Adjusting front toe-in........
Discussion
I understand that the front toe-in should be 20 minutes. However my tyre shop's 4-wheel tracking gauge can't do degrees and minutes, they want to know what the setting should be in millimetres... anyone out there know the answer?
Whatever the measurement (minutes or millimetres) is that between both wheels or between each wheel and the car's centreline?
By-the-way my car has 15" wheels.
Thanks in advance.
Whatever the measurement (minutes or millimetres) is that between both wheels or between each wheel and the car's centreline?
By-the-way my car has 15" wheels.
Thanks in advance.
Alex,
My understanding is that "toe " or tracking angle is the amount the front of the wheels deviate from the position if they were parallel ( i.e zero toe in) So assuming the wheels effectively pivot around their centre it is the amount they point in ( toe in) or out (toe out) from the zero position. I hope this makes sense.
The 2.2mm is the total toe in for the front i.e. 1.1mm each side.
My understanding is that "toe " or tracking angle is the amount the front of the wheels deviate from the position if they were parallel ( i.e zero toe in) So assuming the wheels effectively pivot around their centre it is the amount they point in ( toe in) or out (toe out) from the zero position. I hope this makes sense.
The 2.2mm is the total toe in for the front i.e. 1.1mm each side.
John,
To check tracking:
Lock the steering in the straight ahead position before starting
Ensure the wheels are in the position that is the normal driving position, if the car has been jacked up push it too and fro a few times to settle the suspension.
Some string is positioned about 2" away from the hubs at hub centre height and supported tightly on 4 axle stands, 2 in front and 2 behind the car. The string has to be parallel to the cars centre line, not the hubs, as the front and rear wheels may not be same distance apart. The string is then carefully adjusted to be equidistant from the front hubs and then the back hubs(As mentioned above these two measurements could be different if the axle widths are not the same). This string then represents the datum to take accurate measurements.
Choose parts of the rim that have not been curbed and carefully measure the distance from the string to the edge of the wheel rim at the front and compare this to the measurement to the edge of the rear rim, both at hub centre height this then represents 2x the toe in.
Because: If h = distance from the string to the hub centre, then for "toe in,x " the distance from the string to the front rim = h+x and that for the rear rim = h-x.
If we subtract these two measurements (h+x) - (h-x)= 2x
Therefore the toe in(x) on each wheel = half the difference in the two above measurements.
Hopefully this makes sense. It is much easier to carry out in practice than to explain.
Beware some of the methods shown on U-Tube:
Measuring with the wheels off the ground is almost bound to introduce errors due to bump steer etc.
Measuring the tyres themselves assumes the tread is perfectly even which it probably isnt.
Dont assume that the front and rear tracking are the same (i.e. width of each axle to the outside of the hubs)The Griffith 500 is 1460mm front and 1470mm rear but earlier models may differ.
To check tracking:
Lock the steering in the straight ahead position before starting
Ensure the wheels are in the position that is the normal driving position, if the car has been jacked up push it too and fro a few times to settle the suspension.
Some string is positioned about 2" away from the hubs at hub centre height and supported tightly on 4 axle stands, 2 in front and 2 behind the car. The string has to be parallel to the cars centre line, not the hubs, as the front and rear wheels may not be same distance apart. The string is then carefully adjusted to be equidistant from the front hubs and then the back hubs(As mentioned above these two measurements could be different if the axle widths are not the same). This string then represents the datum to take accurate measurements.
Choose parts of the rim that have not been curbed and carefully measure the distance from the string to the edge of the wheel rim at the front and compare this to the measurement to the edge of the rear rim, both at hub centre height this then represents 2x the toe in.
Because: If h = distance from the string to the hub centre, then for "toe in,x " the distance from the string to the front rim = h+x and that for the rear rim = h-x.
If we subtract these two measurements (h+x) - (h-x)= 2x
Therefore the toe in(x) on each wheel = half the difference in the two above measurements.
Hopefully this makes sense. It is much easier to carry out in practice than to explain.
Beware some of the methods shown on U-Tube:
Measuring with the wheels off the ground is almost bound to introduce errors due to bump steer etc.
Measuring the tyres themselves assumes the tread is perfectly even which it probably isnt.
Dont assume that the front and rear tracking are the same (i.e. width of each axle to the outside of the hubs)The Griffith 500 is 1460mm front and 1470mm rear but earlier models may differ.
Thanks for replies. Seems I'm not the only one who was confused, this link is quite helpful.
http://www.lotuselan.net/forums/lotus-suspension-f...
http://www.lotuselan.net/forums/lotus-suspension-f...
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