2021 Polygon Siskiu D5 Review and First Impressions

I have been thinking about buying a new full suspension mountain bike for a while. The problem is that due to well documented supply chain issues, new bikes are in short supply all over. However, Bikes Online has a fairly well stocked inventory. After a lot of research I bought a 2021 Polygon Siskiu D5 from them for $1,099.00 US.

The Siskiu D5 is an aluminum framed bike, with a rear air shock and a front spring fork with lockout, both by SR Suntour. The bike has 27.5 inch wheels and tires, both by Polygon's house brand Entity. Brakes are Shimano M201s hydraulic units. All other components are Entity.

I managed one ride before a Nor'easter closed all my local trails for the winter, except for fat tire bikes. That said, in that one ride it became apparent that the Siskiu D5 is a well built and decently spec'd bike. It is stable and responsive, and frankly, all kinds of fun to ride. I definitely give this bike two big thumbs up! Specifications are below.

Specifications

Cost: $1,099.00 US with free shipping to lower 48.

Frame: ALX XC 120mm travel (27.5”) Taper H/T QR boost
Fork: SR Suntour XCM HLO, QR 100mm, 120mm travel
Rear Shock: SR Suntour Raidon LO Air E2E:190X51mm
Handlebar: Entity Sport, alloy W:760mm R:12mm BB:31.8mm
Stem: Entity Sport, alloy E:45mm R:-DEG BB:31.8mm
Headset: ZS 44/28.6 | ZS 56/40
Saddle: Entity Void, steel rail
Seatpost: Entity Sport, 0mm offset, 30.9mmX350mm
Crankset: Shimano Altus FC-MT2102 boost 9SP 36X22T 170mm
Pedals PP flat pedal
Bottom Bracket: BSA threaded
Chain Guide: NA
Chain: KMC X9 9 speed
Cassette Sprocket: Shimano CS-HG200 9-speed 11-36T
Front Derailleur Shimano Alivio FD-M3120-E
Rear Derailleur: Shimano Alivio RD-M3100 9-speed
Shifting Lever: Shimano Alivio SL-M3100 9-speed
Brake Lever: Shimano BL-M201 hydraulic disc brake
Front Brake: Shimano BR-M201 hydraulic disc brake
Rear Brake: Shimano BR-M201 hydraulic disc brake
Rotor: Shimano SM-RT10 F:180mm / R:160mm
Tire: Entity Spiderbait 27.5”X2.25
Wheelset: alloy double wall rims (27.5”) w/alloy hubs

Geometry (Medium)

Seat Tube Length 17"
Seat Tube Angle 435mm
Effective Seat Tube Angle 70mm
Head Tube Length 75.5mm
Head Tube Angle 105mm
Effective Top Tube 67mm
BB Height 595.1mm
BB Offset 326mm
Chainstay 27mm drop
Wheelbase 432mm
Frame Reach 445mm
Frame Stack 696mm
Standover Height 580.4mm