String alignment Question
 

When you measure total front toe Scrugs says straighten 1 wheel and take the difference of the other's front to back. So .25 Toe Out is a difference of -0.125" in front and 0.125" in rear. Why is this not called 0.125 toe out? When ever anyone says I have x" of toe in/out I am equating it to the 1 measurement of the distance in the front of the rim. So to me 0.25" Toe Out means that the front measurement is -0.25" and not -0.125"... Should I be dividing it by 2 when I set my toe to be the same?

Also, why bother straitening a wheel? It seems that you are setting your self up for having a 0" toe on 1 wheel and some other toe on the other wheel when your steering wheel is straight?!?!?! I gues you have to adjust the tirods after that to center it? Is that just to make the 'math' easier? You can't straighten a wheel in the rear so total toe in the rear will require math. Though it seems that Scrugs likes 0" toe in the rear.

... um... hehehe I personally dont like toe in the rear either :D :D :D :D :D

-Michael

I'm sure others will chime in on this as well, but the reference measurements (e.g., 0.25" toe-in) can be interpreted differently based on where you're taking your measurements (sidewall or rim) and -- if rim -- wheel diameter. Much more precise way of describing/discussing angular alignment measures is to reference degrees. Toe-in of 0.25" represents very different angles if measured at tread, sidewall, or rim surface.

BTW, here's a link to help all of us 'home alignment setters & checkers' to convert linear measures to degrees:

Calculate Angle and Sides opposite, hypotenuse, adjacent of right angled triangle calculator

And a couple of other links that I've found useful:

Scruggs -- Home Alignment of Porsche
Do-It-Yourself Alignment


I find it's easier to get a little more precise measurement this way, since -- if you really do get one rim at zero -- the measurement error is limited to the opposite wheel. FWIW, I use the depth reading portion of my vernier calipers for this 'string to rim' measurement; allows me to measure to a more precise and consistent spot on the rim than a ruler might. Plus, reading measurements down to 0.0001" makes me feel better.

Hope this helps

Dale

Absolutely! Totally missed the different rim diameter thing and agree that measuring and reporting as an angle would be a lot better.

I'm also going to use the vernier ;)

-Michael

It is just to make the measurement easier.

When the car is in motion the total toe is split evenly between each front wheel, more or less.

This is why the steering wheel may not be centered when the car is travelling in a straight line.

If you steeing wheel is perfectly centered (in motion) adjust each tie rod exactly the same amount.

I JUST strung my Mini Cooper S a little while back when the person doing the alignment did not check or set the inflation in the tires. I set both tires exactly straight with the steering wheel straight. My thinking is I do not want any Toe out because I was always told that air pressure (Specially on a Rear Steer Car) forced the wheels outward. (On a Front Steer car not so much. The car runs straight with no pulling on a flat road.

Note: the little porsche spec books spec total toe as a degree (0 deg) not a distance. I wonder if people got confused and thought 25' meant .25"... heheheh thats 25 minutes vs. 1/4 inch for the non-engineers...

-Michael

pressed

http://forums.pelicanparts.com/uploa...1291411273.jpg

You just gave me some news. I "Hope" that the fact that I take ALL of the Ball Joints (Tie rod ends. Lower Ball Joints) and install grease fittings that I Grease before I check the wheels.

I "wanted" to do this on the Mini, but on some of the Joints like the Inner Ball Joint, the lower Control Arm is Under the Bottom of the Ball Joint. So I took the Grease fitting Needle and went inbetween the Cups and the Shafts on every joint before I put them back together and pumped in some Good Molly Grease so that the Cups are now not Collasped but well rounded and can continue to supply new grease as movement takes place.