Too much toe in
Discussion
A bit last minute (for a track day) I've discovered my car was set with 30 minutes of toe in total (0.15 degrees each side) instead of 5 minutes total +/-5
Porsche 993 btw.
Typically, how much do I need to wind the track rod in to get somewhere closer to ideal? I was thinking 1/6th of a turn each side.
Should I even bother?
Cheers!
Porsche 993 btw.
Typically, how much do I need to wind the track rod in to get somewhere closer to ideal? I was thinking 1/6th of a turn each side.
Should I even bother?
Cheers!
Assuming the track rod end is around a 1.25mm pitch then a 16th of a turn will move change the track rod length by 80 microns, which is roughly the width of a human hair.
Pay someone to do it for you.
ETA I've just seen that you actually wrote 1/6, which would only be around 200 microns, so again would make almost no difference what so ever.
ETA there are 60 minutes in 1 degree so 30 minutes would be 0.25deg per side not 0.15deg.
Pay someone to do it for you.
ETA I've just seen that you actually wrote 1/6, which would only be around 200 microns, so again would make almost no difference what so ever.
ETA there are 60 minutes in 1 degree so 30 minutes would be 0.25deg per side not 0.15deg.
Edited by Nick1point9 on Wednesday 1st May 05:50
I did these calculations for my own 993 a couple of weeks ago. If anyone can spot any mistakes please let me know!
170 170 170 170 170 170
0.25 0.25 0.25 0.25 0.25 0.25
1 2 3 4 5 6
0.25 0.5 0.75 1 1.25 1.5
0.001470588 0.002941176 0.004411765 0.005882353 0.007352941 0.008823529
0.001470589 0.002941181 0.004411779 0.005882387 0.007353007 0.008823644
0.08 0.17 0.25 0.34 0.42 0.51
5.1 10.1 15.2 20.2 25.3 30.3
Each row represents:
Length of steering arm (mm)
Change in Opposite side length / flat (since the thread pitch is 0.66 per mm)
Number of flats turned
Total length of Opposite side (mm)
Sine x (where x is the angle between straight ahead and the angle of the wheel)
x (radians)
x (degrees)
x (minutes)
According to the above. each 1/6 ("flat") gives 5.1 minutes of toe in or out depending on which way you're turning the assembly. The calculation is of course specific to the length of the steering arm on the hub but once you've measured this the same calculation can be used for any vehicle.
Nick
170 170 170 170 170 170
0.25 0.25 0.25 0.25 0.25 0.25
1 2 3 4 5 6
0.25 0.5 0.75 1 1.25 1.5
0.001470588 0.002941176 0.004411765 0.005882353 0.007352941 0.008823529
0.001470589 0.002941181 0.004411779 0.005882387 0.007353007 0.008823644
0.08 0.17 0.25 0.34 0.42 0.51
5.1 10.1 15.2 20.2 25.3 30.3
Each row represents:
Length of steering arm (mm)
Change in Opposite side length / flat (since the thread pitch is 0.66 per mm)
Number of flats turned
Total length of Opposite side (mm)
Sine x (where x is the angle between straight ahead and the angle of the wheel)
x (radians)
x (degrees)
x (minutes)
According to the above. each 1/6 ("flat") gives 5.1 minutes of toe in or out depending on which way you're turning the assembly. The calculation is of course specific to the length of the steering arm on the hub but once you've measured this the same calculation can be used for any vehicle.
Nick
Edited by 944Nick on Friday 3rd May 18:47
When you consider I will normally lock the track rod off check the readings on our wheel aligner loosen it off because the toe setting moves when tightened. This process normally takes 3 or 4 goes before I'm happy. Any doing this by measuring threads and adjusting by hope will be just play lucky to get it correct.
944Nick said:
I did these calculations for my own 993 a couple of weeks ago. If anyone can spot any mistakes please let me know!
170 170 170 170 170 170
0.25 0.25 0.25 0.25 0.25 0.25
1 2 3 4 5 6
0.25 0.5 0.75 1 1.25 1.5
0.001470588 0.002941176 0.004411765 0.005882353 0.007352941 0.008823529
0.001470589 0.002941181 0.004411779 0.005882387 0.007353007 0.008823644
0.08 0.17 0.25 0.34 0.42 0.51
5.1 10.1 15.2 20.2 25.3 30.3
Each row represents:
Length of steering arm (mm)
Change in Opposite side length / flat (since the thread pitch is 0.66 per mm)
Number of flats turned
Total length of Opposite side (mm)
Sine x (where x is the angle between straight ahead and the angle of the wheel)
x (radians)
x (degrees)
x (minutes)
According to the above. each 1/6 ("flat") gives 5.1 minutes of toe in or out depending on which way you're turning the assembly. The calculation is of course specific to the length of the steering arm on the hub but once you've measured this the same calculation can be used for any vehicle.
Nick
That assumes that the outboard steering arm is parallel with the vehicle centre line, which it most likely wouldn't be.170 170 170 170 170 170
0.25 0.25 0.25 0.25 0.25 0.25
1 2 3 4 5 6
0.25 0.5 0.75 1 1.25 1.5
0.001470588 0.002941176 0.004411765 0.005882353 0.007352941 0.008823529
0.001470589 0.002941181 0.004411779 0.005882387 0.007353007 0.008823644
0.08 0.17 0.25 0.34 0.42 0.51
5.1 10.1 15.2 20.2 25.3 30.3
Each row represents:
Length of steering arm (mm)
Change in Opposite side length / flat (since the thread pitch is 0.66 per mm)
Number of flats turned
Total length of Opposite side (mm)
Sine x (where x is the angle between straight ahead and the angle of the wheel)
x (radians)
x (degrees)
x (minutes)
According to the above. each 1/6 ("flat") gives 5.1 minutes of toe in or out depending on which way you're turning the assembly. The calculation is of course specific to the length of the steering arm on the hub but once you've measured this the same calculation can be used for any vehicle.
Nick
Edited by 944Nick on Friday 3rd May 18:47
I think we are violently agreeing http://www.pistonheads.com/gassing/imgs/9.gif
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