Some will go to the extra trouble of giving a frame a shot of WD-40. The Gruven frame uses a very special material to form the roller endcaps. They are usually chromed to inhibit corrosion. The Gruven frame uses high quality stainless steel. There is no coating to wear off and it will never rust.
Stainless steel is much stiffer than mild steel.
It rolls smooth and straight without a sound. It's a solid predictable feel you will notice the instant you make your first pass. Either they are so hard to clean they don't get cleaned and begin to bind and skid, or the flimsy bearings simply wear out and begin to squeak and rattle. I've seen roller cages fly completely off when you go to remove a roller cover by hitting a frame against a bucket. You can easily get to the roller endcap bearings and clean them in seconds.