I'm asking because I don't know. So educate me.

1. Why does wheel/tires need balancing? If it's a perfect 360 degree circle, why would it need to?

2. Wouldn't adding weights to a wheel actually throw off the balance of the wheel?

3. How do they know WHERE to stick on the wheel? Again, if it's an even 360 degrees.

4. If the wheel is somehow not balance (forget the 360 degree theory) then wouldn't the balance change depending on the speed of the rotation? In other words, how fast are they balancing the wheel? 75mph? 80mph? 40mph?

5. What does on in the machine that they use to balance the wheel?

Thanks

 

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wheels are generally balanced, tires are not due to support, seals, and valves but anyhow the place them on a device the weighs them while spinning, and where ever the most pull is indicated the equal amount is placed at the other side.

 

Due mainly to manufacturing tolerences, there is not the exact same composition and density of rubber or metal all the way through the tire. You add weight opposite this to counteract the defect, Without a proper balance, the heavy spot has more inertia outwards than other parts of the tire and the wheel will not spin freely and smoothly. It will be constantly fighting itself and the suspension. The machines that measure the balance can feel where there is a weight difference, and it instructs the user to place a counteracting weight of approxamately the same weight opposite the problem. Before these fancy machines, they used to loosen up the wheel bearings with the wheel on the car and turn the wheel little bits at a time to see if it started to turn on it's own...if it did, the part that eneded up at the bottom was the heaviest point, so they added weight opposite of that so that the wheel would stay wherever they put it (i.e. equal weight all around the circumference of the wheel).