Suspension & Steering

Toe-In Measurement Method

Toe-In Measurement Method

DIY Method for Measuring Toe-In:

Nice to see the shop manual is kind of confirming the point I am trying to make with regards to the suspension settling before doing the alignment. You can use tool number 928.123.456 and pull the front of the car down then release it and JUMP all day long on the front of the car. However, the car will not settle much, and certanly not to the eventual ride high of a car that has been driven on a moutain road or for 50 miles or so. Although, this is why the shops can get the closest, but no cigar. I've been driving my car for a 1 week (50 miles and still not settled)and come this saturday, after the race at sears point, the car will have settled 1 more inch. (And stay there until I jack it up again for something.) My alignment is off (toe out) about 2 degrees toe-in for every 2 inches of increasing ride hight.

A good way to check is to get a laser pointer, press against rim pointing down, and make a mark on the floor. Do this for the front of the rim and the rear of the rim, and for both sides of the car. Measure the marks. Trig out the angle for total toe:

1. Difference between the distance betweent the front marks and the rear marks, say 1 inch (77 inches and 76" for example)
2. Divide the difference by 2 (.5")
3. Divide the rim diameter or the distance between the two marking points on the rim by 2 (16" rim, so 8")
4. Divide the .5 inches by the 8" and compute the inverse tangent function on a calculator. (Make sure calculator is set to "degrees," not "radians.")

string isnt the best way, because of the rear of tire string has to go under the car and the motor , header, etc doesnt let you get a straight distance. best way ,is to tie a piece of thread on each end of a level placed against the rim so it is perfectly parallel. tie a couple of needles to the ends to act as the wieght and pointers. mark on the ground where the needles touch. , now measure the distance beween the front marks and the rear marks and then use INV tangent to find the degrees of toe in or out.
most accurate way is to find a very straight piece of metal, and use the tire outside as the mounting points for this measurement.(probably a straight 2x4 will work. just make sure the needle hangs from the same exact point front and rear. Test against a wall or something straight.

example. you might get 66 inches on the front two dots and 65 inches on the rear dots. (ie its toed out by.5 " total or .25 each wheel) Say you use a 2 foot board . take .25 divided by 12 inches (half the board) and take the INV TAN of that number . this will be the toe in or out for one wheel. it works.

For camber , use a bubble level and press against the rim. see how far you need to pull away from top of rim to make straight up and down. measure this distance. Use same formula of above.

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