Heavy-duty rear replacement shock for 1996–2014 Spartan 240AR air suspension motorhomes. Fits K2, K3, and Mountain Master chassis. 46mm monotube with Comfitrac® piston. Cross pin upper / eyelet lower. Made in the USA.
The Bilstein 24-186780 B6 4600 Series Rear Shock Absorber is engineered specifically for Class A motorhomes on the Spartan Motors K Series and Mountain Master chassis equipped with 240AR air suspension. These are large, heavy coaches that demand a rear shock capable of handling sustained highway loads, managing the weight transfer of a fully loaded coach, and maintaining driver confidence mile after mile — without the harshness of a generic "heavy duty" replacement.
Bilstein's answer for premium motorhome chassis is the Comfitrac® working piston — a specialized design that reacts instantly to high-frequency road impacts like expansion joints and potholes, absorbing harshness before it reaches the coach and its occupants. The result is dramatically reduced body bounce, better rear stability under load, improved lane-change control, and the settled, planted feeling that distinguishes a properly damped Class A from one with worn or under-spec shocks.
Valved and calibrated specifically for the Spartan K Series 240AR air suspension chassis — not a generic heavy-duty shock
Bilstein's motorhome-specific piston instantly reacts to sudden road harshness for superior rear comfort and stability
Fade-free rear damping under sustained Class A motorhome loads — cooler and more consistent than twin-tube alternatives
Designed, engineered, and manufactured in the USA. Backed by Bilstein's limited lifetime warranty for the original purchaser
Air Suspension Requirement: This shock is designed specifically for Spartan K Series chassis equipped with the 240AR air suspension system. Verify your chassis has 240AR air suspension before ordering. Chassis Verification: This part fits the Spartan K2, K3, and Mountain Master chassis across specific year ranges. The K2, K3, and Mountain Master have different production year spans — see the fitment table below and verify your exact chassis model and year. Sold Individually: One shock absorber per package. Bilstein recommends replacing shocks in axle pairs for balanced handling and ride quality. Verify the number of rear shocks on your specific chassis configuration before ordering. Weight: At 20 lbs., this is a substantially heavier shock than standard light-truck applications — sized appropriately for Class A motorhome service.
In The Box (Qty: 1 Shock Absorber): • Bilstein 24-186780 Rear Shock Absorber • Blue Protective Boot • Black Rubber Bushings NOT Included: • Mounting Hardware (uses existing OEM hardware) • Additional shocks (sold individually — verify correct quantity for your chassis)
Bilstein recommends replacing motorhome shocks in axle pairs — both rear shocks together — to maintain balanced rear handling and consistent ride quality across the axle. Signs your Spartan motorhome rear shocks need replacement include: excessive rear bounce on rough roads, body sway during lane changes, rear-end "float" or porpoising at highway speeds, or uneven tire wear on the rear axle. At 20 lbs. each, these are heavy-duty motorhome-grade components. Use proper jack stands and safety equipment when servicing rear suspension on a Class A motorhome.
Bilstein Official Product Page Bilstein Technical Support: Website: www.bilstein.com Warranty: Limited Lifetime for original purchaser — B6 4600 series gas pressure shocks. Proof of purchase required. See full terms at Bilstein's website.
The 24-186780 fits the following Spartan Motors chassis with 240AR air suspension. Always verify your exact chassis model, year, and suspension configuration before ordering. Sold individually.
⚠️ Fitment cross-referenced across ShockWarehouse, SuperSteer Parts, Eurotek Tuning, and LM Performance. This shock requires the Spartan 240AR air suspension system. Year gaps exist within the K2 and K3 model ranges — verify your exact production year before ordering.