UMI Performance AB4250-1 Double Adjustable Coilover Shock & Spring Lowering Kit

The UMI Performance AB4250-1 is a complete shock and spring lowering kit built around four Viking double adjustable shocks paired with a hybrid front coilover spring system and your choice of 1 or 2-inch rear lowering springs. Designed for the street, strip, or autocross, this bolt-in kit delivers improved handling and a aggressive lowered stance without requiring welding or a spring compressor.

Key Features:

• 0–3" front lowering range via adjustable coilover front shock with easy height lock
• 1" or 2" rear drop available with included rear lowering springs
• Four Viking double adjustable shocks hand-built in Lakeville, Minnesota — 19 independent compression and 19 rebound settings (361 total combinations)
• Tune without tools — switch between street, strip, and corner carving at the turn of a knob
• Baseline shock settings: 6C/8R all-around street | 10C/12R corner carving | 6C/2R front + 6C/6R rear for strip
• Premium Made-in-USA springs — shot peened and coated for long-term durability
• Lowers center of gravity and improves upper A-arm geometry for better handling balance
• 100% bolt-in installation — no welding, no spring compressor required

Front Spring Rate Options:

• 250 lb — 11" tall, drag race only; serious weight reduction required
• 350 lb — Small block cruise or drag race; some weight reduction required
• 450 lb — Small block cruising or big block drag race applications
• 550 lb — Small block performance handling; all big block applications except drag

Kit Includes:

• (2) Front coilover shocks, double adjustable
• (2) Rear shocks, double adjustable
• (2) Front springs (choice of 250, 350, 450, or 550 lb rate)
• (2) Rear springs (choice of 1" or 2" drop)

Optional Spanner Wrench & Thrust Bearing Kit: The spanner wrench allows front ride height adjustment while the shock remains mounted on the vehicle. The thrust bearing kit fits between the spring and spring seat, allowing the seat to rotate on a bearing for smoother, easier ride height changes. This accessory is strongly recommended but not required to complete the installation.