Mine aren't grooved either and my PRW rockers are going on 8-9 yrs or there abouts without an issue whatsoever. I was just asking because if it was so necessary as stated in post #52 by Rat Bastid, why are there so many folks who haven't had a problem running the stainless PRW rockers without grooved shafts (myself included)? And why does B3 sells them if grooved shafts were needed?