Pinch roller size ? VS300i

One of my wheels gave out and I'm in need of some new wheels , I have the service manual but I can't find the size anywhere . can anyone tell me the common size of the pinch roller wheels ?

 

Thanks , are these parts something that need to be replaced often ? mine have been there since 2013 .

 

I'm looking for the center wheels , any chance you know the part number ?

 

Thanks Jim , wow those inner rollers sure are expensive .