Gemini Alsak is among the most advanced and performing seatposts on the market, it is also among the lightest (starting from 69 grams) and undoubtedly among the most beautiful and well-finished in terms of aesthetics with a racing and elegant look at the same time. It can be used both on the road and off-road (MTB, Gravel, Cyclocross).
It is a vertical type seatpost (without setback, 0 mm offset), made in various diameters (27.2 mm - 30.9 mm - 31.6 mm) and in various lengths (250 mm - 300 mm - 350 mm - 400 mm). On request it can be made up to 500 mm long.
The Alsak seatpost cannot be shortened as it has an optimized structure to be tightened in a limited range, for this reason it is essential to measure your seat height (from the end of the frame to the saddle rails support surface) and consult the table below to choose the correct size.
It is an entirely monolithic structure made of carbon fiber, this type of construction offers several advantages and allows for a much more resistant and high-performance product. Since there are no interruptions, the fibers work homogeneously without stress points with a linear and progressive behavior by distributing the loads over a larger surface. This type of construction avoids constant and localized stresses and considerably prolongs its fatigue life.
The main tube of the Alsak seatpost is made with Mitsubishi MR70 fibre, the most modern and high performance of intermediate modulus fibres, developed for the aerospace sector and able to allow for maximum optimization of the strength/weight ratio.
The cradle on which the saddle rests and the clamps that lock it are made of forged carbon fiber with a technology derived from the world of hypercars. Over 100 tons of pressure and heat compact the short fibers to make them super strong and allow for more complex shapes. The result is highly optimized structures with large contact surfaces and absence of sharp edges which facilitate coupling even with saddles equipped with carbon fiber rails. Compatibility is guaranteed with all types of saddles, both with round and oval section rails.
The clamping bolts are in grade 5 titanium with a black anodized finish. Even the threaded bushes on which they are screwed are made with the same material and finish to thus avoid possible galvanic oxidation phenomena and guarantee maximum resistance and reliability as well as durability over time. The bolts have rolled threads and a forged head with double coupling (internal Torx and external hexagonal) thus allowing tightening and adjustment in any situation.
If the materials used are very important, the way and technology with which they are used is even more so. The Alsak seatpost is made with monolithic technology (monocoque) and is characterized by a "sandwich" structure with layers of bidirectional and unidirectional UD fabric. The twill fabric is characterized by greater resistance to impacts and delamination while the unidirectional fabric allows you to make the most of the structural and mechanical properties of the fibre. There are many cuts of fabric that make up the final structure which is highly optimized in terms of shapes and thicknesses to guarantee the maximum possible resistance/weight ratio.
Then there are some construction details that are not visible in the finished product but that make the difference in terms of quality and performance, such as the use of specific bladders with the same internal shape as the single seat tube. The bladder is a sort of vacuum bag in silicone material which is pressurized and contributes to the compaction of the fibers during the molding phase. If its shape perfectly copies the internal surfaces, there will be no wrinkles, folds or accumulations of resin, with the result of having a lighter, more resistant and safer final object, without weak points.
Talking about safety, the Alsak seat post has brilliantly passed both laboratory tests (flexion, maximum resistance, fatigue, impact) and those on the competition fields and obviously those required by the standard (ISO 4210-5) . Its monolithic structure, the use of the best materials and the best technologies, make it truly highly safe and performing like no other on the market!
In addition to laboratory functional tests, quality control and finishing are equally important, after being produced, each Alsak seatpost is tested with ultrasound to identify any production defects and is then finished by applying a special very resistant ceramic paint which it also protects it from UV rays as well as making it even more beautiful from an aesthetic point of view.
The Alsak seat post is made in two different versions: "Ultralight" and "Performance" which provide for a different structure and lamination which entails different characteristics and performances.
The Ultralight version is characterized by an extremely low weight (starting from just 69 grams), which makes the Alsak seatpost one of the lightest on the market. The maximum weight limit allowed for the biker is 90 kg. It is a seatpost suitable for those looking for maximum lightness and superior comfort.
The Performance version is also characterized by a competitive weight (starting from 88 grams), but above all by greater rigidity which makes the seatpost more reactive, the reinforced structure makes the seatpost even more resistant in the event of a fall. It is therefore the most suitable version for agonists looking for maximum performance without compromise. The maximum weight limit allowed for the biker is 120 kg.
The table below summarizes the weights of a 27.2 mm diameter Alsak seatpost in the various available lengths and versions. The weights refer to seatpost with UD matte finish, are indicative and subject to variations and to a normal tolerance of 5%. The versions with 12k finish are heavier as are obviously the seatposts in larger diameters (30.9 and 31.6 mm).
We remind you that saving weight on the peripherals (such as the seatpost) is very important, as it allows you to lower the center of gravity for greater stability and handling and also allows you to minimize the energy dissipated to counteract the pendulum effect of the bike which swings sideways during the thrust (especially when pedaling out of the saddle). These are details that at certain levels can make the difference and that should not escape an attentive and demanding biker.
The Alsak seatposts are made with the last external layer of UD or 12k unidirectional fiber, the finish can be chosen as matt or glossy. The 12k texture and glossy finish add some weight over the UD texture and matte finish. The graphics are white and are decals placed under the transparent protective paint.
Upon request, and with a surcharge, it is possible to have customized seatposts in terms of aesthetics (texture colour, graphics, special paintwork). Contact us for more information about the possible customizations and the related costs (the cost of the customization varies according to the type of customization and the number of colours).
Alsak seatpost is covered by regular 2 years long warranty but there's also a "crash replacement" policy that allows to save 50% value if you need to replace the seatpost after an unfortunate accident (or for any other case not covered by the warranty). To take advantage of the crash replacement discount you need to send the damaged seatpost directly to Gemini and provide them a proof of the purchase.
All Gemini products are proudly designed, engineered and produced in Barcellona, Spain!
- Weight :
- From 69.5 gr. (Ultralight 27.2 x 250 mm) ; 88 gr. (Performance 27.2 x 250 mm) - tolerance +/- 5%
- Construction :
- Length :
- 250-300-350-400 mm
- Tube Diameter :
- 27.2 - 30.9 - 31.6 mm
- Offset :
- 0 mm
- Tube Material :
- Mitsubishi MR70 Carbon Fiber
- Hardware Material :
- Forged carbon fiber
- Finish :
- UD or 12K, gloss or matte
- Graphics :
- White, under clear coat
- Bolts :
- Special CNC Grd5 Titanium
- Use :
- MTB, Strada, Gravel, Cross, Triathlon
- Fitting :
- With all saddle rails (round and oval both)
- Max rider weight :
- 90 kg (Ultralight) ; 120 kg (Performance)