4.0" Long Arm SRS Suspension SystemThe 4.0" long arm system is a complete replacement suspension. Able to handle tires up to 35" tall, it utilizes a 4-link front axle mounting configuration for a true and correct caster curve, and improved anti-dive geometry throughout the entire range of linear wheel travel - just like the factory does it. Other systems using radius arms, medium length arms called "long arms" and the rest, can't match it's performance.Utilizing a true long arm rear 4-link, the rear axle is attached to the frame by 4 pivoting links- just like the factory does it. The result, is incredible linear wheel travel and axle articulation, improved anti-squat geometry for better hill climbing performance, and a free, no-binding movement that short arm or radius arm systems can't deliver.Do you drive your JK daily? Modifying it doesn't mean that it can't ride better than stock. This system offers hard core Rock-crawling performance and rides and steers BETTER than stock. Don't believe the hype about radius arms, the arguments being offered are more confusing than revealing. The factory uses a 4 link configuration for several important reasons. Added strength and safety, reduced binding and bushing wear, and incomparable differences in both on and off road driving performance are the proof of this method. Full-Traction has taken the factory 4 link configuration to its limits by adding arm length and geometry corrections to compensate for height, and use in critical off road conditions.No other system available offers this configuration.You want tough? All components in this suspension system are built for maximum off-road punishment. We use 2" x .250" wall DOM tubing for our lower trailing arm assemblies for serious rock dragging, and 1/4" plate laser crafted bracketry throughout. This is a FULLY BOLT-ON system. No welding is required to install. When we say "perfected" we mean that in every possible way. Full-Traction just spoiled the competition's day.