Adjusting Toe-in Using Tape Measures

Fellow 912 owner Sterling Vaden was the inspiration for this article. He showed the use of an angle iron to do toein measurement.

This discussion emphasizes the rear wheels because for the last go around, they needed correction and the front wheels did not. But the identical measurement is used for the front wheels. Adjustment will be made by loosening and twisting the tie rods. getting the wheels straight ahead involves checking the steering wheel angles when cranked all the way in each direction. Centering the steering wheel is done by rotating both tie rods the same amount. Finally, crosscheck the final result by making the toein measurement again.


My '66 owners manual says front 40', rear 0.

The owners manual in the Orange book says front 40', rear 0 +/- 10'

The factory manual says front 15' to 20', rear 0'.

Later manuals say front 0. There is general agreement that rear toe out is not good for stability.


IMG_6204 Sports car racers often use Aluminum Plates (do a search for 'Longacre toe plate') to measure toe-in at the track. The plates are available commercially for less than $60. The plates are placed against the wheels on each side of the car. Each plate has a pair of slots cut in the side for tape measures to be stretched between them. If there is zero degrees of toein the distance measured at the front of the tire will be the same as the distance at the rear of the tire.

We can emulate that technique at home by cutting some 2 inch aluminum angle into a pair of 26 inch lengths. We found a 96 inch length of the material at Home Depot for $15. Plenty of material was left over in case we made a mistake on cutting or if by mistake we drive over one of the pieces.
IMG_6207 You will need a pair of measuring tapes. Slots have to be cut into the ends to capture the end of the tape at one and and to provide a controlled mark at the other end of the tapes to provide the measurement.

We made the slots 1/8 in. wide and an inch long and tested to see the slot was wide enough for the tape.
IMG_6217 Next mount each aluminum angle on a board. We used a 2 x 6 x 10. The mounting does not have to be secure - a single screw will do fine.
IMG_6208 Now you can do a trial setup, placing each aluminum angle against a tire and stretch the tapes between them. Check under the car for clearance. We had to reduce the height by ripping a piece off the boards to get free clearance under the car for the tapes.
IMG_6209 Here we are set up for a toein measurement on the rear wheels. The tale of the tapes shows we have too much toein by a half and inch. The goal is zero degrees or a bit negative. We certainly do not want toe out or the handling will suffer. Lets make and adjustment to one side to reduce the toein.
IMG_6211 We want to make and adjustment to one side to reduce the toein. But which side? If we pick the wrong side the car could go down the road like a crab.

The last time I adjusted the toein, I cranked in toein to some arbitrary amount on both sides overcoming a natural tendency on my car towards toe out. We will fix the toe out by relaxing some of this. One way is to measure the distance from the wheel and the body.

Here I pick an easily made measurement on both sides and will make the adjustment on the side with the shortest measurement. This is the right side which is about 1 cm shorter.
IMG_6212 Changing the toein requires loosening the four bolts holding the end of the spring plate. In our case we are lengthening the distance from the front of the car to the wheel. First mark the current position. I just used a pencil mark on the inside of the banana arm cut out.
IMG_6213 Increase the toe out by twisting the adjustment screw on the right. This is done with a 12 mm Allan wrench. That is part of your tool kit, right?

Thanks to our mark we can see how much movement has been made. My target was to eliminate the 1 cm. difference between the two sides.

The inner adjustment will change the camber. When I find and electronic protract or with 0.1 degree precision, we can check and adjust camber. Normal pro tractors do not have adequate precision.

After the change, all four screws are retightened.
IMG_6214 Tighten everything, put on the wheel. Don't forget to torque the lug nuts to 94 foot-lbs.

The absolute value of the the measurement is not important. We are looking for the difference between the two tapes. Maintaining toein requires the front tape be a shorter distance than the rear tape.
IMG_6215 Our toein measurements are 3/8 in different or there is 3/16 inch of toein over a distance of 25 inches for each wheel.

From trigonometry:

If the two sides of a triangle are 'a' and 'b' and the hypotenuse is 'h'

tan A = a/h

tan A = (3/16) / 25

tan A = 0.1875 / 25

tan A = 0.0075

A = 0 degrees 26 min

So. We still have a bit too much toein, need to get it down to 1/8 in. total
IMG_6218 Well, I drove the car to work today and see there is a bit more work to do. The rear wheels are parallel, but are pointing slightly to the right - the car is crabbing. I could tell because stable steering had the steering wheel off center to the right.

But we can use one of those cheap laser levels to sight toward the front of the car. Place the level as shown, check the spot and then turn the level upside down and check the new spot. The rear tires actually point toward a point half way between the too spots. This is because the light does not come straight out the level when it is oriented as shown. At the front wheels the two spots are about an inch and a half apart. Yours will be different, but do not assume the light exits parallel with the level.

Now we can move the level to the other side of the car and check again. This confirms that adjusting just the passenger side was a bit optimistic. So, jack up the rear, remove the wheels, cut the passenger adjustment back and add some adjustment to the drivers side. Tighten everything again, drive around the block to get the suspension level and check both the toein and where the wheels are pointing. Close enough. Test drive on the highway and find stable steering has the wheel much closer to centered. We are good to go for one more trial.

And then...

After one more tweek, The wheels are pointing straight ahead according to the laser and the total toein is 1/8 in or about 8 minutes per side.
Last modified: Mon, 20 Jun 2005


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