Wheel Alignment.

[Bodgedbuild]

I agree with the other stuff (although not many cars have the rack ahead of the axle these days), but I find the drive-over ones aren't very repeatable - especially when you get sportier setups with wide tyres and a fair bit of negative camber.

I agree they are not that repeatable, to an extent, but they do give a very quick indication of whether it is toeing in or out but more importantly they account for a certain amount of wear too and as such are "dynamic". Generally a front wheel drive needs to be toeing out when static and rear wheel drive toeing in but the goal is the same for each, to be pretty much parallel while driving. That's what I like about they drive over ones or even old glossy magazines/tea trays or similar ( to see which way the pages/trays get twisted).

 

[Avocet]

You have dug your own hole. Now, how do you climb out of it? The geometry changes from wear and tear. It changes from variations in replacement parts. It changes when people play thread counts on the tie rods. It changes from your gradually getting fat from talking on the internet too much.

Here we go again...

The primary cause of suspension geometry changing, is people not knowing their arses from their elbows - as you so ably demonstrate!

Let's take each of those in turn, shall we?

1. "Wear and tear". What sort of percentage change in length do you get in the radius of the arc described by the track rod if either the inner balljoint or the trackod end is worn? The answer is "naff-all"! Let's say your track rod, between ball centres, is a foot long. How much movement does there have to be in a balljoint before you regard it as "worn"? 1/16"? 1/32"? So that makes the radius described by the track rod, change by a miniscule amount! What's more, given that it is play, it generally changes by a random amount, depending on which way it is loaded. You get a knocking noise, you get uneven tyre wear, but you don't get any appreciable change in the amount of bump-steer!

2. "Variations in replacement parts". Really? Yes, of course there are variations, but in these days of computer-aided manufacturing, they are very small indeed. You would also have to end up in a situation where the variations didn't cancel each other out, depending on how many parts you replaced.

3. "playing thread counts". You do realise that manufacturers make them adjustable deliberately, don't you? In fact, when you look at the amount of adjustment on a typical track rod, it should give you an indication of just how much the length of the rod can change, before the bumpsteer characteristics change!

4. "gradually getting fat from talking on the internet too much". Hmmmm.... interesting.... You do, of course, re-do your tracking each time your weight changes, I assume? My car might go down on its suspension by half an inch or so, when I get in. Even more, if the whole family gets in with me! I notice the manufacturer has a sticker on the car, with different tyre pressure recommendations depending on whether it's running light or fully-laden, but as yet, I haven't noticed any different tracking recommendations for different load conditions... It's almsot like he has a single load condition specified for doing the tracking, and then he thinks the car is fine for all permitted load conditions thereafter!

 

[Avocet]

I agree they are not that repeatable, to an extent, but they do give a very quick indication of whether it is toeing in or out but more importantly they account for a certain amount of wear too and as such are "dynamic". Generally a front wheel drive needs to be toeing out when static and rear wheel drive toeing in but the goal is the same for each, to be pretty much parallel while driving. That's what I like about they drive over ones or even old glossy magazines/tea trays or similar ( to see which way the pages/trays get twisted).

The good thing about them (apart from the speed and convenience), is undoubtedly that you're getting a true reading of what the wheel is doing as you drive the car. It's a long while since I've seen anyone using them, though. I sometimes wonder whether there's a certain amount of "bullshit baffles brains" at work, when a garage invests in a shiny new laser alignment kit, though? To the punter, I'm sure it looks a load more impressive than a couple of mats with pointers on them!

I have done tracking (at both ends) just with a "string box" around the car, in the past. However, it takes bloody ages to set up accurately, and you have to be so careful taking the measurements.

 

[EFLImpudence]

I use one of these, and have been very pleased with it:

Trackace Laser Wheel Alignment Gauge

The Trackace Laser Wheel Alignment Gauge is the World's first auto-calibrating, laser accurate tracking gauge, designed for home use and simple storage. Suitable for use with wheels ranging in size from 10” to 22” and accurate to 1' (0.0166 decimal degree), it gives fast, very accurate readings...

www.demon-tweeks.com

Yes, I have been looking at that product.

Mine came free with my house...

In fact, I was lucky enough to find some in my garage too, when I looked!

There was a wheel alignment print-out from last November with the documents when I bought the car.
It shows the required toe-in values and tolerances and the settings made. Left wheel is not even within tolerance and the right only just.
So much for precision of the centres - as I have found before.

Correcting these adjustments would cause the steering wheel to move even farther to the left.


Obviously there is no knowing what has been altered since then.

 

[Mottie]

I use these ones. Super tracker ST100. Basic, but they do for me.

 

[Avocet]

Yes, I have been looking at that product.





There was a wheel alignment print-out from last November with the documents when I bought the car.
It shows the required toe-in values and tolerances and the settings made. Left wheel is not even within tolerance and the right only just.
So much for precision of the centres - as I have found before.

Correcting these adjustments would cause the steering wheel to move even farther to the left.


Obviously there is no knowing what has been altered since then.

Can you post-up a scan or screen shot of the readout on here, and we can have a look?

I wouldn't get too hung-up about the same number of threads going into each track rod end, provided there was enough thread engagement on the one with the least thread in it. As a rule of thumb, you'd be wanting at least 1.5 D (where D is the diameter of the thread, so if it's a 12mm diameter thread, at least 18mm of track rod screwed into the track rod end). Some racing folk seem to go down as low as 1.25D but I wouldn't on a road car.

As others have said, centralising the steering wheel is important, for a variety of reasons:

1. The airbag will probably be triggered by a "clock spring" bit of ribbon cable that just winds and unwinds as the wheel is turned left and right. There will be SOME excess slack in it, but if the rack is way too far off centre, you might snap (or unplug) the ribbon cable at full lock, one way or the other.

2. The same applies to steering wheel controls for the radio, etc. In fact, it's often the same cable.

3. If the car has Electronic Stability Control, there will be a steering angle sensor on the steering column somewhere. If the wheel (and thus column) isn't too well centralised, the system will think that you're having to steer slightly left or right, in order to go in a straight line. It will also have a yaw rate sensor (not on the wheel or column, elsewhere in the car), that will be telling the system the car isn't turning even though the steering wheel is. Depending on how sophisticated the system is, it will either put up a warning light, or the ESC system will activate and skid the car round a bit, in order to "save you", because it will assume the car is skidding and you're trying to correct it to go in a straight line!

4. Again, as has been said, you might have a variable ration rack, which will then give uneven performance lock-to-lock, because the ratio will start to vary sooner on one side than the other.

For those reasons, I'd be inclined to centralise the steering wheel and then adjust both track rods to get the wheels pointing the right way, and see what the track rod ends look like when you do. Remember that the gauge above can only tell you TOTAL toe, so if one side is toeing out by (say) half a degree, and the other side is toeing in by half a degree, the gauge will show zero toe. In reality, to go in a straight line, you would then turn the wheel slightly to one side, so that they were parallel and the steering wheel would then be off-centre.
Lastly, if the steering wheel is off-centre to go in a straight line and the car has had a bit of a knock, don't rule out the possibility that the REAR tracking is out! Your front tracking might be fine, but if the rear is out, such that the back end is trying to turn (say) slightly to the right all the time, you'll end up turning the steering wheel to compensate and the car will drive straight, but it will be "crabbing" slightly. Proper 4-wheel alignment is your only practicable option, if that's the case.

 

[carmanmemoranda]

The good thing about them (apart from the speed and convenience), is undoubtedly that you're getting a true reading of what the wheel is doing as you drive the car. It's a long while since I've seen anyone using them, though. I sometimes wonder whether there's a certain amount of "bullshit baffles brains" at work, when a garage invests in a shiny new laser alignment kit, though? To the punter, I'm sure it looks a load more impressive than a couple of mats with pointers on them!

I have done tracking (at both ends) just with a "string box" around the car, in the past. However, it takes bloody ages to set up accurately, and you have to be so careful taking the measurements.

There is some of that in here too.

Tracking is a very simple thing, made complicated by a few. It can be checked by string, tape measure, bent metal strips etc. But it all takes time and patience and repeated measuring and adjustments. Proper gauges help it to be quicker and more reliable measuring. But good equipment in bad hands is a common occurrence. In fairness to most equipment suppliers now, most of what they produce is made to be fool proof in use. It shows why.

 

[Avocet]

There is some of that in here too.

Tracking is a very simple thing, made complicated by a few. It can be checked by string, tape measure, bent metal strips etc. But it all takes time and patience and repeated measuring and adjustments. Proper gauges help it to be quicker and more reliable measuring. But good equipment in bad hands is a common occurrence. In fairness to most equipment suppliers now, most of what they produce is made to be fool proof in use. It shows why.

I can absolutely agree with that. A lot of the cost of the high-tech equipment simply allows a much faster turnaround time between jobs. If I'm doing it with string, it will take me the best part of an hour to set everything up so that I have the string box exactly parallel to the vehicle centreline and equidistant from the centre of each wheel on each axle. Once I've taken the measurement, and made the adjustment, I need to roll the car and then set it all up again to check. It can take a whole morning, very easily.

As for the modern stuff being idiot-proof, the two biggest things I see with mechanics, are rough handling and not enough care in getting the gauges accurately against the wheel.

 

[Mottie]

As for the modern stuff being idiot-proof, the two biggest things I see with mechanics, are rough handling and not enough care in getting the gauges accurately against the wheel.

Most common mistakes I see are not carrying out any pre-checks on steering joints and wheel bearings, not doing it on level ground and not checking the tyre pressures.

 

[Avocet]

Most common mistakes I see are not carrying out any pre-checks on steering joints and wheel bearings, not doing it on level ground and not checking the tyre pressures.

Level ground isn't that big a deal for toe, but makes a lot of difference for camber.

 

[EFLImpudence]

Can you post-up a scan or screen shot of the readout on here, and we can have a look?

Yes, here it is with the worst bits underlined.
I suppose anyone satisfied with that may well have not bothered with the steering wheel position.

I will do as you suggest and see how it turns out.

 

[Bodgedbuild]

The good thing about them (apart from the speed and convenience), is undoubtedly that you're getting a true reading of what the wheel is doing as you drive the car. It's a long while since I've seen anyone using them, though.

Another positive for the drive over alignment tool is it takes away any error caused by a defect or buckle on the wheel rim as it literally just "detects" the "pull/twist" of the tyre against the road. I have a Trackace and it is ok but I find the laser too dim (maybe green would be better?) and the only place I can find locally that is smooth enough and flat enough to use it is a petrol station. This is because both the mirror and laser parts a placed on the ground rather than hung off the wheel. I also don't necessarily track to exactly what is specified, in the past if myself or a friend finds the steering a little numb, I might toe it out just a whisker and if it's too sensitive, toeing it in a whisker tends to numb it down a bit. The same can apply if a tyre is feathering on inside or outside edges....

 

[EFLImpudence]

Just to say the car(van) is very old so not many sophisticated electronics on steering wheel - 1996 (1995 model) Toyota Previa but is in excellent condition with only 50,000 miles - verified as well as can be.

 

[Avocet]

Another positive for the drive over alignment tool is it takes away any error caused by a defect or buckle on the wheel rim as it literally just "detects" the "pull/twist" of the tyre against the road. I have a Trackace and it is ok but I find the laser too dim (maybe green would be better?) and the only place I can find locally that is smooth enough and flat enough to use it is a petrol station. This is because both the mirror and laser parts a placed on the ground rather than hung off the wheel. I also don't necessarily track to exactly what is specified, in the past if myself or a friend finds the steering a little numb, I might toe it out just a whisker and if it's too sensitive, toeing it in a whisker tends to numb it down a bit. The same can apply if a tyre is feathering on inside or outside edges....

I can see mine OK? The ground doesn't make much difference, because as long as the two plastic fingers are both touching the rim, you'll get a true reading. If the ground was very uneven, then perhaps the angle that the mirror sat at, would mean it was hard to get the laser to bounce off it and still be visible on the scale. My drive is brick-paved, and that's plenty even enough.
Regarding tracking outside of manufacturer's settings, that's fair enough. Typically a bit more toe-out will make the car turn-in a bit sharper. My car is actually specified with a huge amount of toe-out, but it is very nose-heavy and understeery. The problem is tyre wear. Part way through its life, the manufacturer rowed-back a bit on the toe-out. I tend to set it with a bit less toe-out than specified.

 

[Avocet]

Yes, here it is with the worst bits underlined.
I suppose anyone satisfied with that may well have not bothered with the steering wheel position.

I will do as you suggest and see how it turns out.

View attachment 280096

OK, so that doesn't look too bad to me at all. If I'm reading it correctly, (and assuming the sign convention is the same in the country it came from as it is here), toe-in is positive and toe-out is negative. So you're looking for a total front toe-in of 1.1mm, give-or-take 0.5mm, which means a total toe-in between 0.6 and 1.6mm. Your "finished value" has a total toe-in of 0.5mm so it could do with an absolute smidgen more toe-in. Frankly, I wouldn't expect to be able to feel that if I were to drive it. Your front tracking is set a bit closer to parallel than specified, so I guess the tyre wear will be minimised, but it might feel a bit vague in the straight ahead position?

The next row, just shows the figures "per side" - which, perhaps unsurprisingly, should be equal. In practice, of course, to go straight, you'll just end up tuning the wheel until they ARE equal.

You have 9 minutes of a degree more positive camber on the right than on the left. Is it a left hand drive car, by any chance? It's unusual to see a car with positive camber (wheel leaning outwards at the top when viewed from the front), but if that's what they specify, then fair enough. On most suspension geometries, it goes more negative as the wheel moves up on its spring, so it's possible that the left hand side is sat fractionally lower than the right? In any case, camber might not be adjustable on that car? You can see that the specification is for anything between half a degree positive and half a degree negative, so it's within spec. Likewise, caster and kingpin inclination (which is just as well, because they're unlikely to be adjustable).

Your rear toe, is worrying though. You're running a LOT more toe-in at the back than specified. Did they not say something about that?! Your total toe-in at the back, should be just less than a millimetre, (0.9mm +/- 0.5mm) and it's actually nearer 3mm! If it were my car, I'd start trying to sort the rear toe before I did anything else. I'm not familiar with the rear suspension on a mid 1990s Previa, but is it semi-trailing arms? Sometimes, they have "snail cam" bolts that can be slackened off and rotated so that they twist the arm on its rubbers to face more inwards or outwards to change the toe. Make sure that the rubber bushes in the arms aren't worn out, before you do anything else, because otherwise, you'll be wasting your time trying to set the toe.

I think that's where I would start if it was my car. Sort the rear toe and then see where the steering wheel sits. If it's still crooked, a small tweak on the front toe-settings should sort it.