or you can bring your vehicle for an alignment and ask them.
1 Like
With modern electronics itâs a pretty simple matter to use lasers and other sensors to determine the absolute orientation of each wheel.
My phone can measure its orientation within a degree, so special equipment would be even more accurate.
Have you googled âhow does wheel alignment workâ, and read the articles in the resulting links (no videos)? They would explain a lot.
Tester
1 Like
No, there isnât. An MRI machine costs >$500,000. There isnât a âcheaper wayâ to do an Mri. Similar principle.
3 Likes
And even shops with the good equipment donât necessarily do the best jobs. @CapriRacer is our tire expert, and he recommends that shops aim for the middle of the spec, not just check that itâs within the total allowable range. I donât know how I could achieve that accuracy in my garage on a 4 wheel alignment.
3 Likes
I have been doing my own 4 wheel alignments for over 30 years. so hereâs what I do to square up the toe, front and rear.
-
You have to find a parallel reference on the side of the car. The pinch weld is straight and can be used as a reference to set up string lines parallel to the car. I use 4 jack stands to set parallel strings on each side to measure toe angle at each wheel. Measure to the same point on each wheel rim, the same height off the floor to eliminate camber angle distortion. It helps if the car is up on a couple of 2x 12s under each tire so you can get under the car to set toe and re-check the measurement. This method will zero out your thrust angle, too.
-
Either buy a camber gauge with a built in spirit level or electronic angle finder that registers on the wheel face or build one. The angle finders are cheap. I added one to my old spirit level model. But reference to the wheel with the car on the ground on a flat level surface, wheel pointed straight ahead.
Caster angle is the Camber 20 degrees turned out minus the camber 20 degrees turned in times 1.5. But you need slip plates for accuracy. Caster isnât so important as a number as being equal side to side. If the car leads left on a flat road, you have more caster on the right side than the left side. Fix one or the other.
2 Likes
And youâre also a suspension design engineer, right @Mustangman ? So OP, please take that into accountâŠ
5 Likes
Well, yeah, I am a suspension design engineer. I do understand this stuff. Still do the Mustang and Truck myself, both with solid axles, so 2 wheel alignment is fine.
I doubt even Iâd try and do an alignment on my wifeâs Audi A4 Quattro even though Iâm retired and have lots of time.
Jack it up⊠remove the under panels⊠block it up⊠level the blocks⊠run the string lines, adjust, check, re-adjust⊠road testâŠjack it back up to put the under panels back onâŠ
So much easier on a Hunter machine on a drive on lift⊠sipping coffee in the waiting room!
4 Likes
Iâve realized there are two kinds of people in this world: those that value their time, and those that value their money.
I used to be a âmoneyâ person. Then one Saturday afternoon, as I was lying under one of my cars changing the oil, and the oil was running down my arm, ruining my shirt and staining my garage floor⊠I suddenly realized the $10 I was saving in âcostâ wasnât worth the mess, labor, and time away from my young children. Ever since then, Iâve been taking my car to the mechanic for an oil change, where I sit in his warm/cool office, and drink his coffee.
Your results may vary, thoughâŠ
4 Likes
I was pretty much a diy guy, wanted to change the plugs in my 03 Trailblazer, opened the hood and could not even find them.
1 Like
Bah. Get me a kitchen knife and a camera. Weâll see whatâs goinâ on in there!
3 Likes
not sure where you found this âbig moneyâ thing?
my local âlesser expensiveâ brand dealers (read Honda/Nissan/etcâŠ) regularly advertise $90-100 alignment specials, and every time I used the service, it was done right and print-out of all the angles showed âbefore and afterâ and corrections were made on all what is needed for the same flat fee
are you not inventing the problem where one does not exist?
you happen to own expensive/luxury car⊠ok, donât cheap-out on maintenance
3 Likes
Itâs possible to do your own alignment. At least to measure what the alignment is. If you have more money than time, probably doesnât make sense. But if you just want to see if you can do it yourself, I say good for you for wanting to try the experiment.
Iâve never done it (except for toe on my truck), but have seen several articles. For toe and camber, first off you have to figure out a way to create reference lines which are parallel with the length of the car. You know where the center of the wheel hubs are, right? So you can use those. Note that the front axel length (i.e. the lateral distance from hub to hub) may not be exactly the same as the rear, so you have to take that into account. Once youâre able to create accurate lines which are parallel to the car, toe, applying a little geometry, relatively straightforward. A quick way to measure toe, mark a spot on the two tires, plumb-bob where that spot hits the ground when the spot it at the front of the wheel, then push the car until the spot is at the rear of the tire, do the same thing. [Flat , level ground is required, and tires properly and equally inflated.]
Camber can be measured with a bubble level. Some cell phones have this capability. You need some sort of offset fixture so you can reference to the rim, but thatâs a simple enough problem. It seems like the best way measure camber is with the tires installed and the full weight of the car on them.
Caster is tougher. You have to be able to turn the wheels to measure caster, without messing up your reference points. One solân , figure caster is ok and donât worry about it. If you want to measure caster, there are simple kits you can buy that provide everything you need.
Question 1, toe in/out is measured using the front tires only. It is their relationship to each other. However, the toe of each front tire is measured against the rear same side tire so that the steering wheel is centered. Make sure the steering wheel is centered at the start and yu may have to take in account that the rear may have wider tires than the front and the track may be wider or narrower too.
Question 2. I use a 2x4 across the front of the tires and place a straight edge against the side of the tire and mark the 2x4 on each side. Be careful with raised letter tires as they will throw off your measurements. Then I move the 2x4 to the rear of the front tires and push it up against them. I line the straight edge to one line. Then on hte other side I make a new line with the straight edge. The difference between these two lines is the toe. If the line from the front is inside the line from the rear, it is toed in.
Question 3, you jack up the car from the ball joints or on the lower control arm just inside the ball joints. You will need four jacks and when all four wheels are jacked up, the car must be level, side to side and front to back. Then you can remove the wheels and measure the camber.
Now if you have the four jacks and a spot that you can use to get the car level, then you need 2 pieces of 2x2x1/8â angle iron 20â long and two more that are about 8â long, 4 pieces of 1/2" threaded rod about a foot each and 8 1/2" nuts. Make a square around the car (rectangle), drill 1/2 holes at the intersections of the angle iron and put a piece of threaded rod through, with the two nuts hold it together. Square up angle iron so it is the same distance away from the center of the hub on each end of the car and adjust the height to the center of the hub using the nuts and threaded rod.
Now you can do a 4 wheel alignment NASCAR style. Unless an alignment rack has just been calibrated to NIST standards it will probably not be as accurate as this jig.
It would have taken me all day and many pages to say that. One of the biggest fctors ow how a tractor trailer drives is alignment. A properly aligned and suspended car or truck lets you feel what the wheels are doing and when roads get slick you can tell by feeling the slip. An out of alignment vehicle always has the wheels slipping against each other all the time.
1 Like
As you can see anything can be done DIY if you have enough time, materials, resources, and ability. But where I work you can get your Audi aligned properly for $99.95. I canât see going through all that work in your driveway for that much.
Today I checked in a customer with an Allroad that had an alignment at a local tire shop. He said the car drove worse after they were done. All the readings were âin the greenâ but they were out of center far enough that the car had a right pull. Ww fixed it up perfect.
That is what I told the OP earlier when he called me out for wanting to pay for everything and not learning to do any DIY.
After a repair I have set the toe with a tape measure until I could get the vehicle on the alignment rack. In some cases that was several years, 1/16" of toe doesnât make much difference in tire wear unless you drive a lot.
Yes as I age I have come to appreciate the quality of waiting room coffee.
Just thinking, in the last couple of years I have done things Iâve never done before. Hired a roofer. Hired a painter. Hired a guy to install gutters. Hired a plumber. Great fun watching people work.
What alignment machines do is make it easy to measure. The best machines will calculate where the wheel is relative to the other wheels (After all, itâs all a bunch of math), and show what the the toe and camber are. They use slip plates to get the caster.
A DIYâer can do all that, too, but it requires much more time and effort.
I use to do my racecar and found some short cuts.
One is a trammel bar. (Google it!) Second is a camber gauge.
And once I established the centerline of the car (even marked it!), I did all 4 wheels for squareness and didnât need to do that again.
I can easily see why a DIYâer would want to ⊠ah ⊠DIY. That way you KNOW!!
And lastly - as has been pointed out above - the rear track width is not the same as the front track width (on most cars). Plus rear wheels can have toe - even solid axles!. So donât use the rear tires as a reference. Establish the reference outside the car.