Upper Control Arm Toyota Prado 120/150s, FJ Cruiser 50mm When an IFS vehicle is fitted with a suspension lift, the original caster and camber specifications are pushed outside the acceptable limit. The vehicle loses caster which makes the steering vague, and positive camber is introduced, which contributes to uneven and accelerated tyre wear. Tough Dog Upper Control arms can help get the maximum performance and lifespan from your suspension and steering components.