Swift Springs Expands 3.5" ID Bulletproof Spring Line with New 115 lb/in Rate

Swift Springs continues to expand its premium 3.5-inch ID Bulletproof (BP) Spring lineup with the introduction of the new 180-350-115 BP. Featuring an 18-inch free length and 115 lb/in spring rate, this latest addition gives racers another valuable tuning option while delivering the durability, consistency, and performance that have made Swift's Bulletproof series a trusted choice in motorsports.

Designed with the same engineering philosophy as the rest of the Bulletproof lineup, the new 115 lb/in spring provides racers with additional flexibility when fine-tuning chassis balance for varying track conditions and suspension setups.

Engineered from the Material Up

Unlike many spring manufacturers, Swift Springs is also a metallurgy company, developing and producing its own proprietary spring materials in-house. The new 180-350-115 BP is manufactured using Swift's exclusive HS5.TW material in Japan, giving the company complete control over the engineering and manufacturing process from raw material to finished product.

This vertically integrated approach allows Swift to produce springs that deliver exceptional consistency, durability, and repeatable performance—giving racers confidence that every spring performs exactly as intended.

Designed for Maximum Performance

The new 115 lb/in Bulletproof Spring incorporates the same proven engineering features found throughout the BP lineup, including:

• Bulletproof spring design engineered for long-term durability
• Proprietary HS5.TW spring material manufactured in-house
• Coil bind technology for high-performance racing applications
• Full linear spring characteristics throughout the usable stroke
• Faster suspension response compared to conventional spring designs

These engineering advantages help racers achieve more predictable chassis behavior, improved suspension consistency, and greater confidence when making setup adjustments throughout the season.

Expanding Tuning Flexibility

Adding a 115 lb/in rate to the existing 3.5-inch ID Bulletproof series gives racers another option when searching for the ideal suspension setup. Whether adapting to changing track conditions or refining chassis balance, having additional spring rate choices allows teams to make more precise tuning decisions.

As with every Swift spring, the goal is to provide racers with products engineered to perform at the highest levels of competition.

Available Now

The new 180-350-115 BP 18-inch x 3.5-inch ID Bulletproof Spring is in stock now and shipping to authorized Swift Springs dealers.

Swift Springs remains committed to pushing suspension technology forward through continuous innovation, advanced metallurgy, and racer-driven product development. By engineering both the material and the spring, Swift continues to provide competitors with the tuning advantages needed to stay at the front of the field.