The Polygon Siskiu D Series is the perfect down-country option for riders looking to blend the lightweight efficiency of cross-country bikes with the capability and versatility of all-mountain rigs. Designed for all-day trail rides, the Siskiu D combines progressive geometry with efficient suspension, making it a great option for riders who want a bike that can climb efficiently yet still tackle technical descents with confidence.

Frame Design and Materials: Strength and Durability

The Siskiu D frame is made from ALX alloy technology using 6061 triple-butted tubing, which is heat-treated for extra durability and strength. This makes the frame lightweight yet tough enough to handle the demands of both cross-country and trail riding. The tapered head tube design improves front-end stiffness and control, while the one-piece linkage system reduces lateral flex in the rear triangle, ensuring smooth and consistent suspension performance.

• Wheel Fit System: Sizes Small and Medium come with 27.5-inch wheels for improved agility and quick handling, while Medium, Large, and XL frames feature 29-inch wheels for better rollover capability and stability at speed. This sizing approach ensures that riders of all heights have the right wheel size for their needs.

Suspension and Faux Bar System: Balanced for Climbing and Descending

The Siskiu D Series is equipped with 120mm of travel both front and rear, providing just the right amount of suspension for tackling technical terrain without sacrificing climbing efficiency. Polygon’s Faux Bar suspension system delivers excellent traction on climbs, keeping the rear tyre planted on the trail, while offering stability and control on descents.

• Progressive Kinematics: The Siskiu D’s updated kinematics include a more progressive suspension curve, meaning it provides a responsive and supportive ride over small bumps but ramps up as the suspension travels deeper, preventing bottom-outs during big hits. The optimised anti-squat design ensures efficient pedalling, even during long climbs.

Geometry: Built for Modern Trail Riding

Polygon has designed the Siskiu D with modern trail geometry to balance stability at speed with agile handling. A slack head angle and longer reach improve confidence on steep terrain and at higher speeds, while the short chainstays and lower bottom bracket keep the bike nimble and responsive on tight, technical trails.

• 27.5-inch Models: The 27.5-inch models, available in XS and Small, feature a 67° head angle and a 75.5° seat angle, providing a comfortable climbing position while maintaining stability on descents. The 432mm chainstays keep the wheelbase compact, making the bike playful and easy to manoeuvre on twisty trails.
• 29-inch Models: The larger-wheeled versions of the Siskiu D (Medium, Large, and XL) also benefit from the updated geometry, with the slack head angle providing stability while climbing or descending at higher speeds, and the long reach adding to rider control.

Down-Country Performance: Versatile Trail Machine

The Siskiu D is designed to be the ultimate down-country bike, blending cross-country efficiency with the capability to handle more technical terrain. This makes it perfect for riders who want a single bike that can handle a variety of conditions—from fast, flowing XC trails to rougher, more technical descents.

• Pedalling Efficiency: The steeper seat tube angle (75.5°) places the rider in an optimal position for climbing, ensuring that power is transferred efficiently to the pedals. This geometry, combined with the suspension design, allows the Siskiu D to excel on climbs without feeling sluggish or overly dampened.
• All-Day Comfort: With enough room inside the frame for a water bottle, and suspension that is tuned for all-day riding comfort, the Siskiu D is ready for long, epic rides in the saddle.

Siskiu D Series: The Perfect Balance of XC and Trail Performance

The Polygon Siskiu D Series is a well-balanced, versatile option for riders who want the best of both worlds—cross-country efficiency and trail capability. With its 120mm of travel, progressive geometry, and durable frame construction, the Siskiu D is ready for any challenge you throw at it, whether you're climbing technical switchbacks or navigating steep descents.

Looking for a down-country bike that can handle long rides and technical terrain? The Siskiu D is a trail machine that delivers on performance, comfort, and value!