Is it normal to hear debris or stuff rolling around in your rear (stock) tires?? Do they put stuff in them from the factory to assist with balancing?? I have not took the tires off the rim to check it out, yet. Sounds like small rocks/marbles rolling around in there.

 

yes it is normal they are little pieces rubber i dont know what they are from
nothing to worry about though

 

Not unusual!

 

I have the same thing w/ my 400ex. I thought it was a rock at first, but no worries.

 

It is the lubricant that is applied to the beads for mounting. It rolls around in the tire and forms hard *****.