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Gemini Alsak Specialized Tarmac SL8 Seatpost
April 15, 2026Price range: $449.99 through $489.99
Ultralight carbon fiber seatpost for Specialized SL8 frames
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Gemini Alsak Specialized Tarmac SL8 Seatpost
The Gemini Alsak Specialized Tarmac SL8 Seatpost is one of the lightest seatposts in the world, made from forged carbon fiber and using titanium hardware. Designed and manufactured in Barcelona, the Alsak features a unishell body. This keeps weight to a minimum while allowing it to be strong enough for road riding and racing. In addition, Gemini’s saddle clamp is compatible with both round and oval rails.
The Alsak seatpost comes in a variety of options and is specifically designed for Specialized Tarmac SL8 frames. You can choose from 300 mm and 350 mm seatpost lengths. These seatposts feature Gemini’s UD finish that is available in both gloss and matte variations. The Alask is also available with Gemini’s lightweight carbon layup. The lightweight carbon layup is Gemini’s lightest option, but is not recommended for riders that weigh over 90 kilograms.
Please note the Alsak seatpost cannot be cut and the minimum insertion depth must be followed.
Compatibility
- Only compatible with Specialized Tarmac SL8 frames
Specs
- Material: Carbon
- Offset: 0 mm
- Weight: 300 mm Lightweight - 91 grams | 350 mm Lightweight - 100 grams | 350 mm Performance - 131 grams
Q&A
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