Small Engines (Lawn Mowers, etc.): Sears 42 inch deck vibration, miss match, wounder

Question
I have a Craftsman 15.5 HP Lawn Tractor with a 42" mowing deck.  I went to replace the blades with gator mulching and found the star bolt on one of the spindles was damaged. I replaced the entire spindle with a new after market heavy duty version ( other spindle was not replaced) and installed new gator mulcher blades.

When I engage the deck I feel a vibration. I assume the blades are balanced since they are new. Could there be a miss-match between the new and old spindles? The vibration is not to severe but it is enough to be noticeable.

Answer
Did you measure/compare the old and new spindle?

Wounder if it is the Gator blades causing the vibration you are feeling?  You could try changing blades to the old ones to see if it still vibrates.

Let me know if the old blade cause the vibration as well.
Eric