Sam's DIY Toe/Tracking Calculator

You will need the following:

  • The front and rear track width of the car. It's usually written in the owners handbook.
  • A length of fine string or fishing line, longer than the length of the vehicle.
  • Two chairs or axle stands.
  • A good quality steel rule.
  • This web page.
  • Tools for adjusting suspension geometry. Usually just a couple of spanners.
  • Step 1)
    Park the car on a flat level surface with the steering wheel straight!

    Step 2)
    Tie the string between the two chairs (or axle stands or similar), and stretch out the string along the nearside of the car.

    Step 3)
    Make the string level with the centres of the front and rear wheels.

    Step 4)
    Have a quick look at the calcuator I have created at the bottom of this page. Once you've measured everything it'll tell you what toe you currently have in degrees. For now, just enter in your rim size in inches. Simply 15, 16, 17, etc. If you don't know what it is, look at your tyre markings. For example 205/45/R16 is a 16 inch wheel.

    Step 5)
    Now you need to set the string up so that it is exactly parallel with the centre line of the car. To do this, first enter the front and rear track widths into the calculator I have created at the bottom of this page. With the two values it gives you for A, set the string up accordingly measuring from the centre of the wheels. Measure to the inside of the string as precisely as possible.

    Step 6)
    Measure the distance from the front of the rim to the string (B) and from the rear of the rim to the string (C). Enter these values in the calculator further down this page. Again measuring to the inside of the string as precisely as possible.


    Step 7)
    Repeat steps 2-6 on the offside of the car. You will now be able to fill in all the values for the offside on the calculator at the bottom of this page.

    Step 8)
    You'll now be given a value for nearside toe, offside toe and overall total toe angle in degrees. If the number is a negative number then you have toe-out, and if you have a positive number you have toe-in.

    Step 9)
    Adjust your toe. If you have filled in the "Desired Toe Angle" box on my calculator then it will tell you by how much you need to adjust each wheel to achive that angle. Enter a negative value for toe-out or a positive value for toe-in.

    Get under the car, loosen the nut on the steering arm and adjust the arm as you think necessary. As this is car specific I won't go into detail.

    If the steering arm is in front of the hub, shortening the rod will increase toe-in. If the steering arm is behind the hub, shortening it will give you toe-out. It all depends on the car.

    Fine adjustment is best done by half a turn at a time, driving the car to settle the adjustments you have made (especially if you have had to jack up the car to work on it), then parking up and remeasuring the toe again to see what changes the adjustment has had. Continue until you have achived the toe value you want!

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    Toe Angle Calculator
    Comments and questions to sammyd@mail.com. Sams_Toe_Angle_Calculator.xls

        FILL IN RED BOXES              
                   
        Front Track Width of Car (mm)        
        Rear Track Width of Car (mm)        
                       
        Wheel Rim Diameter (inches) 15,16,17 etc.   Desired Toe Angle (Degrees)      
                       
        Nearside String Set Up     Offside String Set Up    
        Front Wheel Centre to String A (mm)   Front Wheel Centre to String A (mm)  
        Rear Wheel Centre to String A (mm) 100   Rear Wheel Centre to String A (mm) 100  
                   
        Nearside Wheel Measurements   Offside Wheel Measurements  
        Front of Rim to String B (mm)   Front of Rim to String B (mm)  
        Rear of Rim to String C (mm)   Rear of Rim to String C (mm)  
                   
        Toe Angle Calculated     To Achieve Desired Toe Angle  
        Nearside Toe Angle (degrees)   Adjust Nearside by Degrees    
        Offside Toe Angle (degrees)   Adjust Offside by Degrees  
        Total Toe Angle (degrees)