Just bought a used Spec Roubaix for purposes of long training rides. Wheels included were old and heavy, so I found some used Reynolds Assault Limited Clinchers online. These have an internal rim width of 20.8mm according to Performance Bike. I can't find any info on max appropriate tire widths. Brake and frame clearance allowing, I would like to run 28c or even 30+ tires for comfort purposes. Any suggestions? Thanks in advance.