What is an alignment


#1

What exactly happens when a car becomes out of alignment? I mean what has happened to the steering system to cause the car to not drive straight and when it is aligned what all is done? Also since it can be nocked out of allignment pretty easily like hitting a pot hole, how often should you have it done?


#2

Rather than thinking someone might type it all up, I would suggest that you review this:

…which is just one of many sites that you can find.


#3

Alignment is setting the angles (very small angles) of the tires. Looking down from above, the tires should be almost exactly straight ahead with each tire turned in to the middle of the car a tiny bit (0.10 degrees or so - I SAID tiny). That is called toe angle. If you look at the front of the car, the tires may lean in or out a tiny bit at the top. That is called camber angle and it may need to lean out (positive camber angle) or into the center of the car (negative camber angle). That number should be 0.5 degrees or so. The third one, you can’t see but it is how far the steered wheel’s suspension leans back. That is called caster angle and can be 1 to 6 degrees or so.

All 4 tires need to be set to the manufacturers specs so the car goes straight down the road with the steering wheel centered and doesn’t wander all over the place or wear out tires at a wicked pace. If your car doesn’t do any of these and you haven’t hit anything hard lately, you don’t need an alignment. If you can take your hands off the wheel on a flat road and the car pretty much stays straight, then things are likely A-OK. IF you just got the car, and you are buying new tires, consider having it checked. You can align it wrong and still have it go straight but prematurely wear out those new tires. Whew - complicated subject


#4

The steering and suspension takes on some big forces even without pot holes. With pot holes, whew, it is a wonder it works at all. The metal parts holding it all together can bend an deform just hitting one pothole. The car makers know this will happen, so they provide various adjustable gadgets on the suspension and steering components to turn this way or that to compensate for something that got bent or deformed, allowing the wheel alignment shop to bring everything back into the same orientation it was when the car was new.

It’s like if you bend a paperclip out straight, if you know what a paperclip looks like you can bend it back into a paperclip.


#5

What exactly happens and why it makes the car not drive straight can be complicated. Your suspension and steering systems operate on a number of interrelated arcs and angles. If the three axis described my Mustangman aren’t properly adjusted, the angles can interact to cause other than the intended effect. Add to that the forces involved, for example your wheel’s axles are being pushed backwards from rolling resistance as the car rolls down the road, and things can get weird.

And there are other variables. If your steering wheel is not centered before doing the adjustments, it can “off center” your steering rack, such that its ball joint that connects its end links to the steering knuckles (or tie rods) isn’t operating with the tie rod end arc as it should be, and you can get “bump steer”, which is steering inputs induced by travel of the suspension. I’ve personally seen alignments where the wheel was cocked after the work, and that is not correct. In the old days, bad shops would pull the steering wheel and reinstall it, still not correct, but with airbags that’s not so simple.

The subject of what exactly happens gets complicated. I commend Mustangman for his simplified explanation. I’m unable to describe things in a simple manner.


#6

Regardless of how it is done, we do it way too often. The key is to recognize when your car does need one and have it down by competent shop the very few times it really needs it.


#7

I am afraid mine really needs it, I am taking it in tomorrow to make sure it’s not something worse. My van wishes to go left. If the stearing wheel is straight then the van goes left, I have to keep the steering wheel turned to the right to keep going staright. I am hoping it’s just badly out of alignment, but from what I have read it could also be a bad ball joint or tie rods. And with my total lack of car knowledge while I know those both are very important, I am not real sure what they do exactly and how they impact the alignment on a car.


#8

Besides a car not driving straight, what are some other signs you might need to replace your ball joints or say the tie rods? How hard is it to replace those two items? Besides those two could there be other things (outside of hitting pot holes and such) that can cause the alightment to be out of whack?


#9

@bertand, Tie rods are pretty easy to replace, ball joints, depends on the car or truck. Some need the suspension arm replaced because the ball joint is part of the arm. Some can be replaced by pushing the joint out and pressing in a new one. Both bad tie rods and bad ball joints are determined by looseness in the joint itself. That can show up as a vibration through the steering wheel or the tendency to wander all over your lane. Either could be bent, too, causing your pull to the left. Bent is bad, the next step is to break - and that will be bad. Alignment is (nearly) always done after replacement of either. I agree with @dagosa here, alignment is done waaay too often. but once it is done properly should last you at least through a set of tires if you don’t hit curbs.


#10

There is a slight wobble in the steering wheel but was told last week that was due to a tire that is nearing needing replacement which will happen at the end of the month. Other wise outside of the vans desire to veer to the left there is no sounds coming from the front end, no noticable shaking or such. I had brand new brakes put on last week and “thought” had there been any issue with the tie rods or ball joints they might have seen that since new rotors were also put on the front but maybe not. Have an appointment tomorrow to have the front end checked out.


#11

Most alignment requests that I see are due to a failing tire that is causing a pull. Since the shop told you you have a bad tire you should take care of that first.

If you take the vehicle in for an alignment with the bad tire on they will perform the alignment (usually minor adjustments) and after road testing they will have to move the bad tire to the rear to correct the pull. You would be better off spending the money on a new tire.


#12

My plan is to add new front tires and align.


#13

Sometimes if I’m not sure if the tire is causing a pull or not, after I’ve verified the pressure is exactly the same in all four tires, I’ll just switch the two front tires, right to left and left to right, see if it pulls the other way, if so, then it is the tire for certain. I don’t think it is a good idea to change tire rotation direction for any extended mileage so I only do that as a test. I always put the tires back to rotating the way they were.

OP: Tie rod, tie rod ends, and the ball joints are what hold the suspension and steering components together. They sort of form the skeleton of a box-like structure. Imagine if you made a box kite for example, that is sort of how they are arranged. But, unlike a box kite, they have to move with respect to each, for the steering function, and that the passenger compartment moves on springs w/respect to the wheels. If there were no need for them to move, the manufacture would just weld them together and make it a rigid structure, but since they have to move both in respect to each other and w/respect to the wheel motion, they have to be connected together with movable joints, called ball joints. Sort of like your own elbow and hip joint. Other parts not needing quite as much freedom of motion are connected with gadgets called bushings.


#14

Well found out car in good condition just four bad tires and a car really out of alignment. So next week we replace the front two and align and at end of month we replace back two and postpone rear shocks till march.