# Bouncing tires

1. Apr 11, 2007

Car tires seem to bounce very well however they are easily unbalanced and tend to tip over very easy. If you were to connect say 2 or 3 similar tires together and then dropped it, it should prevent the tires from tipping over and stop bouncing. This will however make the mass significantly larger. Since the mass is larger, will this effect the bouncyness of it allowing it to bounce less then a single tire?

2. Apr 11, 2007

### ShawnD

If you have 2 tires, like a car axle, and they bounce out of sync, what happens is that one tire is going up while the other tire is going down. Having one side go up and one side go down means the axle now has a center of rotation, and having both gravity and bounciness act in the same rotational direction is called a "couple". You'll lose a lot of energy in this "coupling" effect.

Short answer: I think 1 tire would bounce better than 2.

3. Apr 11, 2007

### Staff: Mentor

Since the tires are identical, the height two tires bounce to is the same as the height one tire bounces to whether the tires are connected or not.

Stability while bouncing is a completely separate issue and coupling due to out of sync bouncing is a separate issue, though since we don't know what your point is, they may be relevant....