toe-in and out
Posted: Mon Sep 26, 2005 6:34 pm
Just FYI......
I don't know all the answers on toe-in but I'll give you an opinion. Toe-in is actually a built-in "misalignment" that adds to directional stability (though not as directly as caster), keeps vehicles from wandering since the tires are continually striving to roll on their own axis toward the car's centerline, and creates controlled forces at all movable points to limit shimmy type reactions due to uncontrolled forces oscillating between mechanical tolerance limits . The more directionally true a tire is (as in not wanting to veer left-or-right in a free-rolling state) the less artificial toe-in correction required. Because radials have high-angle belt reinforcement directly beneath the tread, they inherently roll truer than bias tires and generally require less overall toe-in settings in static mode with a near-zero setting possible. In a dynamic mode, toe-in has an opportunity to change due to the interaction of steering linkage and suspension pieces traveling through their respective ranges of motion since everything is anchored at different chassis points. Therefore, some vehicle toe settings are set at a higher than expected value to retain "some" toe-in under all dynamic conditions. When switching from bias to radials it is likely that manufacturer settings can be reduced, but if directional stability/dartiness results, dial more back in. Additionally, unlike bias tires, radials introduce an inherent opportunity for an individual tire to input a persistent "drift" due to minor belt centering issues. If a radial's belts are slightly off-center, one edge ends closer to the tread surface than the opposite edge and the belt has become a cone rather than a hoop. The resulting condition, called "conicity", is not correctable through adjustment settings and can frustrate trouble-shooting of routine alignment tuning, and alignment refinement attempts - especially if converting from bias tires that seldom exhibit ply-steer (non-belted version of conicity) drift to any degree.
Best,
Ray
"Spes mea in Deo est"
[Non-text portions of this message have been removed]
I don't know all the answers on toe-in but I'll give you an opinion. Toe-in is actually a built-in "misalignment" that adds to directional stability (though not as directly as caster), keeps vehicles from wandering since the tires are continually striving to roll on their own axis toward the car's centerline, and creates controlled forces at all movable points to limit shimmy type reactions due to uncontrolled forces oscillating between mechanical tolerance limits . The more directionally true a tire is (as in not wanting to veer left-or-right in a free-rolling state) the less artificial toe-in correction required. Because radials have high-angle belt reinforcement directly beneath the tread, they inherently roll truer than bias tires and generally require less overall toe-in settings in static mode with a near-zero setting possible. In a dynamic mode, toe-in has an opportunity to change due to the interaction of steering linkage and suspension pieces traveling through their respective ranges of motion since everything is anchored at different chassis points. Therefore, some vehicle toe settings are set at a higher than expected value to retain "some" toe-in under all dynamic conditions. When switching from bias to radials it is likely that manufacturer settings can be reduced, but if directional stability/dartiness results, dial more back in. Additionally, unlike bias tires, radials introduce an inherent opportunity for an individual tire to input a persistent "drift" due to minor belt centering issues. If a radial's belts are slightly off-center, one edge ends closer to the tread surface than the opposite edge and the belt has become a cone rather than a hoop. The resulting condition, called "conicity", is not correctable through adjustment settings and can frustrate trouble-shooting of routine alignment tuning, and alignment refinement attempts - especially if converting from bias tires that seldom exhibit ply-steer (non-belted version of conicity) drift to any degree.
Best,
Ray
"Spes mea in Deo est"
[Non-text portions of this message have been removed]