How can I determine a bent axle? check for runout as it is spinning?
check to make sure there is nothing stuck between the rim and the hub,making the wheel shake
If axle is bent, wheel will wobble
Take a jack stand and place it next to the offending axle. (Remove the wheel first.) Take a piece of chalk in your fingers while resting your hand on the jack stand, and have someone turn the axle while you hold the chalk near the axle. Turn it one revolution. If you get no mark, move in a little closer. Do this until you touch the metal. (On the outer edge of the axle, the rounded edge.) If you hit in one place making a small mark only, you are out of round.
