and opens from the side, so you can access your belongings without unloading everything. The box itself is made of hard plastic, which protects what's inside from weather and theft better than a soft bag would.

Before you buy one, you need to know three things: whether your vehicle can physically handle the weight, how much it costs, and whether the side-opening design will work for how you actually pack and travel. This guide walks through what the Motion XL does, what it costs, how to install it, and what to consider before deciding whether it's the right box for you.

Key Takeaways

  • The Thule Motion XL holds 18 cubic feet of cargo and weighs about 75 pounds empty, so your vehicle's roof must support at least 150 pounds total (box plus contents).
  • The box opens from the side rather than from the top, which means you access cargo from one side of your vehicle and may need clearance in parking lots or garages.
  • Installation takes 30 to 60 minutes and requires a roof rack system — Thule makes compatible racks, but other brands work too if they use standard crossbars.
  • Prices typically range from $400 to $600 depending on where you buy and whether you purchase installation, so compare retailers before ordering.
  • The box works best for road trips and regular travel; if you need to access gear frequently or park in tight spaces, a top-opening box or hitch-mounted cargo carrier may suit you better.

Weight limits and what your vehicle can carry

Your vehicle has a maximum roof load rating — the heaviest weight your roof can safely hold. You can find this number in your owner's manual or on a sticker inside the driver's side door jamb. The Thule Motion XL weighs approximately 75 pounds when empty, so if you plan to carry 50 pounds of luggage, your roof needs to support at least 125 pounds total. Most modern cars, SUVs, and trucks can handle this, but some smaller vehicles cannot.

If your roof rating is lower than what you need, you have two options: use a hitch-mounted cargo carrier instead (which attaches to your vehicle's towing hitch rather than the roof), or carry less gear. Overloading your roof can damage the vehicle's structure, affect how it handles on the road, and void your warranty. Check your manual first — do not guess.

How the side-opening design affects packing and access

Unlike some roof boxes that open from the top, the Motion XL opens from the side. This means you pull a handle on one side of the box, and the lid swings out sideways. The advantage is that you can open it even in a garage with low ceiling clearance. The disadvantage is that you need space on one side of your vehicle — if you park against a wall or between two cars, you may not be able to open it fully.

The side-opening design also changes how you pack. You cannot straightforward drop items in from above; you have to slide them in sideways. Long items like skis or fishing rods fit better in a top-opening box. If you frequently need to grab one item without unloading others, a side-opening box is less convenient than a top-opening one. Think about where you typically park and how often you need to access the contents during a trip.

Installation and what you need to get your free guide

The Motion XL requires a roof rack system with crossbars — the horizontal bars that run across the top of your vehicle. If your vehicle came with factory roof rails (the vertical bars running front to back), you will need to buy crossbars separately. Thule sells crossbars designed to fit their rails, but crossbars from other manufacturers work too as long as they use the standard attachment system.

Installation itself takes 30 to 60 minutes. You position the box on the crossbars, align the mounting brackets, and tighten bolts with a wrench. Thule includes instructions and all hardware. Some retailers offer installation for an additional fee — typically $50 to $150 — which can be worth it if you are not comfortable working with tools or want to avoid mistakes. After installation, check the bolts after your first 50 miles of driving to make sure nothing has loosened.

Price and where to buy

The Motion XL typically costs between $400 and $600, depending on the retailer and whether you buy it during a sale. Thule's official website, Amazon, REI, and automotive retailers like AutoZone all carry it. Prices vary, so check a few places before buying. Some retailers offer free shipping on orders over a certain amount, and some include installation or a warranty extension.

If you need a roof rack system as well, add another $150 to $400 to your budget, depending on your vehicle and which rack you choose. Factor in installation costs if you are not installing it yourself. The total investment for a roof box plus rack system can easily exceed $700, so make sure you will use it regularly enough to justify the cost.

Alternatives if the Motion XL does not fit your needs

If the side-opening design does not work for you, Thule makes other boxes. The Motion XT is slightly smaller and also opens from the side. The Thule Touring is a top-opening box that costs less but holds less cargo. If you do not want to install a roof rack at all, a hitch-mounted cargo carrier attaches to your vehicle's towing hitch and opens from the back — it is easier to install and does not affect roof clearance, but it sits lower and can make backing up harder.

Soft cargo bags are the cheapest option — they cost $50 to $200 and strap to your roof rack — but they offer no theft protection and do not keep gear as dry in heavy rain. If you travel only once or twice a year, renting a roof box from a car rental company or equipment rental shop may cost less than buying one. Some people use a combination: a roof box for long trips and a hitch carrier for everyday use.

Maintenance and long-term care

The Motion XL requires minimal maintenance. Rinse it with a garden hose a few times a year to remove dirt and salt, especially if you live near the ocean or in a snowy climate. Check the mounting bolts every six months to may support they have not loosened. The hinges and latch can be lubricated with silicone spray if they become stiff, but this is rarely necessary.

Over time, the plastic can fade from sun exposure, but this does not affect function. If the latch breaks or a hinge cracks, Thule sells replacement parts. The box typically lasts 10 to 15 years with normal use. If you plan to remove it seasonally, loosen the bolts carefully and store it in a garage or shed to extend its life.

Frequently Asked Questions

Does the Motion XL fit all vehicles?

It fits most vehicles with a roof rack system, but you need to check your roof weight limit first. Some smaller cars, older vehicles, and certain truck models have lower roof ratings. Your owner's manual will tell you the maximum roof load. If your vehicle cannot support 125 pounds, a hitch-mounted carrier is a better choice.

Can I leave the Motion XL on my car year-round?

Yes, it is designed to stay on the vehicle. However, leaving it on reduces fuel economy slightly because of wind resistance, and the plastic can fade faster in strong sun. Many people remove it in winter or when not traveling regularly to reduce drag and wear on the roof.

Is the Motion XL waterproof?

It is water-resistant, not completely waterproof. The seal around the lid keeps out most rain, but in heavy downpours or if you submerge it, water may seep in. Use waterproof bags or cases inside for items that cannot get wet, such as electronics or documents.

How much does installation cost if I do not do it myself?

Most retailers charge $50 to $150 for installation, depending on your location and whether you already have a roof rack. Some Thule dealers include installation with purchase. Call ahead to ask about installation fees before you buy.

What is the difference between the Motion XL and other Thule boxes?

The Motion XL is one of the largest boxes Thule makes and opens from the side. The Motion XT is slightly smaller and also side-opening. The Touring is smaller, opens from the top, and costs less. Choose based on how much cargo you need, how you prefer to access it, and your budget.