What Is a Super C RV? Chassis, Brands and Fuel Security

## What Is a Super C RV? A **Super C RV** (also called a **Super C motorhome**) is a motorhome built on a heavy-duty commercial truck chassis instead of the lighter cutaway van chassis used on a standard Class C. You still get the familiar cab-over bunk or storage area and a truck-style cab, but underneath is the frame, engine and brakes of a medium-duty work truck. That makes a Super C a middle ground: easier to drive and park than many Class A diesel pushers, but with far more power, towing capacity and cargo capacity than a regular Class C. ## Common Super C Chassis Super C motorhomes are built on several commercial chassis. Knowing yours matters, because it decides your engine, your towing rating and where your fuel fill sits. - **Ford F-550 and F-600** with the 6.7L Power Stroke diesel. This is the most common Super C chassis. See our [Ford F-550 and F-600 Super C buyer's guide](/blog/super-c-motorhome-buyers-guide-ford-f550-f600). - **Freightliner S2RV** with a Cummins diesel, used on larger coaches built for heavy towing. - **Ram 5500** with a gas engine, a lower-cost Super C option. - **Chevrolet and GMC** medium-duty chassis. See the [Freightliner S2RV and Ram 5500 guide](/blog/super-c-buyers-guide-freightliner-s2rv-ram-5500) and the [Chevrolet and GMC chassis guide](/blog/class-c-super-c-buyers-guide-chevrolet-gmc-chassis) for model-by-model details. ## Super C vs. Class C vs. Class A | | Class C | Super C | Class A | |---|---|---|---| | Typical chassis | Ford E-350 / E-450, Chevrolet 3500 / 4500 | Ford F-550 / F-600, Freightliner S2RV, Ram 5500, Chevrolet / GMC medium-duty | Ford F53 / Workhorse (gas), Freightliner and others (diesel) | | Typical engine | Gas | Mostly diesel (Ram 5500 is gas) | Gas or diesel | | Towing | Light to moderate | Heavy | Moderate to heavy | | Driving feel | Van-like | Truck-like | Bus-like | If you are comparing a standard Class C, start with our [Ford E-350 and E-450 Class C guide](/blog/class-c-motorhome-buyers-guide-ford-e350-e450). For gas Class A coaches, see the [Ford F53 and Workhorse guide](/blog/class-a-gas-motorhome-buyers-guide-ford-f53-workhorse). ## Popular Super C Motorhome Brands ### Dynamax Super C Dynamax is one of the best-known Super C builders, with the **Isata 5**, **Isata 6**, **Force HD** and **DX3**. See [Dynamax locking fuel doors](/lp/dynamax). ### Entegra Super C Entegra Coach builds the **Accolade XL** and **Esteem XL** Super C models. See [Entegra Coach locking fuel doors](/lp/entegra-coach). ### Jayco Super C The **Jayco Seneca** is Jayco's Super C, offered on Ford and Freightliner chassis. See the [Jayco Seneca locking fuel door](/lp/jayco-seneca-locking-fuel-door). ### Other Super C Builders You will also find Super C models from **Thor** (Four Winds and Chateau Super C), **Holiday Rambler** (Incline), **East to West** (Bravado) and **Nexus**. Use [Find My Fit](/find-my-fit) to check your exact year, model and floorplan. ## The Problem: Exposed Fuel Fills Commercial truck chassis were designed for fleet refueling, not overnight parking at campgrounds. On most Super C motorhomes the diesel or gas fill, and the DEF fill on diesels, sits behind a basic fuel door with no lock, or is open on the side of the chassis. That leaves your fuel exposed to: - **Fuel theft and siphoning.** A Super C tank holds a lot of expensive diesel. Read [can someone siphon gas from your motorhome?](/blog/can-someone-siphon-gas-from-your-motorhome) - **Tampering.** Sugar, water or dirt in the tank can mean a tow and a costly repair. Read [what happens if someone puts sugar in your RV gas tank](/blog/what-happens-if-someone-puts-sugar-in-rv-gas-tank). - **DEF contamination** on diesel models, which can damage the emissions system. A [locking gas cap](/lp/locking-gas-cap) helps, but it only covers one fill and can still be pried off. Compare the options in [locking gas cap vs. locking fuel door](/blog/locking-gas-cap-vs-locking-fuel-door-rv). ## The Fix: The RV Fuel Vault™ **The RV Fuel Vault™** is a locking, theft-resistant steel fuel door made for motorhomes, including Super C models. It covers the fill area, locks with a key and installs with security screws that are included with the door. - Helps stop fuel theft, siphoning and tampering - Covers the fill area, not just one cap - Built for Motorized RVs on Ford, Freightliner, Ram and Chevrolet chassis See the [Super C motorhome fuel cap cover](/lp/super-c-motorhome-fuel-cap-cover) page, or go straight to [Find My Fit](/find-my-fit) to see the exact door for your Super C. ## Frequently Asked Questions ### What is a Super C RV? A Super C RV is a motorhome built on a heavy-duty commercial truck chassis, such as the Ford F-550 or F-600, Freightliner S2RV, Ram 5500 or a Chevrolet/GMC medium-duty chassis. It keeps the cab-over look of a Class C but adds more power, more towing capacity and more cargo capacity. ### What is the difference between a Class C and a Super C motorhome? A standard Class C is usually built on a Ford E-350 or E-450 cutaway van chassis or a Chevrolet 3500/4500 chassis. A Super C uses a larger commercial truck chassis, most often with a diesel engine, so it can carry and tow much more. ### Who makes Super C motorhomes? Popular Super C models include the Dynamax Isata 5, Isata 6, Force HD and DX3, the Entegra Accolade XL and Esteem XL, the Jayco Seneca, the Thor Four Winds and Chateau Super C models, the Holiday Rambler Incline, the East to West Bravado and the Nexus Super C coaches. ### Are Super C fuel caps exposed? On most Super C motorhomes the diesel or gas fill and, on diesels, the DEF fill sit behind a simple fuel door or open on the side of the chassis, with no lock. Anyone can open them at a campground, storage lot or rest stop. ### How do I protect the fuel fill on a Super C RV? The RV Fuel Vault replaces the exposed fill area with a locking, theft-resistant steel fuel door that helps stop fuel theft, siphoning and tampering. Use Find My Fit to see the exact door for your year, make, model and chassis.