About 4 weeks ago I treated myself to a set of 4.5" diameter Kreitler Challenger rollers. I've been recovering from double hernia surgery and doing some low resistance spinning on a set of cheap PVC rollers I'd picked many years ago at Performance bike. They were very noisy and rough riding. The Kreitlers are expensive, but silky smooth and very quiet. They also have a simple tooless wheelbase adjustment system that doesn't require removal of the front drum. Well worth the money IMO.