Never settle.

You’ve worked hard and earned the ability to explore new places and meet new people on your time. We’re here to make sure your journey is safe, smooth, and always first class. Entegra Coach and Spartan RV Chassis partner to be co-pilots on the adventure of a lifetime.

Entegra’s Cornerstone is built on the 45’ Spartan K3 605 chassis. Designed, engineered, and made in America with the finest components creating a premier foundation for the most discerning RV makers and owners.

Spartan RV Chassis makes the only chassis built exclusively for motorhomes. We didn’t take the easy route and modify a heavy truck chassis for our partners at Entegra. We knew they wanted an unmatched ride and uncompromising durability that was as smooth and quiet as it was safe and well-appointed. So, we built them the unique K3 605 chassis from the ground up. The highest-quality materials provide reliability and dependability, and constant innovation means you’re safe & secure. Spartan Chassis provides a comfortable customer experience, nationwide service, and the best warranty in the business.

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Premium Features

  • E-Z Steer for a smoother driver experience and reduced driver fatigue
  • Power tilt & telescoping steering column
  • Independent front suspension
  • Electronic suspension control system with self-leveling feature, including air compressor for extended stays
  • Automatic heated moisture ejectors with color-coded lanyards
  • Side-mounted service center
  • Connected Coach™ digital dash with 15" display
  • Passive steer tag axle
  • 3-stage engine compression brake
  • 20,000-lb. towing capacity
  • SMART steering wheel
  • Steering wheel mounted controls for radio & phone
  • Spartan Passive Keyless Start
  • Suspended adjustable pedals
  • Air disc brakes at all wheel positions
  • Hands-free phone controls
  • K3 605 Chassis



Peak HP

605 hp @ 1,800 RPM



Towing Capacity

20,000 lb


3-year/50,000 mile

Safety Innovations

Spartan Advanced Protection System – Cornerstone

Spartan Advanced Protection System® is the industry’s first and only comprehensive safety system engineered to keep your Entegra Cornerstone coach on the road, and safe… to enjoy every adventure.

  • OnGuardACTIVE, Collision Mitigation with Adaptive Cruise Control alerts the driver of potentially dangerous driving scenarios and adjusts speed to maintain a safe following distance.
  • Electronic Stability Control (ESC) helps the driver maintain control of the coach in extreme steering manuevers by automatically controlling individual brakes to help keep the coach moving in intended direction.
  • Spartan Safe Haul™ The industry’s only factory-chassis integrated air supply for tow vehicle brake systems.
  • Automatic Traction Control (ATC) helps the driver maintain traction under the drive axle tires in slippery conditions by automatically applying brakes on the wheel end that is slipping. This helps transfer power to the wheel end with more traction.
  • Tire Pressure Monitoring System (TPMS) displays tire pressure and temperature for  individual tires. The system will alert the driver if any tire pressure or temperature exceeds set thresholds. The system is expandable to monitor towed vehicles as well.
  • Connected Coach


Spartan Connected Coach


Parts Manuals

Operators Guides

Service Guides

Service Manuals

Wiring Manuals

Alternative Fuels


Ford Transit

RAM ProMaster