4-Inch Lift Kits: Compare the Complete System, Not Just the Height

Four inches is often where system architecture becomes more important

Many current 4-inch applications are no longer just a spacer or simple front-height change. They can include crossmembers, differential relocation, steering knuckles, skid plates, sway-bar drops, upper control arms, rear blocks or application-specific shock options. The exact hardware varies by platform, but the common theme is that geometry correction becomes a larger part of the package.

That makes a 4-inch page useful only if it stays vehicle-specific. A BDS F-150 4-inch system, a Ram 1500 air-ride 4-inch system and a ReadyLIFT GM 1500 4-inch SST are not interchangeable ways to achieve the same number.

Representative 4-inch systems we track

Factory suspension can split the same vehicle into different kits

Ram 1500 is a good example. BDS publishes a standard 4-inch 2019–2024 application and a separate 4-inch system for trucks with factory rear air ride. On GM 1500 trucks, some BDS applications separate Adaptive Ride Control from standard suspension, while ReadyLIFT's current 69-39400 is designed to work with or without ARC but excludes Trail Boss, ZR2, AT4 and AT4X.

The lesson is not that one brand handles the feature “better.” It is that the factory suspension setup must be known before choosing a 4-inch kit.

Wheel and tire clearance remains kit-specific

BDS publishes up-to-35-inch guidance for several current 4-inch half-ton systems, but the permitted wheel width and backspacing still vary by application. ReadyLIFT's GM 1500 69-39400 publishes different maximum tire guidance for 2019–2022 Chevy versus GMC and later Chevy applications because the surrounding body/wheel-well conditions differ.

That is why Lift Kit Match will never convert “4 inches” into a universal “fits 35s” rule. Use the wheel/tire combination attached to the exact product and exact vehicle.

Installation may be more involved than the advertised height suggests

Many 4-inch crossmember systems correct front suspension and steering geometry through relocated mounting points and new knuckles. Others, such as ReadyLIFT's GM SST approach, use a different mix of strut extensions, preload spacers, upper control arms and rear blocks. The resulting install work, reversibility and service considerations can be quite different even when the front lift number is the same.

Compare the exact installation instructions before choosing between a 3-inch, 4-inch and 6-inch system.

Shopping paths after fit is confirmed

The vehicle-specific shopping routes below are broad search paths, not proof of fit. Use them only after the truck's exact suspension and vehicle configuration are known.

Manufacturer sources checked

• BDS 4-inch F-150 4WD (2021–2026)Current crossmember-style F-150 system with rear-lift/shock choices and tire guidance.
• BDS 4-inch Ram 1500 (2019–2024)Current standard-suspension Ram system and 22-inch-wheel knuckle note.
• BDS 4-inch Ram 1500 with air rideDedicated factory-air-suspension application.
• ReadyLIFT 69-39400 4-inch GM 1500 SSTCurrent ARC/non-ARC support, factory-package exclusions and tire/wheel guidance.
• BDS 4-inch Tacoma (2016–2023)Current Tacoma 4WD system with published tire guidance.