I understand that hitting a bump will cause the front wheels to be knocked out of alignment. However, I do not understand why. Especially the toe, If the tie-rod end is protected with jam nuts then how does it move? Does it damage anything when it moves?

Thanks.

Now that I look at it, this should be in the wheel and tire forum...ohwell.

 

If your wheels are changing alignment with every bump you have more problems than you realize...

 

Bushings. Even the steering rack is mounted with rubber bushings.

And yes, over time, the bushings will be stretched, worn, and torn enough to warrant replacement.

 

No but if you hit a bump hard enough and that is when it gets changed...or lets say you hit a curb. This is just for my own knowledge, this does not happen to me.

When I buy new tires I could opt for a "thrust alignment"...they do a bunch of adjustments with toe, camber, yadda yadda. MY question is why do these things get knocked out of their spot if everything is tight?

 

After quickly searching what a thrust alignment even is, um, that really doesn't seem to apply to your car since you don't have a car with a live/dead rear axle.

You want a proper 4 wheel alignment. Toe is what matters most, but the other values can provide an indication of issues before they become problematic.

Are you asking why something held in place by rubber designed to deflect as needed, can shift over time?

There's more to it than that, but I was keeping things simple. Metal deforms, vehicle weight and ride height subtly changes, not everything is locked in place in such a way that it can't shift position even if the bolts are fully tightened (go look at how the rear toe is set for your car for a perfect example of this), parts wear, and the list goes on and on...

If your alignment changes too quickly (where "too quickly" varies based on how the vehicle is used, road surface conditions, etc...) then you'll want to find the cause. However, all cars have their alignment drift over time, and it is expected and normal.

 

Because wear and tear.

 

metal stretches/deform, bushings become eccentric, balljoints develop play.

 

This is all fine and dandy, but he is now talking about hitting curbs. What do you think is going to happen? What would happen if you drove your vehicle off a cliff or maybe plowed into the back of another car? Vehicles weren't designed to do this on a daily basis. They were however designed and tested for bumps, potholes, curves, ect in the road. As with any mechanical object - these stresses over time wear parts, even the entire vehicle. If you are extremely hard on your vehicle or make upgrades without supporting modifications it is possible to start tearing the frame/unibody apart.

So, back to alignments - any moving parts will wear. When it comes to curbs - anything that can be bent or broken. It's really that simple.

 

even a pothole in the road i hate it too but it happens

 

Alright, thanks a lot for all your responses. I see what you guys are all talking about.