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Equipment > Accessories > Drivetrain Misc / Small Parts > Seatpost


Some carbon, steel, and titanium bikes are made with an integrated seatpost (ISP) design. These systems have an extension above the toptube that take the place of a seatpost and require a mount system that allows the rider to install a saddle. Hence, the Ritchey WCS Seat Mast Topper, a set-up developed for specific outside diameter round extended seattubes. Ritchey has offered this system in 3 sizes, and it is currently available for 30.25mm and 34.9mm round OD masts.

The seatpost comes with a standard 1-bolt clamp to fit all 7x7 rails and Ritchey does offer clamp kits for all other rail diameters/shapes. Please be sure to use the correct size for each saddle or you may experience slippage.

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  • ISP-style seat mast topper for round seattube extensions, featuring Ritchey's single-bolt rail clamp design
  • Material: 2014 Alloy
  • Total length (for tube depth): 70mm (minimum insertion: 32.5mm
  • Offset: 25mm (30.25mm and 34.9mm diameters)
  • Single seat collar bolt design
  • Saddle clamp: 7x7mm round saddle rails (simple clamp plates options sold separately for oval rails)
  • Torque specs: Saddle clamp 12Nm (max) / Seat collar torque: 5Nm (max)
  • Offset: 25mm (30.25mm and 34.9mm diameters)
  • Diameter options: 30.25mm 34.9mm
  • Color: High-polish black, WCS logo
  • Weight: 116 grams (30.25mm/25mm offset)
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