TEIN VSTD2-D1AS3 Flex A Coilover Kit with Hydraulic Bump Stopper

The TEIN VSTD2-D1AS3 Flex A coilover kit represents an advanced suspension solution engineered for the perfect balance between street comfort and performance handling. This complete coilover system features TEIN's innovative Hydraulic Bump Stopper (H.B.S.) technology, proven effective in World Rally Championship and European Rally Championship competition, now adapted for comfortable daily driving.

Hydraulic Bump Stopper Technology:

The H.B.S. system is mounted internally within the shock absorber and generates precise damping force at or near full-bump compression. Unlike traditional urethane or rubber bump stops that create harsh jolts and rebound, the hydraulic system converts impact energy into thermal energy, absorbing large impacts smoothly. This provides exceptional comfort even when the vehicle is fully loaded with passengers or cargo, while protecting the dampers from damage during full stroke compression.

Key Specifications:

• Front spring rate: 4.0K (39.2mm)
• Rear spring rate: 5.0K (48.6mm)
• Front ride height adjustment: -71mm to -20mm (recommended -50mm to -30mm)
• Rear ride height adjustment: -73mm to -19mm (recommended -45mm to -25mm)
• 16-way damping adjustment (simultaneous compression and rebound)
• Full-length adjustable via threaded body and spring seat locks
• Reinforced rubber upper mounts front and rear
• Twin tube internal construction for strength and comfort
• 22mm outer diameter piston for strut type applications

Premium Construction and Durability:

Upper mounts and lower brackets feature TEIN's signature green powder coating with a patented 2-layer/1-bake treatment for superior corrosion resistance. The shell case is protected by TEIN's proprietary ZT Coating, providing exceptional resistance to stone chips and rust. High-rigidity STKM13C steel construction ensures long-lasting performance. Strut-type applications utilize sufficiently thick ribbed plates for knuckle brackets, with flange-shaped edges that increase contact area and prevent bracket loosening.

Advanced Features:

• Incorporated advance needle design (nearly 200% improvement over earlier lineups)
• New damper valving specifications optimized for improved street comfort
• EDFC (Electronic Damping Force Controller) and EDFC Active compatible
• Complete kit includes upper mounts

This coilover system is manufactured by TEIN in Japan using high-quality materials and precision engineering. The Flex A series is ideal for enthusiasts seeking a comfortable daily driver with the capability for spirited driving when desired. Note that front damping force adjustment requires shock absorber removal, and EDFC installation is recommended for convenient adjustment.