UMI Performance 1982-2003 S10/S15 Lower A-Arms, Coilover Only, Competition

UMI Performance

Regular price $799.99

UMI’s 3057-1 lower a-arms arms feature a relocated ball joint cup which offers 10 degrees caster when used with our P/N 3056 upper arm while keeping the spindle pin centered. The 3/4” taller Howe ball joint works to optimize the roll center, lower the center of gravity and lowers the ride height ½”. The double shear shock mount is removable which permits spring and shock changes at the track in minutes without disconnecting the ball joints. An aluminum steering stop is adjustable and limits steering lock to prevent tire and wheel damage. UMI designed Delrin bushings help the 3057-1 travel smoothly for bind-free operation whether running street, strip, road race or auto-x. Also included is a double shear sway bar mounting system which accepts UMI sway bars and many other manufacturers stock location aftermarket units. Available in UMI red or black powder coat. 100% designed, manufactured and raced with pride in the USA. Battle tested on the iconic UMI Green Machine

Performance note: UMI recommends adding the P/N 3060 bump steer kit for optimal performance. Lower a-arms work best when used in conjunction with caster corrected upper a-arms.


  • 1-¼” and 1-½” USA DOM tubing construction.
  • CNC laser cut components throughout.
  • 10 degrees caster potential when combined with UMI 3056 upper a-arm.
  • Removable double shear mount to allow spring/shock replacement without removing spindle.
  • Mount spacing suitable for Afco, Viking, Ridetech and many other aftermarket manufacturers shock/spring combos.
  • Adjustable steering stop.
  • Double shear swivel sway bar mounts and hardware work with UMI P/N 3035 and most other factory eyelet style sway bars.
  • Smooth travel Delrin bushings, UMI designed and machined.
  • Saves 3.2lbs per set as compared to stock stamped a-arms.
  • Suitable for competition use. Road race, auto-x, drag race, street corner carving.
  • Designed, tested, manufactured and raced in Philipsburg, PA-USA.
  • Our choice on the UMI Green Machine.

Installation Notes: The 3057-1 is a versatile competition a-arm that can be used with the following springs and shocks:

1. Hybrid coilover kits A224-XXXR and A204-XXXR can be used with no modifications required to the car. The top of the spring fits in the original G-body spring locator in the upper frame. A204 poly bushing coilover kits require bearing kit P/N SSB10T-APK. A224 bearing mounted coilover kits require 2 of sleeve P/N 9556-103. UMI can supply this style shock as ready to install as well. Hybrid coilover spring rates are available up to 650lb.

2. 3058-650 or 3058-850 can be used with trimming to the upper spring locator. Trimming can be accomplished with a torch or slicing wheel. Once trimmed, the benefit of this style hybrid is the fact that there are a vast number of spring lengths and rates available.

3. Coming soon will be a full racing coilover which requires major construction in the upper spring pocket area.

4. The 3057 cannot be used with standard size coil springs and stock mount shocks.