Classic flanged DJ hubs feature a 6-bolt disc rear and non-disc front. With DT’s Ratchet LN system (36t), all of the teeth on each side of the ratchets engage simultaneously every time. This creates much smaller point loads and results in the legendary reliability of Ratchet System hubs. Rear hub includes 12t sprocket. DT Swiss spoke calculator: https://spokes-calculator.dtswiss.com/en/calculator