When coil sprung, live axle vehicles are lifted the caster angle is changed (see diagram). This can lead to vagueness and a lack of self-centering of the steering. Fitting 3-degree caster corrected radius arms re introduces positive caster angle to return the steering to the correct geometry on vehicles lifted 2-3" (50-75mm), for vehicles lifted more than 2-3" 6 degree caster corrected radius arms should be used. The TF508 and TF528 radius arms are designed to accept the 44mm wide bushes that have been fitted to 90/110/130/D1 and RRC from around 1992 and the TF529 radius arms are designed to fit Discovery 2.