When air spring suspension performance matters, the BILSTEIN 40-221601 delivers — built to the same dimensional and material standards as the original part it replaces. The part is built to the following specification: Fitting Position: Rear Left, Spring Design: 20, paired article number: 40-221618. Each dimension is checked against the OEM reference to ensure the component seats and functions correctly first time. Compatible with BMW vehicles; use the vehicle selector above to confirm exact fitment for your make, model, and engine variant. Fitment data is sourced from TecDoc, the authoritative European parts catalogue. This part supersedes original equipment references: 1 095 579, 37 12 1 095 579, 37 12 6 750 355, 6 750 355 and 1 more. Matching these numbers confirms a like-for-like replacement with no loss of function. BILSTEIN is a recognised supplier of automotive suspension components to independent workshops and dealer networks across Europe. All parts are sourced from authorised distribution channels and carry full manufacturer traceability — you receive exactly the same component supplied to professional garages and dealer workshops. If fitment or specifications do not match your vehicle, our technical team can help identify the correct alternative — use the vehicle selector or contact us with your VIN for a guaranteed-fit recommendation. Replacing worn components on schedule preserves your vehicle's safety, reliability, and resale value — and aftermarket parts from established brands deliver OEM-equivalent performance at a fraction of the dealer price. Every part is dispatched from our UK warehouse with a 30-day money-back guarantee and free hassle-free returns.

BILSTEIN, founded in 1873 in Ennepetal, Germany, is a premium manufacturer of monotube shock absorbers and suspension components, part of thyssenkrupp. BILSTEIN specialises in high-performance gas-pressure shock absorbers, coilovers, lift kits, and electronic damping systems. As the OE suspension supplier to BMW, Mercedes-AMG, Porsche, and Ford Performance, BILSTEIN represents the highest tier of damping technology. From professional motorsport to luxury touring, BILSTEIN delivers superior handling, comfort, and durability that discerning drivers and performance enthusiasts demand.