Alignment Specifications

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Super Duty Alignment Specs

 Caster = min 4°/max 8°, optimal is 5° to 6°, max cross center caster 1° as needed to reduce pulling.

 Toe = Toed in each side min .12°/max .18°, .18° is optimal, max toe in is optimal.

Camber = ± Min 0°/Max .5°, optimal is 0, max cross camber .5° as needed to reduce drift.

Caster & Camber

Negative caster should never be used on any vehicle. If the question is positive or negative caster, the answer is always, 100% of the time, positive caster. Cross caster can result in the vehicle to pulling to the Lower number side. For instance, if drivers’ side has 2.3 degrees and the passenger side has 2.6 degrees this should get the truck to go straight on a crowned road but could pull to the driver side on flat road. After the parts and tires have been ruled out, most alignment techs will take a closer look at cross caster as directional control angle, which is taught in many wheel alignment classes today. However, cross camber also affects directional stability, but it is usually ignored because camber also impacts tire wear. Some vehicles in production today have steering axis inclination (SAI) values of 9°, or even higher, to improve vehicle stability. On these vehicles with higher SAI values, the cross camber can be more effective in resolving drift than cross caster.

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*motor.com

One of the common handling-related complaints brought to an alignment shop is "drift" - usually meaning the vehicle fails to continue straight when allowed to choose its own path. Many times, an alignment tech is able to easily resolve drift issues, but not always. Making adjustments and then failing to impact a drift issue or satisfy the customer's complaint can be frustrating. Tire pressure is the #1 thing to always check. It is very very common for drivability issues to be caused by tires. Some brands of new, with zero mile tires do not drive nice on solid axle truck and no alignment will fix this. Never rule out the tires for being the problem because you can chase .2° alignment changes for months only to swap out the tires and it is a completely different truck.

 

Lets clarify drift by popular definition: with no driver input, the vehicle will change one full lane in about 1/8 to 1/4 of a mile on a straight, level road. By contrast, a "pull" is when the vehicle changes lanes faster, about less than 1/8 of a mile. The deliberate use of cross camber we're discussing here is only viable for drifts because a pull would require camber values that are unacceptable for tire wear, and something more serious is possibly wrong. The high value of SAI has a larger influence on vehicle directional stability compared to the relatively smaller caster values. This is why changes in cross caster don't have much effect on drift on certain vehicles. Instead, try small changes in crosscamber by biasing it in the appropriate direction while staying with in the OE specified camber range.

For instance, a vehicle with a left camber of -0.5°, right camber of -0.5° and a drift to the left. This could be corrected by moving the left to -0.75° and the right to -0.5°, or the left to -0.75° and the right -0.25°. Both settings would stay below the typical cross camber maximum of 0.5° and should create enough drift-right to counter the original complaint of drift-left.