What is the difference between a wheel alignment and tire balance?

Question

My car starts to shake when I get on the interstate going about 65 mph.

Answer 1

Rims and tires have heavy and light spots in their circumference which cause them to rotate unevenly resulting in shake and vibration. Balancing, adding weight opposite the heavy spots, will correct the problem. Front end alignment is a condition where the front wheels are not aligned so that they will travel in a straight line. If alignment is perfect then turning loose of the steering wheel, while driving on a straight level road, should see the car continue in a straight line. If out of alignment the car would pull to one side or the other. Seldom will wheel alignment cause shake. The most common result with improper wheel alignment is uneven and/or rapid tire wear.

Answer 2

I'll let you in on  something that has happened to me 3 separate occassions. My car would shake when i would get going over a certain mph, normally over 50 and often over 65.

I took it into the shop and they alligned my car and did the tire balance thing. Always explaining how good my tires looked. Then i would finally get my new tires and the thing would stop shaking. It was always a simple new tire.

BUT, that isn't the normal case, but it can be a problem. Even if a  tire doesn't look like it.

The other guy explained what those two meant already. Tire balance they take and fill your new tire on the rim and then place weights around to balance out the tire completely. To make it drive perfectly on the road.

Wheel alignment is about aligning the part under your car that holds your wheels on. To make sure that isn't throwing off the balance of the car causing it to shake.

I added in my two cents only because not all understand the more technical side of it and need simpler and more understandable answers. Thought he first guy who answers was spot on.  

Answer 3

A wheel alignment checks/corrects the toe and camber adjustments of the wheel ( the angles that the wheel sits ) while a tire balance only ( as the name suggests ) balances the wheel and tire.

From the sounds of it, you have a wheel balancing problem.  An alignment would be needed if you were to notice irregular wear on the tread on one or more of your tires.

Answer 4

When it shakes the tires needs balanced.  When it pulls the tires need aligned.

Answer 5

a wheel alignment how your wheels are made to be perfectly in line with the car  vertically and horizontally and made parallel with each other.

Tire balance is adding weights to the rim in computer designated spots so that when the wheel spins its perfectly balanced and spins with equal weight on all degrees of the circle.  

Your problem sounds like a bad wheel balance.  

Answer 6

LOL, my toyota van too.  Ford's resonant frequency is like 63.

The reason why is shakes is because at that speed, your car is in a resonant frequency. Resonant frequency is the natural vibraton frequency of the system.  It's like a tuning fork, if you smack it, what pitch or sound would it make?

So what causes this?  Your tire is  moving up and down OR wiggles left and right.  In some very bad cases, it does both.

How your car reacts to alignment or balance depends upon your suspension system setup, age/milage, Load, and road conditions.

so lets look at what causes this.

Wheel alignment.

If your tires are not pointed in the direction  that your car is traveling, the wheels are actually moving in the direction of the toe, applying stress to the suspension (compressing a spring) as it rolls, lose traction, then gets pushed back to the orginal position.  This causes some vibration and lots of wear.  This would also make your steering wheel shimmy left and right.

Wheel out of round.

This would be like riding on a ripply road. Your axel gets pushed up (bump) and let go (rebound).  With this condition, the vibration doesn't necessarily get worse with increasing speed, but the frequency does increase.  There is a speed where the vibration is at the greatest amplitude but gets better with increasing speed.  According to Goodyear, our car should not notice a tire out of round if the run out is less than the thickness of a dime (1mm or .040 inch)

wheel out of balance.

The behavior is just like a wheel out or round except there is a minimum speed when the centripital force acts like the wheel out of round.

In most cases, tires are never concentric nor balanced.  We rely on the supple tire and suspension to take up the imperfection in the tire. but if you lose a tire weight, you will have a nasty vibration.

If you car makes noise that is dependant on speed and direction of turn, and the sound is not always consitant with speed, you have a problem with your main steering joint or knuckle.

Hope this helps.