DIY toe angle adjustment

[adurer]

What is your preferred DIY toe angle adjustment method? Please specify what is your alignment base.

[StevesTruck]

Go to a garage for a free tracking check. Tell them I'll come back on payday.

 

Go home, have a guess at adjusting it.

 

Go to another garage that does free tracking checks to see if I got it right.

 

Does help that there's about a dozen tyre places within a mile and a half of here. 

[adurer]

We have no free tracking checks in here. The moment they clamp the lasers on wheels it's 25 Euros.

[juan27]

Theoretically........

 

Measure the track at the front of the tyres (T₁₎ and back (T₂) and distance between front and back (D) measuring points.

Where these points are is not critical as long as they are in the same place on both sides on a horizontal line through the axle.  If you have the same brand tyres on both sides some of the lettering could be used perhaps.

 

Then if the angle of tow out/in = A 

 

Sin(A/2) = ABS(T1-T2)/2D

 

So for example if D = 556mm and T1-T2 = 10mm (ie toe out) then 

 

Sin(A/2) = 10/1112 and therefore A = 2(arcsin(0.00899)) =  1.03^o 

 

(Note I don't know what the actual angle required is)

[StevesTruck]

If I were going to that extent, I'd just use a bit of string (assuming the front and rear track width is equal on these, which I'm sure Haynes has the answer to). 

 

Park your car in front of a fence post or something. Tie a bit of string to the post, and run it around the outside of the car so that it's sat across the face of all four tyre walls, as close to halfway up the wheel as you can without fouling on the bodywork. Tie the end off on the post. Toe out will show as a gap between the string and the rear of the front tyre, tow in shows as the strong wrapping over the same tyre wall. 

[O.C.D.]

Theoretically........

 

Measure the track at the front of the tyres (T₁₎ and back (T₂) and distance between front and back (D) measuring points.

Where these points are is not critical as long as they are in the same place on both sides on a horizontal line through the axle.  If you have the same brand tyres on both sides some of the lettering could be used perhaps.

 

Then if the angle of tow out/in = A 

 

Sin(A/2) = ABS(T1-T2)/2D

 

So for example if D = 556mm and T1-T2 = 10mm (ie toe out) then 

 

Sin(A/2) = 10/1112 and therefore A = 2(arcsin(0.00899)) =  1.03^o 

 

(Note I don't know what the actual angle required is)

EEH....!!!!!!

[TeflonTom]

Whs^^

I guess in theory it must be possible to manufacture a jig to get it 99% there! when I put my 20v car together I did it by eye and when I had it checked it was so close they didn't even need to adjust it.

[adurer]

Here is my concern: toe angle is measured taking the longitudinal axis of the car as reference.

 

You got to have a fixed point or axis on the car as reference, otherwise you're building on sand so to speak. You definitely don't take a fence as reference It's my opinion that any measurement method based only on front wheels tracking is wrong. See why below. A and B are the typical measurements for DIYers.

 

 

That is why garages use back wheels as reference. If the chassis is not damaged, back wheels are almost parallel (well, they have a toe-in on Felicia, but anyway) and we may count on that. But here's when things get ugly: front axle tracking is 1420 mm while rear axle tracking is 1380 mm. Go figure...

[James I]

We set the rally act up with castor and camber gauges, for the toe in and out we use two parallel pieces of string, set to an exact rectangle with the car in the middle.

 We have 10mm from the string to the centre of the wheel, then simply measure between the front and back of the front wheel rim to the string to see if it toes in or out. When I first saw this done I laughed and told the lads they were mad, when we had it verified on a prier alignment set up they had the last laugh as it was spot on!

 

Make sure you set up accurately.

[dohnjoe]

adurer

you can place a 20 mm wood board on each rear wheel and then use a string passing over the board to front wheels.

the string should touch front tyre in 2 points because with the help of the board the tracking of rear and front wheels is equal.

[adurer]

Yeah, that might do the trick.

[uma1998]

I had four wheel done on mine and adjusted it to the computer mates tyre shop found it better then the laser adjustment

[Red Studio]

I think my understanding must be a bit foggy.

 

I don't follow why turning the steering wheel a little to the right wouldn't bring the wheels to centre and result in a zero angle in the diagram in adurer's post (number 8). Isn't the toe in or out just the difference in angle between the two wheels and not an absolute relative to the car? Wouldn't this angle between the two wheels be much the same even if the wheels are turned slightly to one side or other of dead ahead - so long as it is only slightly?

Edited 20 November, 2013 by Red Studio

[TeflonTom]

No, because the wheels turn at different rates due to angular displacement... Look up Ackerman steering angles on google.

[adurer]

I will try to explain STEP BY STEP in more detail what happens when we do an alignment job in our garage and why I felt the need to consult all of you. Feel free to correct my spelling or style if there are any ambiguous terms. Also feel free to correct my method and improve it.

 

Let's say we did a suspension or steering job and our toe alignment is all over the place. Remember for later that we don't have in our garage the luxury of sitting front wheels on easy rotating plates. For an easier understanding let's say we end out with a 2 deg. toe out on front left wheel and a 3 deg. toe out front right wheel having the steering wheel centered. See illustration below (angles and distances are intentionally exaggerated for better view).

 

 

We start by adjusting the left track rod length. But here's the catch: when do we know we have zero toe? What is our reference? The right wheel?? No way, it's crooked. You can't rely on a moving part as a base for future measurements. So what is a fixed reference? Well... if the chassis and rear wheels are not damaged... we can use for now the rear left wheel to align the front left wheel. How do we do that? See next illustration.

 

 

We need a 5 meter piece of string and a 20 mm thick wood board (thanks dohnjoe). Why 20 mm? Because on Felicia rear wheels tracking is 1380 mm and front wheels tracking is 1420 mm. That means a difference of 40 mm hence 20 mm for each side. The string is knotted to the back of the body and routed over the center of the wheels. We watch the string to barely touch the sides of front left tyre. Then we repat this operation for the right side.

 

The final adjustment. Because in reality on Felicia rear wheels have a toe-in angle from factory and because tyres don't rotate so freely on the garage floor when we adjust track rods length, we need a final adjustment. The Internet is full of bad videos showing only this final adjustment and leaving the impression it is correct just to measure the distance between front wheels and you're done. In fact, without a prior preparation shown above, that is using a fixed reference, you may end up with an incorrect toe angle as I explained in short in my previous post.

 

 

As you see, we measure the distance between the front side of the tyres A and the rear side of the tyres B and adjust equally on both track rods till A=B

 

One last note: people say you can sit each front wheels on 2 floor tiles back to front having grease in between for an easy rotation during track rods adjustment.

Edited 20 November, 2013 by adurer

[uma1998]

That won't work for me as running rear disk just go to a garage and have it done on computer alignment

[Red Studio]

Magic! Thanks Tom and Adurer.

I see the Ackerman Steering angles. Never ever occurred to me, the inside wheel turns tighter. Geometry of the steering, angle of steering arms etc. have to take care of that.

I found this diagram helpful:

http://en.wikipedia.org/wiki/File:Ackermann_turning.svg

Just one more question for Adurer - if the steering is centred i.e. with both wheels the same angle, the measurements are aimed at ensuring the steering wheel and rack are centred too?

Put another way - say the wheels are centred, toe angles are correct but the steering wheel points to one side why would unbolting the wheel and putting it back centred be wrong? I may be answering my own question but is it that the relative lengths of the track rods will be unbalanced and so the ackerman steering angles will be thrown out?

Edited 20 November, 2013 by Red Studio

[adurer]

@Red Studio

There are two possible solutions (if I understood your question correctly): the quick solution and the correct solution.

 

The quick solution

If you have true zero toe angle but the steering wheel is not centered, you just take out the steering wheel straight then you reinsert it on different splines so that it is centered. Job done.

 

The correct solution

One thing often overlooked by DIYers is to check for equal steering wheel turns to full left and to full right. In other words, if it takes, let's say, 3.5 turns (1260 degrees) from full left to full right, then you will have to make sure the steering wheel turns 1.75 turns (630 degrees or 1 turn + 270 degrees) both to full left and to full right starting from the centered position corresponding to zero toe. If you need to know how to adjust the steering in case full left and full right turns don't match, just ask.

[TeflonTom]

On the right hand drive Felicia's the steering column has a centre mark so you can align the steering wheel with the column so there's no messing about with moving the steering wheel.. The accepted method when adjusting the toe settings is to turn the steering wheel till it's in the central position, then clamp it so it can't move, then adjust both front wheels on the tie rods till the toe settings are in spec.. However on some vag group cars like early polos and golfs, only one of the track rod ends is adjustable so you turn the steering wheel till that wheel is correct then adjust the other one..

[adurer]

Tom, can you show on a photo where is that center mark please?

[TeflonTom]

It's on the the very tip of the column where the nut that holds the steering wheel goes, it's a dimple that is machined into the shaft.

[adurer]

Well... lucky you I went to my car to check and no dimple :( I don't think it has to do with LHD/RHD but maybe with the year of fabrication. Mine is 1997

[Red Studio]

Thanks to both of you. I know it's pretty simple stuff when there are people on here completely rebuilding their cars from the ground up but as someone who generally leaves the more complicated stuff to the professionals it's good to find out more about stuff like this that I can understand.

 

The next question for me would be DIY measurement of other steering angles. I've previously hit a pot-hole hard enough to throw out the caster angle on my left front wheel which the tyre depot didn't spot when I took it in to be checked because it was pulling to one side. I know it's the angle that the steering is inclined backwards but how can you measure that?

[adurer]

Caster angle is measured using a special camber gauge (see Gunson) and a pair of turntables to measure turning 20 degrees in each direction accurately. It's not a DIY job and it's not about toe, so... it's off-topic. But I've learned there are garages in the UK that do free steering geometry checks. Anyways, caster angle is not adjustable for Felicia, so all you can do is to change the part that bent.

Edited 21 November, 2013 by adurer

[adurer]

I made an error in post #15 (second paragraph) of this topic.

 

Please read correctly "For an easier understanding let's say we end up with a -2 deg. toe (out) on front left wheel and a -3 deg. toe (out)..."

 

Sorry.

Edited 21 November, 2013 by adurer