Bottom Line
A quality 4" TTB lift with radius arm drops, replacement coils, new shocks, and an alignment is the sweet spot for a capable, drivable full-size Bronco. It runs $1,200–$2,000 all-in with professional installation and gets you to 35" tires. The geometry investment is what separates a truck that drives well from one that wanders on the freeway.
Stock Suspension — What You're Starting With
The full-size Bronco is not a small truck. Clearances are reasonable from the factory, and 31" tires fit without modification. The stock suspension is not soft or inadequate — it is just optimized for on-road use, and it rewards any quality lift with meaningfully better off-road performance.
TTB Geometry — The Thing You Need to Understand
When you lift a TTB truck, the radius arms angle upward relative to their original geometry. This creates a caster change — the caster angle, which controls straight-line tracking and the steering wheel's ability to return to center, goes negative under lift. Negative caster produces a truck that wanders on the freeway, requires constant correction, and feels unstable at highway speeds.
Do Not Skip This
A 4" lift without radius arm drops on a TTB full-size Bronco will produce noticeable handling problems — wandering, vague steering, the truck not tracking straight on the highway. With properly installed radius arm drops and a fresh alignment, it is a livable setup. Without them, the lift will feel like a mistake.
The fix is radius arm drop brackets. These relocate the front pivot point of the radius arm downward, restoring closer-to-stock caster angle at the lifted height. This is not a premium add-on — it is a required part of any TTB lift above 2". Budget for it when planning the build.
Brands that make quality TTB radius arm drop brackets for full-size Bronco applications: Superlift, Rough Country, BDS. Expect $150–$300 for a quality bracket set. Installation is included in any competent lift install.
Lift Options by Height
Radius Arm Drop Brackets — More Detail
The most important single add-on for any TTB lift above 2". Here is what they do and why they matter.
In a stock TTB truck, the front radius arms run roughly parallel to the ground. The geometry is designed around that angle. When you lift the truck, the radius arms pivot upward at the rear (frame) mount — their front ends go up with the axle, their rear mounts stay fixed. The result is that the arms now angle upward from back to front. This changes the effective caster angle of the TTB beams, and the change is negative — it reduces self-centering and makes the truck want to wander.
Radius arm drop brackets move the rear pivot point of the radius arm downward, which restores closer-to-original arm angle at the lifted height. The caster angle comes back to something close to factory spec, and the truck handles predictably at highway speeds.
Installation requires removing the front radius arm from its frame bracket, installing the drop bracket, and reattaching. Not a complex procedure, but it requires the truck to be on a lift and the front suspension to be partially disassembled. Include it in any lift installation quote rather than treating it as a separate job.
Shock Selection
Shocks are not an afterthought on a lifted truck. The correct extended and compressed length is required to prevent binding at full articulation or bottoming at full compression. A shock that is too long will bind; a shock that is too short will bottom before the suspension does.
Any quality lift kit will specify shock dimensions. Do not mix and match shock lengths between different lift heights. And do not assume that stock-length shocks from a known-good brand will work on a lift they were not rated for.
- Bilstein 5100 series: The standard quality recommendation for street and moderate trail use on full-size Bronco. Monotube design, predictable performance, long service life. Available in lift-specific applications.
- Rancho RS9000XL: Adjustable damping (9 settings). A good option for a truck that sees both daily driving and occasional trail use — adjust softer for the road, firmer for the trail. More expensive than Bilstein 5100 but the adjustability is real.
- Fox 2.0: The premium option for a truck being built with off-road performance as the priority. Higher cost, higher performance on rough terrain.
Solid Axle Trucks (1978–1979)
Lifting a 1978–1979 solid axle Bronco is mechanically more predictable than lifting a TTB truck — there is no TTB geometry to correct, and the lift math is more conventional. Leaf spring lift packs and quality shocks are the standard approach for most builds in this range.
Caster is still a consideration after lift on solid axle trucks — the solid axle pivots on the radius arms in a similar geometry — verify the alignment after any lift and address caster if needed with adjustable upper links or shims. A spring-over axle conversion (SOA) is the extreme option for serious off-road clearance; that is a fabrication project, not a bolt-on.
Most 1978–1979 builds stay under 4" with spring-over as the outlier option. The solid axle architecture makes this generation the more capable off-road platform regardless of lift height.