The AST Lowering Springs for BMW 4 420i/430i/420D (07/2020-) are engineered to provide a precise reduction in ride height while maintaining the driving comfort expected from OEM components. Manufactured using advanced cold-coiling technology on premium Wafios machines, these springs ensure consistent quality and durability. Designed specifically for the front and rear suspension, with a lowering of 40 mm each, they effectively lower the vehicle’s center of gravity, enhancing handling dynamics and stability without compromising everyday usability.
These springs offer a progressive spring rate, allowing for a smooth transition in suspension stiffness that balances performance improvements with ride comfort. The materials and manufacturing processes meet rigorous standards to guarantee longevity, supported by a lifetime warranty against breakage. This assurance reflects AST’s commitment to reliability and customer satisfaction.
AST Lowering Springs are a direct replacement for the original springs, tailored for the specific vehicle model. They provide a refined driving experience by reducing body roll and improving cornering response, making them suitable for both daily driving and spirited performance situations. Their compatibility extends across a wide range of vehicles, with precise engineering to fit the BMW 4 Series models specified.
Notes
- Not suitable for 4WD (four-wheel drive) cars.
- Approximately 10 mm less lowering for vehicles equipped with M-sport suspension.
- Approximately 10 mm less lowering for vehicles with Adaptive M-sport suspension.
Lowering Specifications
- Front lowering: 40 mm
- Rear lowering: 40 mm
- Progressive spring rate for balanced comfort and performance
- Cold-coiled using advanced Wafios machinery for precision and durability
- Lifetime warranty against breakage
Compatibility
- Designed specifically for BMW 4 Series 420i, 430i, and 420D models from 07/2020 onward
- Direct OEM spring replacement
- Not compatible with four-wheel drive vehicles
- Adjustments in lowering height for M-sport and Adaptive M-sport suspensions
Unless explicitly stated otherwise, all products sold by R44 Performance Limited are designated RACE ONLY and are solely for competition or off-road use limited to racing formally sanctioned by a recognized racing organization. Any other use, including recreational off-road use, may violate local, state, and Federal laws. R44 Performance Limited does not implicitly or explicitly confirm the legality of using any products it sells on public roads; that is entirely the responsibility of the consumer.
It is the responsibility of the customer to check with all federal, state local and environmental laws before ordering and installing a product. R44 Performance Limited is not responsible for any fees, fines or costs that a customer may incur as a result of failing to check with federal, state, local or environmental laws before ordering and installing a product.
We get a large number of custom orders and requests everyday, so as a result it is not always possible for us to keep every item in stock at all times in our warehouse. If you require the item urgently please contact our sales team here to check the stock before you make your purchase.
We totally understand if you're not certain a part will be compatible with your car, so we highly recommend contacting us here with your query. Our friendly sales team will then be in touch to confirm if this part is the correct part you are looking for.
All in stock products ship the same day if ordered before 2pm GMT
For out of stock items we will contact you with an estimated wait time if not otherwise specified above.
We offer worldwide shipping on all products. If upon receiving your product you wish to return; we offer a 30-day returns policy. For our in-depth returns information please follow the link. "R44 Returns Policy
All of our products come with a standard warranty of 1-3 years. This is dependant on the type of product however. For more details please see our warranty page here.
PLEASE NOTE
- Orders with both in-stock and backorder or out-of-stock products will be dispatched once all products are available to ship together.
- Contact our sales team if you want your parts fitted to your vehicle at our London workshop.
- Shipping estimates are based on courier delivery times and don't include time to despatch from our warehouse.