Alignment (Part 4)

After dialing in the camber settings, the next job was to set the toe-in. 

Measuring Ferrari 308 toe-in
Measuring toe-in

The same Tenhulzen equipment is used for the toe measurement but now the two plates are placed against each wheel with two tape measures between to measure the difference in distance between the fronts and the backs of the plates. Slots in the plates hold the tape measures in the correct place. A handy table gives the mapping from distance toe-in to angular toe-in. The plates are surprisingly quick, accurate and easy to use.

Toe distance to angle conversion chart
Toe distance to angle conversion chart

Ferrari specified toe-in as the total toe-in of both wheels measured at the widest part of the tire sidewall. The total difference between those the fronts and backs of the front wheels should be between 1-3mm which corresponds to 0.11° and 0.32° for 16” wheels.

The Tenhulzen equipment was better suited to measure the toe-in at the wheel rim rather than the tire bulge, so this is what I did. The readings I got were still applicable even though I measured at slightly different places since I converted to degrees.

Using the plates I got a consistent reading of 0.35° which was a little too much negative toe-in. More of a concern was that my steering wheel had not been straight for some time. So I had two reasons to adjust the steering rack tie-rods.

Although the tie-rods can probably be adjusted from underneath with the wheels attached, I decided to remove the wheels for each adjustment. It was just more convenient for me to do it that way.  In order to reduce the toe-in, I guessed I needed one complete revolution of the right tie-rod clockwise. And in order to straighten the steering wheel, I guessed I needed 4 complete revolutions of both tie rods anti-clockwise.

Measuring toe-in on a Ferrari 308
Toe-in measured by the disctance between the plates at each end

I got the steering wheel almost perfectly straight with my first guesstimate – complete luck. But my toe-in was now toe-out to the tune of 0.30°. So, lift the car, wheels off, another half turn of the right tie rod back then, wheels on, drop the car and remeasure… 1/16th of an inch difference or 0.16° of toe-in… PERFECT!

My front-end alignment was complete… Now all I needed was a test-drive…

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Disclaimer: 308restoration.com describes the restoration work I perform on my car and only my car. I am not a professional mechanic. The website content is presented for entertainment purposes only and should not be seen as any kind of advice, information, instruction or guidance for working on any other car. The opinions stated here are my own and no-one else’s.

1 Response

  1. Tom J says:

    This was an awesome series of informational articles. Even if I don’t do this myself at least now I understand the complexity of it. Thanks much, very helpful!

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