If you want a dedicated, weather-resistant storage solution to protect your RV gear from wind and rain, choose KNOX 5th; if you need heavy-duty mechanical dollies to safely move and store cars or trucks in a garage, choose AutoBull Mechanical 1500-lbs. These two products solve entirely different problems for vehicle owners, and confusing them would be a costly mistake. The KNOX skirt is designed specifically for the undercarriage of fifth-wheel trailers to hide clutter and shield equipment from the elements, while the AutoBull set is a robust tool for lifting and rolling passenger vehicles on flat surfaces. One protects your campsite setup, and the other facilitates maintenance in your workshop. I have analyzed the specifications and design intent of both items to help you decide which one belongs in your arsenal, keeping in mind that for hybrid cars, the mechanical advantage of the AutoBull system offers a clean, leak-free way to position the vehicle without damaging its battery systems or floor.
• KNOX 5th: Its biggest strength is the modular, tear-resistant fabric construction with twist fasteners that create a secure, low-profile barrier against the weather. Its trade-off is that it is strictly an accessory for fifth-wheel trailers and cannot be used for moving vehicles or general cargo transport. This pick is for RV owners who prioritize organized, hidden storage for outdoor gear and want to keep their rig looking clean during travel.
• Its trade-off is its sheer weight and bulk, making it impractical for road trips or compact storage compared to lighter plastic alternatives. This pick is for home mechanics and garage owners who need reliable tools to move cars, trucks, and SUVs without worrying about oil leaks or complex setups.
The KNOX 5th Wheel RV Skirt is engineered for a very specific environment: the road and the campground. If you own a fifth-wheel trailer, you know that the space underneath the front overhang is often a black hole where mud, debris, and lost keys go to die. This product transforms that dead space into a functional storage locker. The design focuses heavily on durability through the use of Apex 600D material, which is explicitly coated with PVC to resist water, UV exposure, and tearing. You are not just buying a piece of cloth; you are buying a shield that stands up to strong winds and changing seasons.
What makes this product particularly useful for the traveler is the security of the closure system. The heavy-duty twist fasteners are built to hold firm until you actively release them. Unlike simple Velcro or bungee cords that might snap loose in a high-speed gust, these fasteners adapt to your setup in seconds but stay put when you need them to. The zipper doors on all three sides allow you to load and unload items like BBQ sets, camp chairs, or bicycles quickly, yet keep them completely concealed. This low-profile black finish helps maintain the aesthetic of your rig, ensuring that your camping gear doesn't look messy when you are parked at a scenic overlook.
We compare products from their published specs and features; the verdicts below are our independent editorial opinions.
Updated: 2026-11-07 · 7 min read · Independent comparison
However, this product is not for everyone. If you do not drive a fifth-wheel trailer, this item is useless to you. It is also not designed to bear heavy loads on top of itself; it is a container, not a platform. You should skip this if you are looking for something to move vehicles around a driveway or if you need a cover that encloses the entire vehicle rather than just the undercarriage. It fits best with users who want to pair it with a matching KNOX RV cover to outfit their rig from top to bottom, creating a cohesive protection system for long-haul storage and travel.
The AutoBull Mechanical 1500-lbs Car Wheel Dolly Set is built for the garage floor. This is a tool for people who need to reposition heavy machinery, such as cars, trucks, and SUVs, without straining their backs or damaging their concrete floors. The standout feature here is the mechanical pedal jack. Unlike hydraulic systems that rely on fluid and can eventually develop leaks—a major headache for anyone storing a car for months—the AutoBull uses a maintenance-free mechanical system. This provides superior leverage and eliminates the risk of oil spills ruining your garage floor or the vehicle's paint job.
The load capacity is genuinely impressive for a manual system. The double steel rollers accommodate standard tires up to 9 inches wide, ensuring a secure cradle for almost any passenger vehicle. Once the vehicle is lifted by the ratcheting foot pedal, the four-inch ball-bearing swivel casters take over. These omnidirectional wheels allow a single operator to maneuver a disabled vehicle around tight corners with ease. You can spin the car 360 degrees without dragging it, protecting the tires from developing flat spots during seasonal storage.
This product is ideal for the DIY mechanic or the owner of a classic car who needs to move it around a tight workspace. It is also excellent for hybrid cars, as the mechanical nature ensures no hydraulic fluids come near the sensitive undercarriage components that often house battery packs. However, you must be prepared for the physical reality of the unit. They are substantial pieces of equipment meant to stay in a shop or garage. If you need something portable enough to carry on a camping trip, this is not the right choice. But if you need a permanent, reliable solution for vehicle movement, the sturdy build and comprehensive warranty make it a serious contender.
• Best for RV Undercarriage Storage → KNOX 5th: Only the KNOX model is designed to fit the specific dimensions of a fifth-wheel tongue and provide a zippered enclosure for gear.
• Best for Moving Vehicles → AutoBull Mechanical 1500-lbs: The AutoBull dolly set is the only option capable of lifting and rolling cars, trucks, and SUVs on flat ground.
• Best Weather Protection → KNOX 5th: The Apex 600D fabric with PVC coating offers dedicated resistance to wind, rain, and UV rays, which the metal dollies do not provide.
• Best for Maintenance-Free Lifting → AutoBull Mechanical 1500-lbs: The mechanical ratcheting pedal eliminates oil leaks, a common failure point in hydraulic systems, making it safer for long-term storage.
• Best for Tight Garage Maneuvering → AutoBull Mechanical 1500-lbs: The 360-degree rotation and ball-bearing casters allow a single person to pivot heavy vehicles in confined spaces.
• Best for Customizable Fit → KNOX 5th: The detachable panels and hook-and-loop fasteners allow you to tailor the skirt to exact hitch dimensions, whereas the dollies have fixed roller widths.
I recommend the KNOX 5th Wheel RV Skirt for anyone who owns a fifth-wheel trailer and wants to maximize their outdoor utility without sacrificing aesthetics. The combination of weather-resistant fabric and secure twist fasteners solves the real-world problem of exposed gear in a way that few other products do. Conversely, if your primary goal is maintaining a vehicle in a home garage, the AutoBull Mechanical 1500-lbs set is the superior investment. Its mechanical pedal jack and robust steel frame offer peace of mind regarding leaks and structural integrity that hydraulic systems simply cannot match. For hybrid cars specifically, I lean toward the AutoBull system because the clean, mechanical operation keeps fluids away from the sensitive battery components located under the chassis, ensuring safety during positioning. Ultimately, you are choosing between a protective shell for your adventure rig and a powerful tool for your workshop; knowing which problem you need to solve makes the decision clear.
No, the KNOX 5th is specifically engineered for fifth-wheel trailers with a cutout for extra-large tongues and hitch protrusions. It will not fit standard bumper-pull trailers or other vehicle types.
No, the AutoBull set operates entirely mechanically using a ratcheting foot pedal jack. It requires no electricity, batteries, or hydraulic fluid, making it a maintenance-free solution for lifting vehicles.
Yes, the Apex 600D fabric is designed to withstand diverse weather conditions, including strong wind, rain, and cold. The twist fasteners are built to hold securely through harsh seasons without needing constant adjustment.
No, the heavy-duty ball-bearing swivel casters are designed to roll smoothly without scuffing or damaging concrete floors, allowing for safe repositioning of heavy vehicles in tight workshop spaces.
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