Nodular iron rigid standards are standard on the 637 Disk. These massive straight standards direct thrust forces up, to prevent twisting the gang tube when you encounter field obstacles. A square gang bolt gives the disk gang extra strength. Welded steel spools add protection. Extra-long triple lips on the inner race, combined with a wide seal between the outer race and flange, flex to resist wear, keep dirt out and help maintain lubrication.
Bearings are self-aligning and greasable for longer life.
And they're backed with a two-year warranty. Either way, these scrapers direct soil and residue backward, rather than up toward the disk gangs where it can interfere with the disking action. Wheel modules are maintenance-free. Unlike the joints in other disks that wear over time and distort depth by increasing play in the rockshaft, John Deere disks feature maintenance-free wheel modules. And there's no wear in the joint to affect depth.