King Shocks SPR3-12-300 3.0" ID 12"300 lb/in Coilover Spring Blue for 2.5"Shocks

Vehicle Fitment

• Universal - fits all coilover shock absorbers with a 2.5" outside diameter body and a 3.0" spring perch seat. Compatible with King Shocks 2.5" coilovers and all other brands of 2.5" OD coilover shocks accepting a 3.0" ID spring.
• Verify the spring seat diameter and required free length on your specific shock before ordering. This spring has a 3.0" inside diameter, 12" free length, and 300 lb/in rate.

Fitment Notes

• The SPR3-12-300 is a 3.0" ID coilover spring designed for use on 2.5" outside diameter shock bodies. It is not compatible with 2.0" body shocks (which use the 2.5" ID SPR25 series) or 3.0" body shocks (which use the 3.75" ID SPR375 series). Confirm your shock body diameter before ordering.
• At 12" free length and 300 lb/in, this spring is suited for use as the tender (helper) spring in a dual-rate coilover configuration on 2.5" body shocks - providing slightly stiffer initial compliance than the 250 lb/in SPR3-12-250 before the primary spring engages. It is also appropriate as a single-rate primary spring in applications requiring a moderate, linear rate at this length.
• Spring selection requires matching free length, rate, and ID to both the shock travel and the vehicle's suspension geometry, weight, and intended use. Consult your suspension builder or King Shocks directly to confirm this spring is correct for your specific configuration.
• Sold individually - one spring per order. Most coilover applications require two or more springs per build; order the quantity needed.
• The spring rate of 300 lb/in is etched directly into the top coil for clear identification after installation and hard use.

Features

• 300 lb/in linear spring rate - a moderate, versatile rate suitable for use as a stiffer tender spring in dual-rate configurations on 2.5" body shocks, or as a single-rate primary spring on lighter applications requiring a moderate linear rate; steps up from the 250 lb/in SPR3-12-250 for builds where slightly more initial resistance is needed before the primary spring loads
• 12" free length - a short spring length well suited to dual-rate setups as the tender/helper spring positioned above the primary coil on long-travel 2.5" body shocks, where it controls initial suspension movement and provides a progressive transition into the primary spring's rate
• Wound specifically for off-road applications from the ground up - not repackaged automotive or industrial springs. King designs spring rate, wire diameter, and coil geometry exclusively for off-road suspension use, validated through real-world competition testing from Baja to Dakar
• High-tensile chrome silicon wire - the highest grade spring wire material, providing superior tensile strength, fatigue resistance, and rate retention under the repeated high-amplitude suspension cycles of off-road competition use
• Closed and ground ends - both ends are precision ground flat for square, stable seating on spring perches without rocking, cocking, or producing lateral side loads on the shock shaft; critical for consistent spring behavior and long shock seal life
• Blue powdercoat finish - provides corrosion resistance and visual identification within King's color-coded spring lineup; durable against rock chips, trail debris, mud, and UV exposure in off-road environments
• Spring rate etched on top coil - permanently etched into the metal before powdercoat, remaining legible after installation and hard field use for rate confirmation without spring removal
• Compatible with King Shocks and all other brands of 2.5" OD coilover shocks - the SPR3 series is a universal spring line
• Made in USA - manufactured to King Shocks' specifications using domestic production
• Lifetime warranty against sagging and breakage - King covers these springs for life to the original purchaser; in the rare event of failure, replacement is provided with no questions asked

Specifications

• Part Number: SPR3-12-300
• Brand: King Shocks
• Spring Type: Coilover (Single Rate, Linear)
• Spring Rate: 300 lb/in
• Inside Diameter (ID): 3.0" (76.20mm)
• Compatible Shock Body OD: 2.5"
• Free Length: 12" (304.80mm)
• Wire Material: High-Tensile Chrome Silicon
• End Type: Closed and Ground
• Finish: Blue Powdercoat
• Rate Identification: Etched on top coil
• Fitment: Universal - King and all brands of 2.5" OD coilover shocks
• Quantity: Sold individually (1 spring per order)
• Made in USA
• Warranty: Lifetime against sagging and breakage

Included Components

• 1x King Shocks 3.0" ID x 12" x 300 lb/in Coilover Spring (Blue Powdercoat)

Product Description

The King Shocks SPR3-12-300 is a 3.0" inside diameter, 12" free length, 300 lb/in linear coilover spring for use on 2.5" outside diameter shock bodies. It is a universal spring compatible with King Shocks 2.5" coilovers and all other brands of 2.5" OD coilover shocks that accept a 3.0" ID spring. Sold individually. Made in USA. Lifetime warranty against sagging and breakage.

The 300 lb/in rate and 12" free length make this spring well suited as a tender (helper) spring in dual-rate coilover configurations on long-travel 2.5" body shocks, providing slightly firmer initial compliance than the 250 lb/in SPR3-12-250 before the stiffer primary spring engages. In a dual-rate setup, the tender spring controls the suspension's initial response to small terrain inputs while the primary spring handles larger suspension events - the combination produces a progressive, non-linear rate curve from two linear springs. The 300 lb/in rate is also appropriate as a single-rate primary spring in lighter-load applications where a moderate linear rate at 12" is the correct configuration.

Like all King coilover springs, the SPR3-12-300 is wound from high-tensile chrome silicon wire developed specifically for off-road use - not repurposed from automotive or industrial spring stock. Spring rate, wire diameter, and coil geometry are validated through King's real-world competition testing program. Closed and ground ends ensure flat, square seating, and the rate is permanently etched into the top coil for field identification after installation.