ESJOT Germany Hub Gear Sprockets: Flat vs Dished Replacement 3-Notch Bicycle Cogs

Understanding Flat vs Dished Hub Gear Sprockets: When sourcing replacement cogs for 3-notch internally geared hubs (IGH)—such as Shimano Nexus, Alfine, SRAM, or Sturmey Archer—choosing between a flat and a dished design is critical for your bike's mechanical performance. Flat hub gear sprockets sit completely straight on the 3-spline hub driver, keeping the chain aligned on standard, narrow-spaced single-speed bike frames.

The Purpose of Dished or Cranked Offsets: Dished (also referred to as cranked or indented) hub gear sprockets are engineered with a distinct lateral curve, shaping them like a shallow bowl. This unique design allows the cog to be fully reversible. Mechanics can mount a dished sprocket facing inward or outward to micro-adjust the straightness of the bicycle chainline by several millimeters. Flipping the dish outward also provides crucial physical clearance, preventing the chain from rubbing against wide tire sidewalls or bulky frame chainstays.

Premium Engineering by ESJOT Germany: Renowned worldwide as an industry-standard OEM manufacturer, ESJOT Germany manufactures high-performance 3-notch internal hub cogs, screw-on chainrings, and plug-on sprockets. These components are fully cross-compatible with Enviolo, NuVinci, and Bosch e-bike mid-drive drivetrain setups.

Sizing and Finish Specifications: Every precision-engineered ESJOT sprocket features an exact 35mm inner diameter to sit perfectly on universal hub drivers. Available in multiple tooth sizes (including 16T, 18T, 19T, 20T, 21T, and 22T variants), these cogs are built from hardened steel with specialized zinc-nickel or galvanized corrosion-resistant finishes. Ensure you match your chain width, as 3mm thick sprockets require a heavy-duty 1/2" x 1/8" single-speed chain, while 2mm thick variants fit narrower 1/2" x 3/32" multi-speed chains.