2021 polygon siskiu t8
26 Aug 2020

Polygon's very popular Siskiu T has been updated for 2021 with a new frame, fresh geometry, reworked kinematics, and a little less suspension travel

Indonesian bicycle manufacturer, Polygon, is ready to unleash its newest full suspension mountain bike for 2021; the redesigned and reengineered Siskiu T. Sitting smack-bang in the middle between the Siskiu D (Downcountry) and the Siskiu N (Enduro) the Siskiu T (Trail) is the brand’s most versatile do-it-all trail bike. And thanks to a whole suite of improvements to the frame, geometry and suspension design, the 2021 Polygon Siskiu T is about to get a whole lot more versatile.

2021 polygon siskiu t8
With its bedazzling purple paint job, the Polygon Siskiu T8 is all-new for 2021, incorporating a whole bunch of improvements over the old model.

Same Face, New Muscles

You wouldn’t tell just by looking at it, but Polygon has actually gifted the Siskiu T an entirely new frame. The overall shape is very similar, and it’s still built around a single-pivot suspension platform with the seatstays directly driving the rear shock. A one-piece rocker link connects the seatstays to the frame, not only to help control the leverage rate, but also to provide lateral rigidity and decrease side-loading on the shock itself.

The alloy tubing is all-new however, and the geometry has received a hefty update too. There are also a number of key changes that have been brought over from the latest Siskiu D – a bike that we recently reviewed.

2021 polygon siskiu t8
Taking on board recent geometry trends, the Siskiu T increases its reach by 25-30mm on each frame size.

Drink Some Water!

For a start, you can now fit a water bottle inside the front triangle. How splendid! On all frame sizes, a 600ml water bottle will now sit inside a side-entry cage just underneath the rear shock.

Despite squeezing a bottle in there, Polygon has actually lowered the top tube to improve standover clearance. The seat tube has also gotten shorter, which allows for a longer travel dropper post to be fitted. The S/M sizes come with a 150mm popper, and the L/XL sizes come with a 170mm whopper.

In addition to the longer reach and slacker head tube angle, the Siskiu T also gets a shorter seat tube to accommodate a 150-170mm travel dropper post. And while the chainstays have gotten shorter, there’s still clearance for chubby 2.6in tyres.

2021 polygon siskiu t8
Polygon has moved the shock up the downtube slightly, which has gifted the designers room to fit a 600ml water bottle just below it.

Fresh Geo & Wheelsize Options

Taking on board recent geometry trends, the Polygon Siskiu T gets a 1° slacker head tube angle, while reach measurements have grown by 25-30mm on each size – helping to push the front wheel out further for greater stability. To keep the whole wheelbase from getting too long though, the chainstays have shortened by 5mm. And finally, the seat tube angle has also steepened.

Polygon still produces the Siskiu T in two wheelsizes, and it’s a size-specific dealio. The 27.5in Siskiu T frame is available in Small and Medium sizes, while the 29in Siskiu T comes in Medium, Large and X-Large. That means for the lucky Goldilocks folk out there who fit a Medium, you’ve got both options at your disposal. For everyone else, the decision is a lot easier.

It Actually Has Less Travel

In a departure from every other new bike launch from the past year, the new Siskiu T actually has less rear suspension travel than the old model. Not by much, but we’re still happy that Polygon hasn’t succumbed to ballooning its trail bike into an enduro bike. As before, travel is also slightly different between the two wheelsize options;

  • Siskiu T (27.5in): 150mm front & 140mm rear
  • Siskiu T (29in): 140mm front & 135mm rear

Anti-squat has gone up by 10%, while overall progression in the leverage curve has been reduced ever-so-slightly.

Suspension kinematics have been tweaked, partially due to the rear shock having moved its mounting location a little further up the downtube. It’s also due to the main pivot having moved up too, which purportedly increases anti-squat by 10% over the old bike to improve pedalling efficiency.

To keep things smooth and compliant though, Polygon has moved to a lighter damper tune for the rear shock, and the overall leverage curve has been smoothed out, again to improve sensitivity. There’s also a touch less progression, giving riders more flexibility to tune the spring curve with volume spacers inside the rear shock.

2021 polygon siskiu t8
Each frame size comes with 780mm wide hangers and a 35mm long stem.

Siskiu Two Ways

Polygon will be launching the Siskiu T with two models: the Siskiu T7 and the Siskiu T8. As we’ve come to expect from Polygon and the fact that it’s sold direct-to-consumer in Australia via Bicycles Online, the pricing is very sharp indeed.

Each Siskiu T is built around exactly the same alloy frame, which features a threaded bottom bracket shell, ISCG 05 chainguide tabs, Boost hub spacing and a practical mixture of internal and external cable routing. They’ll come fitted with big 780mm wide riserbars, a stubby 35mm long stem and a TranzX dropper post. You’ll also find chunky 2.6in tyres that are wrapped around Entity rims with a broad 35mm internal width.

The main differences between the two bikes includes the suspension package (Fox vs RockShox), the drivetrain (Shimano SLX vs Deore) and the brakes (4/4-piston vs 4/2-piston callipers). Here’s a closer look at the spec and pricing for both bikes;

2021 polygon siskiu t8
The Siskiu T8 gets a Fox 34 Rhythm fork, a Shimano SLX 1×12 drivetrain, and Schwalbe Hans Dampf tyres.

2021 Polygon Siskiu T8

  • Frame | ALX Alloy, Single-Pivot Suspension Design, Travel: 140mm (27.5in) – 135mm (29in)
  • Fork | Fox 34 Rhythm, GRIP Damper, Travel: 150mm (27.5in) – 140mm (29in)
  • Shock | Fox Float DPS, Performance Series, 210x55mm
  • Wheels | Entity XL2, Alloy Rims, 35mm Inner Width, Tubeless Compatible
  • Tyres | Schwalbe Hans Dampf ADDIX SpeedGrip, 2.6in Wide
  • Drivetrain | Shimano SLX 1×12 w/MT510 32T Crankset & 10-51T Cassette
  • Brakes | Tektro HD-M745 4-Piston w/180mm Rotors
  • Bar | Entity Xpert Alloy, 35mm Diameter, 20mm Rise, 780mm Wide
  • Stem | Entity Xpert Alloy, 35mm Length
  • Seatpost | Tranz-X Dropper, 30.9mm Diameter, Travel: 150mm (S-M), 170mm (L-XL)
  • Available Sizes | Small & Medium (27.5in), Medium, Large & Extra-Large (29in)
  • RRP | $3,399 AUD
2021 polygon siskiu t7
Using the same frame, wheels and finishing kit as the Siskiu T8, the Siskiu T7 lower the price by spec’ing a Shimano Deore 1×12 drivetrain and a RockShox Recon fork and Deluxe shock.

2021 Polygon Siskiu T7

  • Frame | ALX Alloy, Single-Pivot Suspension Design, Travel: 140mm (27.5in) – 135mm (29in)
  • Fork | RockShox Recon RL, Travel: 150mm (27.5in) – 140mm (29in)
  • Shock | RockShox Deluxe Select+, 210x55mm
  • Wheels | Entity XL2, Alloy Rims, 35mm Inner Width, Tubeless Compatible
  • Tyres | Schwalbe Hans Dampf ADDIX SpeedGrip, 2.6in Wide
  • Drivetrain | Shimano Deore 1×12 w/MT510 32T Crankset & 10-51T Cassette
  • Brakes | Tektro HD-M735 4-Piston Front & 2-Piston Rear w/180mm Rotors
  • Bar | Entity Xpert Alloy, 35mm Diameter, 20mm Rise, 780mm Wide
  • Stem | Entity Xpert Alloy, 35mm Length
  • Seatpost | Tranz-X Dropper, 30.9mm Diameter, Travel: 150mm (S-M), 170mm (L-XL)
  • Available Sizes | Small & Medium (27.5in), Medium, Large & Extra-Large (29in)
  • RRP | $2,699 AUD
2021 polygon siskiu t8
The alloy seatstays drive the 55mm stroke shock via a one-piece alloy rocker link, which aims to reduce side-loading on the shock itself.
2021 polygon siskiu t8
The Siskiu T gets 148x12mm bolt-up dropouts and a slick Shimano 12-speed drivetrain.

Siskiu T8 On Test

To see how all the changes pan out on the trail, we’ll be getting the new Polygon Siskiu T8 in for a proper thrashing on our local test trails. Make sure you stay tuned for an in-depth review on this value-packed trail bike coming in the near future. In the meantime, don’t hesitate to leave us any questions you might have on the Siskiu T and we’ll do our best to answer them for you.

Need more visuals to paint a better picture? Check out Polygon’s promo video for the Siskiu T down below, along with our recent video review of the shorter travel Siskiu D6;


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