Allstar Performance ALL64232 12" Spring Pre-Loader - Heavy Duty Suspension Upgrade for Racing & Off-Road Vehicles - Perfect for Track Days, Baja Racing & 4x4 Trucks

Pre-Loaded allows use of a softer spring rate that is "pre-loaded" at ride height. The pre-loaded spring will have less rate increase as the suspension travels. For example, a 150 lb./in spring can be pre-loaded to 400 lbs. At ride height, but still only increases at a rate of 150 lb./in as suspension travels. The entire unit may also be exchanged with another unit with a different rate spring pre-installed to allow spring rate changes without affecting ride height. Commonly used on the rear Coil-overs, pre-loaded requires 3" I.D. Spring, includes a thrust bearing set and fits most shocks. Note: unit is typically installed with slotted inner half towards the shock body. Always check components for possible interference.