4Wheel Underground, llc

Engineered Performance
Suspension Systems

Laser cut & precision welded Brackets

For optimal performance, our design maintains the vehicle’s caster throughout wheel-travel. Paired with our tuned Radflo coil-overs, it ensures steady handling across all terrains.

Custom Tuned Radflo coilovers

The result is a smooth high-speed ride with great bump control and agile street handling. If you think coil-overs are always sloppy, you haven’t experienced them tuned right.

Summit Machine Joints

The Summit Machine Large Flex Joint is our top-selling joint. Designed for builders seeking quality, it’s a rebuildable spherical joint that consistently delivers on performance and longevity, with some lasting up to 100,000 miles.

Sharp Steering

For optimal performance, our design maintains the vehicle’s caster throughout wheel-travel. Paired with our tuned Radflo coil-overs, it ensures steady handling across all terrains.

Tough Subframe

High quality materials mixed with top tier fabrication and years of real world experience equal best in class subframe armor and components.

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Cant decide on just one category? Just browse the whole catalog.

Quality Designed & Built

“A quality designed and built suspension system should do more than just flex over rocks. It should provide the user with great performance both on and off-road. We believe that with enough research and testing, the correct components will equal predictable handling in all situations providing the user with the satisfaction one expects from a performance suspension system.”

Brian Osborne, founder of 4WU