is the brake disc on the kawasaki vulcan 900 supposed to have grooves?

[Mary]

I have a 2009 kawasaki vulcan 900 and I wanted to know if the brake disc on it is supposed to have grooves on it? My front one doesn't have the same grooves and I wanted to know if it was manufactured that way.

 

[PETE]

nope there not meant to have them! means there worn out!

 

[bluff mike]

They get that way from use.