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Super C Diesel Buyer’s Guide: Freightliner S2RV and Ram 5500 Models Compared

10 min readOctober 2026
Super C Diesel Buyer’s Guide: Freightliner S2RV and Ram 5500 Models Compared

Super C Motorhomes Beyond the Ford F-550


Most Super C motorhomes ride on the Ford F-550 or F-600, which we covered in our F-550/F-600 buyer’s guide. Two other diesel chassis matter if you’re shopping this segment:


  • Freightliner S2RV, a medium-duty truck chassis under the largest Super C coaches, with a Cummins diesel.
  • Ram 5500, a heavy-duty chassis cab with the Cummins 6.7L diesel, used by Dynamax for its Isata Super C models.

    • Both are diesels with DEF systems, both tow well, and both have a fuel fill with no locking door from the factory.


    Watch Out for Similar Names


    Several brands sell a big Super C on the Freightliner and a smaller one on the Ford F-550 under nearly the same name. Check the chassis before you compare prices or order parts:


  • Jayco Seneca is on the Freightliner S2RV, while the Seneca XT is on the Ford F-550/F-600.
  • Entegra Accolade and Accolade XL are on the Freightliner S2RV, while the Accolade XT is on the Ford F-550/F-600.
  • Dynamax Isata 5 and Isata 6 are on the Ram 5500, while the Europa S is on the Freightliner S2RV.

    • Freightliner S2RV Builders and Models


  • Jayco: Seneca (37K, 37L, 37M, 37TS, 37RB, 37FS) and Seneca Prestige
  • Entegra Coach: Accolade and Accolade XL
  • Thor Motor Coach: Inception and Pasadena
  • Tiffin: Allegro Bay (34DB, 38AB, 38BB, 38EB)
  • Newmar: Grand Star (3444, 3940, 3948)
  • Dynamax: Europa S
  • Renegade: Valencia (35MB, 38BB, 38RB)
  • Nexus RV: Wraith (30F through 37F)

    • These are the biggest Super C coaches, often around 35 to 40 feet, with heavy towing capacity and an air-brake medium-duty chassis. They need more parking space and a chassis service center that works on medium-duty trucks.


    Ram 5500 Builders and Models


    Dynamax builds its Isata 5 (28SS, 30FW, 34DS) and Isata 6 (30FW, 31KS, 32KS) on the Ram 5500. They are shorter than most Freightliner coaches, easier to drive and park, and any Ram dealer can service the chassis.


    What to Compare When You Shop


  • Length and parking. A 38-foot Freightliner coach and a 30-foot Isata drive very differently.
  • Brakes and service. Medium-duty chassis may use air brakes and need truck service centers. The Ram uses hydraulic brakes and is serviced at Ram dealers.
  • Towing. Both chassis tow well. Check the coach’s hitch rating, not just the chassis.
  • DEF. Both are diesel with a DEF tank, which is a second fill point to protect. See our post on DEF theft and contamination.

    • How to Lock Down the Fuel Fill


    Neither chassis comes with a locking fuel door. Diesel is expensive and Super Cs often sit at campgrounds and storage lots, which makes them a target for siphoning and tank contamination.


    Here’s what our fitment database lists for The RV Fuel Vault™:


  • Dynamax Isata 5 (Ram 5500): RVFV-1001S Small Standard Single, $159.95 pre-order
  • Dynamax Isata 6, 2017–2026 (Ram 5500): RVFV-2001S Small Standard 2-Pack, $319.95 pre-order
  • Dynamax Isata 6, 2027–2028 (Ram 5500): RVFV-30012S1R pack with 2 small doors and 1 round door, $479.95 pre-order
  • Freightliner S2RV coaches: RVFV-1002L Large Standard Single, $169.95 pre-order. Fit is confirmed on the Nexus Wraith. For the other S2RV coaches listed above, the fit is inferred from the chassis and still being confirmed, so send us a photo of your fuel fill before you order.

    • Check your coach in Find My Fit → | Pre-order →


    Other Chassis Guides


  • Super C: Ford F-550/F-600
  • Class C: Ford E-350 and E-450
  • Class A gas: Ford F53 and Workhorse
  • Class C and Super C: Chevrolet and GMC

    • Questions? Call 941-732-0452.

    Freightliner S2RV motorhomeRam 5500 Super CSuper C diesel buyers guideJayco Seneca vs Entegra AccoladeDynamax Isata 6Super C locking fuel door

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