These are the most basic type of springs found in modern vehicles on the road today. These are the same springs that modern Jeeps come equipped with from the factory. It is also among the cheapest options in terms of replacement or upgrade. They offer a consist entry level of performance and in most cases enough for your application. Entry-level suspension lifts, including leveling kits, use linear springs because they are inexpensive to produce. Dialing in a specific coil rate, during manufacturing, ensures a constant level of ride firmness. A linear spring works by completely compressing in an even rate throughout the length of the spring.
As a result the ride firmness is consistent and the same, no matter the speed or conditions. For off-road use, one of the main drawbacks with linear springs is suspension travel. The overall length of a linear spring is smaller than other options. This limits the amount of travel/articulation while a Wrangler is capable of off road. Another major drawback with linear springs is “Sagging”, this is when the spring, through time and use, becomes fatigued and over-worked. It can no longer sustain the same level of height and slowly loses its firmness, resulting in loss of height and performance. Linear springs are also very difficult to estimate lift height because of the effects of weight and pressure being applied by the vehicle. Manufacturers often provide a “Fully Loaded” weight estimate when assigning a number to lift kits. These estimates can increase tremendously with linear springs. Suddenly an estimated 2.5” lift can turn into a 4.5” actual lift on an otherwise stock Wrangler. These wild variables make it difficult to properly adjust the Wranglers suspension geometry and could lead to problems with handling and driveshaft rubbing.