Polygon Siskiu D6 first ride review

A burly budget full-susser with XC aspirations

GBP £850.00 RRP
Polygon's full-suspension Siskiu D6
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Full-sus bikes with budget hardtail price-tags tend to raise the odd cynical eyebrow when they arrive at our offices. However, bikes such as Voodoo’s excellent value-for-money Canzo prove that cheap can still mean seriously cheerful, even when it comes to bikes with full bounce capabilities. So what about the Polygon Siskiu D6?


Polygon Siskiu D6 spec overview

  • Frame: ALX Alloy
  • Fork: SR Suntour XCM HLO, 120mm travel
  • Rear suspension: SR Suntour Raidon-Lo, 7.5”X1.9”(190X50MM), M8X22MM
  • Front derailleur: Shimano Alivio FD-M4000
  • Rear derailleur: Shimano Alivio RD-M4000SGS
  • Brakes: Shimano BR-M355
  • Bottom bracket: Shimano BB-ES300
  • Cassette: Shimano CS-HG200, 11-34T
  • Wheelset: Araya DM-650 rims with Shimano hub
  • Tires: Schwalbe Smart Sam, 27.5”X2.25”
  • Saddle: Entity Flux
  • Seatpost: Entity Xpert, 30.9X350MM
  • Stem: Entity Xpert, 80MM
  • Handlebar: Entity Xpert, 740MM

Polygon Siskiu D6 frame and equipment

The D6 is the cheapest in a range of three 27.5in Siskius from Indonesian bike stable, Polygon, and according to its website it’s an ‘XC sport’ machine. Any would-be cross country credentials take a serious hit as you wince during the time honoured test of picking it up to gauge the weight. Tipping the scales at 15.5kg, a spritely race whippet the D6 definitely is not, and despite a relatively climb-friendly seat tube angle of 73.5 degrees, you feel every gram of that heft as you haul the bike uphill.

Once coming down the other side on steep, smooth and flowing trails, with a good-sized reach of 443mm (size large) and slack-ish 68-degree head angle, the D6 is fun to pilot. But while the 740mm bar provides decent levels of control, the long 80mm stem hampers rapid, responsive steering and it doesn’t take much in the way of the rough stuff to get the suspect Suntour suspension combo of 120mm coil sprung XCM HLO fork and Raidon shock massively out of their depth.

Polygon Siskiu D6 ride impression

While the fork copes with unthreatening chatter, thrash it over rocks or roots and it will hammer through its travel and flex horribly on its QR axle as you clatter along. The shock fares slightly better, but is incredibly linear and also quickly devours its travel. There’s no rebound adjustment on either fork or shock, and the fork seems to lack a top bumper as it clanks at the height of its travel.

Chuck cheap Schwalbe Smart Sam tyres into the mix, which easily break loose even in bone-dry conditions, and the ride is scarily unpredictable on anything but sanitised trails.


Polygon Siskiu D6 early verdict

Well-proportioned, but massively enfeebled by weedy suspension and tank-like weight.

Product Specifications


Name Siskiu D6
Brand Polygon

Head Angle 68
Seat Angle 73.5