14 Cubic Feet vs 30 Cubic Feet Roof Cargo Boxes in 2026: Key Differences
As an Amazon Associate we earn from qualifying purchases. Links on this page are affiliate links.
Choosing a 14 Cubic Feet vs 30 Cubic Feet roof cargo box depends on your gear volume and vehicle setup. Both options expand your storage capacity, but they differ significantly in construction and installation. The 14 cu ft model is a hard shell that mounts to crossbars, while the 30 cu ft option is a soft bag that can attach without a rack. You need to weigh capacity against ease of use and security features to decide which fits your travel needs.
Key differences
| Aspect | Relaxcabine 14 cu ft Hard Shell Roof Box | FIVKLEMNZ 30 Cubic Feet Roof Bag |
|---|---|---|
| Capacity | 14 cu ft | 30 cu ft |
| Shell Type | ABS + PMMA Hard Shell | 840D PVC Soft Bag |
| Dimensions | 62.5 x 32.48 x 13.19 in | 60 x 43 x 20 in |
| Load Capacity | 150 lb | not listed |
| Installation | Tool-free on crossbars | Straps and door hooks |
| Opening | Dual-side | Top opening |
Which one should you choose?
Choose Relaxcabine 14 cu ft Hard Shell Roof Box if
- You need a rigid, aerodynamic shell that mounts to existing crossbars.
- You prefer dual-side access for quick loading from either vehicle side.
- You require a stated 150 lb load capacity for heavier gear.
Choose FIVKLEMNZ 30 Cubic Feet Roof Bag if
- You have a 30 cu ft volume requirement for large items like multiple suitcases.
- Your vehicle lacks roof racks or crossbars, requiring strap-based installation.
- You want a lightweight option at 12 pounds for easy handling.
Verdict: The 14 cu ft hard shell suits travelers with crossbars who prioritize durability and secure, aerodynamic storage. The 30 cu ft soft bag is better for those needing maximum volume or lacking a roof rack system. Choose based on your specific capacity needs and vehicle mounting capabilities.
Hard Shell vs Soft Bag Comparison
Shell type and build
The Relaxcabine uses a hard shell made from ABS and PMMA materials. This rigid construction offers impact resistance and a glossy finish that withstands sun and rain. It feels solid and protects contents from direct contact. The FIVKLEMNZ is a soft bag made from 840D PVC. It features high-frequency welded seams and a double-layered waterproof cover. While flexible, it lacks the rigid protection of a hard case. The hard shell provides superior durability against debris, while the soft bag is lighter and more compact when folded. You get rigid protection or flexible storage.
Capacity and volume
Capacity is the primary difference between these two carriers. The Relaxcabine provides 14 cubic feet of space. This is suitable for luggage, gear, and camping equipment for shorter trips or smaller families. The FIVKLEMNZ offers 30 cubic feet of storage. This large volume can fit seven to nine suitcases, tents, and sleeping bags. It is designed for SUVs and larger vehicles needing maximum space. If you have bulky items or need to free up interior vehicle space for passengers, the 30 cubic feet option provides more than double the storage volume of the 14 cubic feet model.
Opening and access
Access to your gear varies significantly between these designs. The Relaxcabine features a dual-side opening design. It includes a wide 15-inch passenger-side opening, allowing you to load and unload items from either side of the vehicle. The lid stays open with a sturdy support arm. The FIVKLEMNZ soft bag does not list a specific side-opening mechanism. Soft bags typically open from the top. This means you may need to climb onto the roof or reach over the vehicle to access items. The dual-side access on the hard shell offers much greater convenience for loading in tight spaces.
Load capacity and weight
The weight of the carrier itself and its load limit matter for vehicle safety. The Relaxcabine weighs 30.2 pounds and supports up to 150 pounds of cargo. The FIVKLEMNZ is lighter at 12 pounds. It is designed to hold a large volume of gear, but the specific weight limit is not listed in the data. The hard shell adds more weight to your roof, which may affect fuel economy more than the soft bag. However, the 150-pound limit on the hard shell gives you a clear maximum load to follow. The soft bag is lighter but lacks a stated weight capacity in the provided specifications.
Installation and compatibility
Installation methods differ based on the carrier type. The Relaxcabine uses a tool-free mounting system and attaches to round, square, or most aerodynamic crossbars. It requires existing roof racks. The FIVKLEMNZ is designed to fit all vehicles, including those without roof racks. It uses 10 reinforced straps and 6 door hooks for installation. This makes it versatile for cars, SUVs, vans, and trucks without side rails or crossbars. If your vehicle lacks a roof rack, the soft bag is the only option. If you have crossbars, the hard shell installs quickly with a tool-free system.
Which Roof Cargo Carrier Suits You
Small car owners needing compact storage
The Relaxcabine measures 62.5 by 32.48 by 13.19 inches and weighs 30.2 pounds. Its low 13.19-inch height maintains aerodynamics and fuel efficiency. The 14 cubic foot capacity fits weekend luggage without overwhelming smaller vehicles. Dual-side opening allows access from either side, and the tool-free install works on round or square crossbars.
Families transporting bulk gear without racks
The FIVKLEMNZ offers 30 cubic feet of space in a soft 840D PVC bag. It measures 60 by 43 by 20 inches and fits seven to nine suitcases. The design uses ten straps and six door hooks, requiring no roof rack. This makes it ideal for SUVs or cars without existing crossbars, while the waterproof seams protect contents from rain.
Users prioritizing secure hard-shell protection
This hard shell provides rigid impact resistance against debris and weather. The ABS and PMMA construction supports 150 pounds of load securely. A multi-point key lock system ensures contents stay safe during transit. The sturdy support arm keeps the lid open for easy loading. This setup offers superior durability and security compared to soft fabric alternatives.
Travelers needing maximum volume and portability
The 30 cubic foot capacity doubles your storage potential for long trips. The soft bag weighs only 12 pounds and folds into a compact storage bag when not in use. This lightweight design simplifies handling and storage. The included anti-slip mat and luggage lock add convenience. It expands your vehicle space instantly without permanent installation.
Quick picks
| # | Product | Best for | Price |
|---|---|---|---|
| 1 | Relaxcabine 14 cu ft Hard Shell Roof Box | moderate luggage and dual-side access | Check price of Relaxcabine 14 cu ft Hard Shell Roof Box on Amazon |
| 2 | FIVKLEMNZ 30 Cubic Feet Roof Bag | large loads on vehicles without racks | Check price of FIVKLEMNZ 30 Cubic Feet Roof Bag on Amazon |
The products compared
Relaxcabine 14 cu ft Hard Shell Roof Box
Best for: moderate luggage and dual-side access
- Capacity
- 14 Cubic Feet (what this guide is about)
- Shell Type
- ABS + PMMA
- Opening
- Dual-side
- Load Capacity
- 150 lb
- Water Resistance
- Waterproof
- Security
- Key lock
View on Amazon: Relaxcabine 14 cu ft Hard Shell Roof Box Affiliate link
This 14 cubic feet hard shell cargo box measures 62.5 x 32.48 x 13.19 inches. It is built from ABS and PMMA materials for impact resistance. The unit supports up to 150 lbs of load. Dual-side opening allows access from either side of the vehicle. It features a tool-free installation system and a key lock for security. This model suits travelers needing moderate extra space for luggage or camping gear.
Pros
- Dual-side opening for easy access
- Tool-free mounting system
- Key lock security system
- 150 lb load capacity
Cons
- 14 cubic feet capacity is smaller than 30 cubic feet alternatives
- 30.2 pound weight adds to roof load
- No mention of integrated LED lights or smart tracking
Good fit if
- You need dual-side access for quick loading
- You travel with moderate luggage volume
- You prefer tool-free installation
Skip if
- You require maximum cargo capacity
- You need smart connectivity features
- You have very wide crossbars
Verdict: Relaxcabine 14 Cu Ft Hard Shell Roof Box fits drivers who prioritize convenient dual-side access and secure locking over sheer volume. It is a practical solution for standard road trips where 14 cubic feet is sufficient.
FIVKLEMNZ 30 Cubic Feet Roof Bag
Best for: large loads on vehicles without racks
- Capacity
- 30 Cubic Feet (what this guide is about)
- Shell Type
- 840D PVC soft bag
- Water Resistance
- 100% waterproof
- Security
- Luggage lock
- Installation
- Straps and door hooks
- Vehicle Compatibility
- With or without roof rack
View on Amazon: FIVKLEMNZ 30 Cubic Feet Roof Bag Affiliate link
This soft-sided cargo carrier offers 30 cubic feet of storage in a 60 x 43 x 20 inch footprint. It uses 840D PVC with welded seams for waterproof protection. The design includes 10 straps and 6 door hooks for secure mounting. It fits vehicles with or without roof racks. You should choose this if you need large capacity without a hard shell.
Pros
- 30 cubic feet capacity
- 100% waterproof 840D PVC
- 10 reinforced straps
- Fits vehicles without racks
Cons
- Soft shell is less aerodynamic
- Heavier at 12 pounds
- Larger footprint than hard cases
Good fit if
- You have no roof rack
- You need maximum storage
- You want waterproof protection
Skip if
- You need aerodynamic efficiency
- You prefer rigid shells
- You drive on highways often
Verdict: FIVKLEMNZ 30 Cubic Soft Roof Bag is a high-capacity soft bag for travelers without roof racks. It suits those prioritizing storage volume and weather resistance over highway aerodynamics.
Specifications side by side
| Spec | Relaxcabine 14 cu ft Hard Shell Roof Box | FIVKLEMNZ 30 Cubic Feet Roof Bag |
|---|---|---|
| Capacity | 14 cu ft | 30 cu ft |
| Shell Type | ABS + PMMA | 840D PVC soft bag |
| Opening | Dual-side | not stated |
| Load Capacity | 150 lb | not stated |
| Water Resistance | Waterproof | 100% waterproof |
| Security | Key lock | Luggage lock |
| Installation | Tool-free | Straps and door hooks |
| Vehicle Compatibility | Round, square, most aero crossbars | With or without roof rack |
| Dimensions | 62.5 x 32.48 x 13.19 in | 60 x 43 x 20 in |
| Recommended Use | Luggage, gear, camping equipment | Suitcases, tents, sleeping bags |
| Vehicle Type | not stated | Car |
| Mount Type | not stated | Roof Mount |
| Lockable | Lockable | Lockable |
| Weight | 30.2 pounds | 12 pounds |
| Size | 14 Cu Ft White | 30 Cubic Feet |
| Color | White | Black and Orange |
| Model | Cargo Box 14 Cu Ft White | 30 Cubic Feet |
Frequently asked questions
Can I install a 30 cubic foot roof bag without existing roof racks?
Yes. The FIVKLEMNZ 30 Cubic Feet Roof Bag uses a roof mount design that does not require pre-installed crossbars or racks. This makes it suitable for vehicles that lack a factory rack system. You simply secure the bag directly to the roof. This offers flexibility for drivers who need high capacity but do not have permanent mounting hardware installed on their car.
Which option provides better access to luggage during a trip?
The 14 cubic foot hard shell offers superior access. The Relaxcabine model features dual-side opening, allowing you to load and unload items from either side of the vehicle. This is convenient when parked in tight spaces. The 30 cubic foot soft bag requires you to access the top, which can be difficult if the bag is loaded high or if you are in a narrow spot.
How much weight can a 14 cubic foot hard shell hold?
The Relaxcabine 14 cu ft hard shell supports a load capacity of 150 pounds. This limit applies to the gear you place inside the box. You must ensure your vehicle’s roof rack can also support this weight plus the box’s own weight. The box itself weighs 30.2 pounds, so you need a rack rated for at least 180.2 pounds total.
Is a 30 cubic foot bag aerodynamic for highway driving?
No. The FIVKLEMNZ 30 cubic foot soft bag is not designed for highway aerodynamics. It measures 60 inches by 60 inches by 20 inches, creating a large surface area that increases wind resistance. This can affect fuel efficiency and stability at high speeds. It is better suited for slower travel or off-road use where volume matters more than airflow.
What are the dimensions of a 14 cubic foot roof box?
The Relaxcabine 14 cu ft box measures 62.5 inches in length, 32.5 inches in width, and 13.2 inches in height. These dimensions help it fit on most standard roof racks. The low height of 13.2 inches helps maintain the vehicle’s center of gravity. This compact profile is ideal for standard road trips where moderate luggage volume is sufficient.
Does the 14 cubic foot box include a locking mechanism?
Yes. The Relaxcabine hard shell is lockable. This feature allows you to secure your gear against theft while parked. The lock integrates into the hard shell structure, providing a secure closure. The 30 cubic foot soft bag does not list a specific locking mechanism in its data, so you should verify its security features separately if theft prevention is a priority.
Which roof box is lighter to handle?
The 30 cubic foot soft bag is significantly lighter. The FIVKLEMNZ bag weighs only 12 pounds. In contrast, the Relaxcabine hard shell weighs 30.2 pounds. The soft bag’s lightweight design makes it easier to lift and secure on the roof. This is helpful if you do not have a helper or if you need to move the bag frequently.