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You are correct, I am aware of this. I am not running toe out in the front. I am actually running a decent amount of toe in to keep the car from wandering and being darty, since it is a street car.
I have seen toe measured two different ways and I do not know how it translates into minutes, but my front toe settings are listed as .05" each side, for a total of .1" of toe in. That is how it reads on my alignment sheet.
To convert between toe distance (mm or inches) and angle (degrees or minutes), toe_angle = arcsin(toe_distance / wheel_diameter)
For example, 2mm toe on a 20” (508 mm) wheel is 0.226 degrees (13.5 minutes).
In your example, 0.05” of front toe in on a 20” wheel is 0.143 degrees (8.6 minutes).
NOTE: I’m not sure if it’s defined with arcsin or arctan, as I’m not sure of the geometric meaning of the distance based toe measurement. Anyway, even if it should be arctan instead of arcsin, it doesn’t make much of a difference for small angles (as cos(x) ~= 1 for small x).
@wizee I use d*sin(ϴ) = x where x is the 'mm' measurement, d is the diameter, tho i thought it's the tire diameter. For small ϴ, sin(ϴ) ~= ϴ, so this goes to d*ϴ = x but don't forget to convert degrees (or mins) to radians for that to work. Really wish the industry would move to just stating the angle in degrees for this.
@wizee I use d*sin(ϴ) = x where x is the 'mm' measurement, d is the diameter, tho i thought it's the tire diameter. For small ϴ, sin(ϴ) ~= ϴ, so this goes to d*ϴ = x but don't forget to convert degrees (or mins) to radians for that to work. Really wish the industry would move to just stating the angle in degrees for this.
Some go by wheel diameter, some go by tire diameter, some go by brake rotor diameter, some go by some hypothetical typical wheel or tire diameter. Then the measurement depends on your tire size and brand and model of choice and air pressure (since not all tires of the same size are the same size), or the brakes you chose, or the wheels you chose, or the "typical" wheel or tire diameter the person likes. Measuring angles as a length is rubbish and we ought to banish this practice.
Some go by wheel diameter, some go by tire diameter, some go by brake rotor diameter, some go by some hypothetical typical wheel or tire diameter. Then the measurement depends on your tire size and brand and model of choice and air pressure (since not all tires of the same size are the same size), or the brakes you chose, or the wheels you chose, or the "typical" wheel or tire diameter the person likes. Measuring angles as a length is rubbish and we ought to banish this practice.
so, I am still kinda lost here.
What are my toe in measurements in mm for front and rear?
What are my toe in measurements in mm for front and rear?
0.05” (your front per side toe in) is 1.27 mm, and 0.10” (your rear per side toe in) is 2.54 mm.
The confusing part is that what we care about (and is unambiguous) is the angle. The conversion from toe distance (mm or inches) to toe angle depends on how the toe distance was measured/calculated. Some measure based on wheel diameter, some measure based on tire diameter, some based on something else. The angles hand written beside the toe distance on your sheet suggest the toe distance may have been calculated/measured using tire diameter rather than wheel diameter.
Yeah, that is my thinking as well, either the solid puck is filtering out that isolation that was present stock, and/or the amount of negative camber is keeping enough of the contact patch off the ground during straight line driving.
I have reduced that feeling quite a bit by upping the compression/rebound settings on the MCS dampers, but the wheel still feels more "alive" from stock form. It is only annoying on extreme roads now and not on all roads. So, at this point it is not enough to spend additional money figuring out or altering my alignment settings.
I thought about doing a bump steer sweep, but the costs of that are too much for an unknown result.
I went with the Elephant Thrust Arm Bushings, which are infinitely adjustable.
Read https://en.wikipedia.org/wiki/Camber_thrust
This will explain why more negative camber can make your car more darty/alive on sketchy roads. Tire construction also plays a part in this so different brands can feel different. Braking generally increases front negative camber so you will notice more car/steering wheel movement when braking compared to that when just driving, etc., etc.
Read https://en.wikipedia.org/wiki/Camber_thrust
This will explain why more negative camber can make your car more darty/alive on sketchy roads. Tire construction also plays a part in this so different brands can feel different. Braking generally increases front negative camber so you will notice more car/steering wheel movement when braking compared to that when just driving, etc., etc.
It's not the car though that is darty. The car itself tracks straight as an arrow.
It is all in the steering wheel and the little jerks as you transverse uneven pavement and broken pavement. You can let the steering wheel go and watch it jerk to the left or right , then immediately it will re-center itself, before the car actually responds to it, but it is that constant jerking feeling of the wheel that gets annoying.
I drove the car home 500 miles from the dealership and it did not do it then, and it was only after I started messing with the alignment that it came about.
04-15-2022, 09:48 PM
