Grass Roots Toe Adjustment Methods - PeachParts Mercedes-Benz Forum

Air&Road · #1 12-17-2012, 10:36 AM

Grass Roots Toe Adjustment Methods

I have had several requests to describe homebrew toe test and adjustment methods. I have written them numerous times on this forum over the last almost 12 years, but here we go one more time since I have received one very recent specific request.

The vast majority of front tire wear problems are related to toe adjustment. If both front tires are wearing only on the inside or outside edge, then there is about a 99% chance that the problem is incorrect toe adjustment. If both tires are wearing on the inside edge, it is toed OUT. If they are both wearing on the outside edges it is toed IN.

Many alignment specification sheets will indicate a small amount of toe IN. If your goal is maximum tire life, FORGET that specification table and set the toe on ZERO.

Before setting toe make sure that all steering linkage joints are TIGHT. This would include tie rod ends on both end of the outer links and the idler arm bushings. Also ensure that both wheel bearings are properly adjusted with no slack.

Do not measure between particular grooves in the tire tread for setting toe. Tires do not mount perfectly onto rims, so the grooves can be at different points relative to the wheel as you go around the circumference of the tire. Shop based alignment equipment reference the wheel rims for alignment. With my home methods I take this into consideration so as to compensate for any anomalies in tire tread position relative to the wheel.

If after the first series of measurements in either method there is a difference in the measurements, loosen both lock bolts on each tie rod link, this is four bolt and nut combination total. Before turning a link for measurement pay close attention to the directions of the threads. If the steering wheel was centered properly before adjustment procedure, turn each link an equal distance to maintain a centered steering wheel. To adjust toe, either in OR out, turn both links in opposite directions.

If toe is zero, but steering wheel is not centered, turn both links the SAME direction equal amounts in order to maintain toe adjustment, but move the position of the steering wheel.

After finished REMEMBER to retighten all four tie rod link lock bolts and nuts.

Thumb Tack Method:

Press a thumb tack into the deep portion of the tread on each tire on the front of each tire just below a level that allows a tape measure to reach side to side in front and aft of the tire. With both tacks at the same level, measure between the tacks and make note of the measurement.

Roll the car forward far enough for the tacks to be close to the same height, but behind the wheel centerline. Measure again between tacks and if the distance is not the same as previous measurement, adjust tie rods an equal amount on each side and repeat fore and aft measurements moving the car foreward or rearward as necessary for fore and aft measurements. Continue adjustment until the measurements are the same between tacks while tack is either fore or aft. When the measurements are the same, you have achieved ZERO toe.

Tire Scribe Method:

Raise a front wheel safely such that the wheel is suspended and can be turned. Using a pair of vise grips, clamp a good sized nail to the top of a jack stand and position the jack stand such that the nail presses into a flat portion of a raised tread. Turn the wheel 360 degrees to scribe a line all the way around the tire sort of like doing it with a lathe. Repeat on the other front wheel.

Lower the car and roll it at least one full rotation of the tires. This will allow the wheels to seek their correct camber locations after being raised and lowered.

At a level just low enough to miss obstructions in front of and behind the front wheels, measure between the scribed lines. Make note of measurement and make the same measurement between the scribed lines on the back of the tire. If both measurements are not the same, adjust as described above.

Finishing Up:

Don’t forget to retighten the tie rod link lock bolts and nuts after any adjustments were made.