ARB Old Man Emu UCA — Proper Geometry for Your Lifted Tacoma, Land Cruiser & GX 550
The ARB Old Man Emu Upper Control Arm (UCA0021) is the suspension geometry fix for the 2024+ Toyota Tacoma, Land Cruiser LC250, and Lexus GX 550. Upper control arms live between the vehicle frame and the knuckle spindle — when your vehicle is lifted, the factory UCA geometry falls out of spec and pulls the caster angle out of the acceptable range. Symptoms include vague steering, reduced high-speed stability, and uneven tire wear. The ARB OME UCA corrects that geometry, restoring proper caster and giving your lifted build the handling it should have.
Construction
Tubular steel construction with forged eyelet and ball joint housings
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Tubular steel body — stronger than the factory stamped arm without the weight penalty of solid billet
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Forged eyelet and ball joint housings — not welded fabrication; forged housings provide consistent material density and superior strength at the critical stress points
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GIIRO bushing — free-pivoting, grease and maintenance-free. No zerk fitting to forget about, no degradation from missed service intervals.
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Heavy-duty greaseable ball joint — serviceable with a protective cap for trail and off-road durability
ARB OME UCA0021 installed — correct geometry, increased tire clearance
GIIRO Bushing — What It Is
GIIRO bushing and greaseable ball joint detail
The GIIRO (Grease Independent Inner Ring Oscillation) bushing is ARB/OME's proprietary bushing design. Traditional rubber or polyurethane bushings require periodic lubrication and degrade over time with heat and UV exposure. The GIIRO bushing is self-lubricating and maintenance-free — it pivots freely without binding and doesn't require greasing to maintain performance.
ARB OME UCA0021 tubular construction detail
Specifications
- Part number: UCA0021
- Material: Steel (tubular body, forged housings)
- Color: Black
- Bushing: GIIRO — free-pivoting, maintenance-free
- Ball joint: Heavy-duty, greaseable with protective cap
- Prop 65: No
- Warranty: 3 years
Fitment
Fits: 2024+ Toyota Tacoma (all trims, Gas and Hybrid) • 2024+ Toyota Land Cruiser LC250 (all trims) • 2024+ Lexus GX 550 (Luxury and Premium trims). Wheel alignment required after installation. Check fender clearance when running aftermarket tires and wheels.
FAQ
Why do I need a UCA when I lift?
The factory upper control arm is designed for the OEM ride height. When you lift, the caster angle changes — the factory arm can't compensate. An aftermarket UCA like this one is designed with corrected geometry so your caster stays in spec at your lifted height, maintaining proper steering feel, stability, and tire wear.
What is the GIIRO bushing and why does it matter?
GIIRO (Grease Independent Inner Ring Oscillation) is ARB/OME's maintenance-free bushing design. It pivots freely without requiring grease or periodic service. Unlike rubber or poly bushings that can dry out and bind, the GIIRO maintains consistent performance without maintenance.
Does the ball joint need to be greased?
The ball joint (not the bushing) is greaseable with a standard zerk fitting and includes a protective cap. The bushing itself is maintenance-free. Service the ball joint periodically, especially if you use the vehicle heavily off-road.
Is a wheel alignment required?
Yes — a wheel alignment is required after installing any aftermarket UCA. Budget for this as part of your installation cost.
Should I check fender clearance?
Yes — when running aftermarket tires and/or wheels, check that you have adequate clearance between the tire and the arm and fender liner through the full range of suspension travel before hitting the trail.
Does this fit the Tacoma Hybrid?
Yes — fitment covers both gas and hybrid Tacoma trims for 2024.
