Correct your front end geometry after lifting your SuperDuty with this Caster Correction Kit from Carli Suspension. When lifting the front of a Super Duty 2.5", caster will be reduced by 1 degree. The 2 degree shim specified with Carli's 2.5" lift systems not only restores caster but increases it by 1 degree from the stock spec to ensure proper tracking with larger tires. Carli's 4.5" lift systems drop the radius arm pivot point 4.5" to match the lift; thus, caster is maintained. Carli includes the 1 degree shim to increase caster 1 degree over stock for the abovementioned purpose.