Polygon Siskiu T8 Dual Suspension Mountain Bike

WAS $2,999.00 You Save $300.00

Shipping Calculator


Key Features

  • AL6 Alloy Boost Trail frame with 150mm (27.5") / 140mm (29") of suspension travel (internal routed)
  • Tapered Head Tube
  • Rockshox Revelation RC front air fork
  • Rockshox Deluxe RT3 air shock with external rebound and 3 position compression
  • 1 x 11 Shimano Deore XT / SLX drivetrain
  • Tranz-X 150mm Dropper seat post
  • Entity XL2 tubeless ready wheelset with Schwalbe Nobby Nic tyres.
  • 5 Year Warranty on frame
  • Full manufacturer’s warranty on parts
  • Weight: 13.8kg
For the past 18 months we have received a significant amount of requests from our customers looking for a top spec, bigger travel, trail ready whip that could be delivered at one of the sharpest prices in the market. In response, Polygon have released their top of the line alloy, dual suspension trail mountain bike - the Siskiu T8. The T8 takes a step up in performance from the T7 with a combination of parts and technology designed for bigger hits, faster riding, and more nimble handling.
The Siskiu T is built around a new lightweight, hydroformed 6061 aluminium Boost frame and longer 140mm (29er) / 150mm (27.5") travel. By utilising a one piece linkage system, Polygon have been able to keep the frame weight down whilst reinforcing high-stress areas and reducing flex under heavy loads. The rear swing triangle also features a unibody pivot bridge that stiffens the rear wheel and provides you a lot more control when exiting high-speed corners and negotiating rock gardens. The Boost design means that Polygon have been able to include wide 29mm rims with 2.6" tyres (27.5" wheel) and 2.35" tyres (29" wheel). The frame is finished off with a tapered headset, rear thru axle, and internal routing for gears, brakes and 150mm dropper post.
The  Siskiu  T series utilises  Polygon's new Wheel Fit Size System whereby each frame size is paired with the wheel size that best fits the rider and sets them up for optimal efficiency and power transfer. We pair 29er wheels with 18.5" and larger bikes, and more proportional, better-fitting  27.5-inch  wheels for 17.5" and smaller bikes.
An upgraded Shimano 1 x 11 drivetrain powers the T8 with an 8000 series Shimano XT rear derailleur with a clutch and a massive 46T rear cassette providing plenty of range to glide up those steep climbs. The Prowheel crankset is a 2 piece unit and comes with a chain retention (narrow-wide) chainring, eliminating the need for a bulky chain guide and continuing the clean looks of the bike.
Dampening duties on the T8 are provided by a Rockshox Revelation RC front air fork which now comes with a new 35mm stiff and lightweight chassis derived from the iconic Rockshox Pike. This is combined with a dependable Rockshox Deluxe RT3 air shock on the rear with external rebound and 3 position compression. The bike rolls on a pair of wide 29mm rim Entity XL2 tubeless ready wheels and Schwalbe Nobby Nic tyres with a nice and wide 2.35" to 2.6" width giving you loads of traction for climbs and hitting the berms.
Completing the Polygon Siskiu T8 is a Tranz-X 150mm dropper seat, Entity Xpert cockpit, and Shimano MT500 Hydraulic Disc Brakes. 



Check out the links below for a review of the 2018 Polygon Siskiu T8:

Tested: Siskiu T8 - Flow

Bike Test: Polygon Siskiu T8 - MountainBiking Australia

Product Review Polygon Siskiu T8

Model Comparison Chart


Siskiu T7

Siskiu T8


AL6 Alloy Boost Trail frame with 150mm (27.5") / 140mm (29") of suspension travel (internal routed), Tapered headtube

AL6 Alloy Boost Trail frame with 150mm (27.5") / 140mm (29") of suspension travel (internal routed), Tapered headtube


Rockshox Recon RL Solo Air Boost fork, Travel 150mm (27.5") / 140mm (29") External rebound, low speed compression15mm  thru  axle

Rockshox Revelation RC Debon Air Boost fork, Travel 150mm (27.5") / 140mm (29"), External rebound, low speed compression, 15mm thru axle (new 35mm stiff and lightweight chassis derived from Pike)


X-Fusion O2 Pro rear air shock with 2 position compression rebound adjustment

Rockshox Deluxe RT3 air shock with external rebound and 3 position compression

Drivetrain Shimano XT / Deore Shimano Deore XT /  SLX
Speed 1 X 10 Speed 1 X 11 Speed
Brakes Shimano M365 Hydraulic Disc Brakes Shimano Deore BR-MT500 Hydraulic Disc Brakes
Wheelset Entity XL2 Disc 29-584 (27.5”) / 29-622 (29”), tubeless ready Entity XL2 Disc 29-584 (27.5”) / 29-622 (29”), tubeless ready
Weight 14.2kg 13.7kg
Price $2,299 $2,999

Tranz-X 150mm Dropper seat post

Tranz-X 150mm Dropper seat post



2018 Polygon Siskiu T8 (27.5 inch or 29er)

2018 Giant Trance 2 (27.5 inch)



AL6 Alloy Boost Trail frame 150mm travel (27.5”) / 140mm travel (29”),
Tapered headtube

Alloy Maestro frame 140mm travel



Rockshox Revelation RC Solo Air Boost
Travel 150mm (27.5") 140mm (29"), Tapered Steerer,
15mm thru Axle 

Fox 34 Rythm Boost

Polygon better


Rockshox Deluxe RT3 Air shock

Fox Float Performance

Polygon better


Entity Xpert, Alloy, 780mm

Giant Connect Trail 31.8 Alloy



Entity Xpert, Alloy 45mm

Giant Connect Alloy



Entity Assault Saddle

Giant Contact 



Tranz-X Dropper Post 150MM Travel, zero offset, 30.9MM

Giant Contact Switch, Dropper post, 30.9mm



Prowheel Charm-32T-TT-B 32T Boost 2-Piece-Crank

Praxis SLX, 30T

Giant better


VP Alloy

None included

Polygon better


BSA Threaded


Polygon better


Sunrace CSMX8 11-Speed 11-46T

Shimano SLX 11-Speed 11-46T

Giant better






Shimano Deore XT RD-M8000 with clutch

Shimano SLX M7000

Polygon better


Shimano SLX SL-M7000

Shimano SLX M-7000



Shimano BR-MT500 Hydraulic,
Rotor 180mm front, 160mm rear

Shimano SLX Hydraulic

Giant better


Schwalbe Nobby Nic, 27.5”X2.60” / 29”X2.35”

Maxxis High Roller II 27.5"x2.4"

Similar (Polygon wider)


Entity XL2 Disc 29-584 (27.5”) / 29-622 (29”), tubeless ready

Giant XC-1 disc 27.5, tubeless

Similar (Polygon wider)


Stainless Steel Spokes




Entity, sealed bearings

Giant Tracker, sealed bearings



Yes (some regional and  remote postcodes excluded)


Polygon better



$3,699 (Source: Giant Website AUS
Oct 17)

$700 Difference

Size Chart




RIDER HEIGHT 155-170cm 170-180cm 180-190cm 190-200cm
SEAT TUBE LENGTH 15.5" 17.5" 18.5" 20"
WHEEL SIZE 27.5" 27.5" & 29" 29" 29"


Note: If you are in between sizes, measure your wingspan. If it is greater than your height, go for the frame size up. If your height is greater than your wingspan, go for a frame size down.



  A B C D E F G H I J K L M
Model Size Seat Tube Length Seat Tube Angle Effective Seat Tube Angle Head Tube Length Head Tube Angle Effective Top Tube BB Height BB Offset Chainstay Length Wheelbase Frame Reach Frame Stack Standover Height
SISKIU T Small (27.5") 395 68.5 74.9 105 66 571 336.5 20 430 1145.9 410 595.1 663.3
  Medium (27.5") 435 68.5 74.5 110 66 596.3 336.5 20 430 1168 430 599.7 695.1
  Medium (29") 435 68.5 74.5 100 66.5 601.5 337 39 435 1170.8 430 618.4 697.9
  Large (29") 485 68.5 74.1 105 66.5 627.4 337 39 435 1192.8 450 623 734.3
  Extra Large (29") 520 68.5 73.9 110 66.5 656.7 337 39 435 1219.8 475 627.6 758.7

We understand how important shipping is once you click "buy now", that's why we have the following policies

Australian Warehouse

All products are in stock and ready to ship from our Sydney warehouse (with the exception of preordered bikes, which have the dispatch date illustrated)

Next day dispatch

All orders received by 5 pm AEST will usually be dispatched the following business day. If an order is placed on the weekend or public holiday, please note dispatch will usually be the next working day. For tracked shipments, please allow 12 hours for tracking to begin.

Shipping of Parts, Accessories and Apparel

Economy Shipping

There is free delivery available on all small parcels Australia wide using tracked services of Australia Post or Fastway, no minimum order value required! Estimated delivery time is 4-9 business days. 

Express Shipping

We do also offer Express Shipping for a small additional fee on parts, accessories and apparel orders. Estimated delivery time on Express Shipping is 1 to 4 business days.

Shipping of Bikes

Shipping of bikes and other bulky goods is free to 85% of residences in Australia. However, some postcodes incur a surcharge starting from $29. 

Once shipped you will be issued a consignment number which can be used to track your parcel. We use Direct Freight Express for deliveries and you can track your delivery by calling 1300 347 397 or online at www.directfreight.com.au


We’re so confident that you’ll love our extensive range of bikes, that we’ll let you ride one as your own for a full 14 days and if you don’t like it, simply e-mail us at sales@bicyclesonline.com.au and we’ll pick it up from you, free of charge! Just make sure you keep the box so it can be re-used to send it back. Click here for more information. 

All of our bicycles come with a Free Pro Build valued at $99. This means that your bicycle will be pre built by our professional mechanics. For your convenience, safety and comfort all our bikes are fully assembled prior to delivery. The bike is then packaged back into a box for secure shipment.


When your bike arrives, all you have to attach is the front wheel, the handlebar and pedals, everything else has been done – the headset has been adjusted, wheels trued, pedals and seat post greased, brakes and gears calibrated, and the tyres have been pumped up (please note upon arrival, in some cases you may need to add more air to tyres).

Most companies simply sell you the bike as it comes from the factory, which will require significant know-how to get your bike on the road. Currently we are the only Australian company providing this service, and have the 14 day test ride to back it up.

All the tools required to assemble the bike are included. 

Please note, that all bicycles whether purchased online or instore, are mechanical devices and need to be serviced regularly to ensure proper functioning. New gear and brake cables, will stretch during the initial bed-in period, and will need to be adjusted after approximately 150-300km. 

Whilst your new bicycle will have already gone through our Pro Build process, you will still need to complete some minor final assembly steps when you take your bicycle out of its box.

Please follow the video playlist below to correctly complete the setup of your new bike:


Assembly Time:

  • 10-15min - You have assembled bikes before
  • 15-25min - You are mechanically handy
  • 30-40min - Never assembled a bike and working with tools isn't your thing


Unboxing your bike:

Start by carefully opening the top flap to expose the contents. You will see the bike with plenty of protective packaging and next to the rear wheel, the saddle & seatpost, a small cardboard box where your pedals, tools, bell and reflectors are. If you ordered any other products with the bike, it is likely they were placed on the bottom of the box as well. Remove all the loose items before pulling the bike out of the box and gently placing it on the floor.

Keep the box and all the protective packaging found on the bike in case you choose to change frame sizes, upgrade/downgrade the bike, or return the bike for a full refund under the 14 Day Test Ride Policy.


How to install a thru axle:


Disc Brake Setup:


How to Install Handlebars and faceplate:


How to install pedals on your bike:


Congratulations on your Purchase:

This bicycle is backed by a 5 year factory warranty on the frame and full manufacturer’s warranty on parts.

Warranty is valid only for bicycle that has been properly and well-maintained under the following conditions:

Warranty includes:

  • All damaged or fractured or broken frame / fork / component which was caused by manufacturing or assembling error in factory.
  • Non functioning mechanism caused by manufacturing error in factory.

Warranty is NOT valid for:

  • Incorrect assembly, i.e pedals installed in the wrong crank arm. 
  • Normal degradation caused by frequent use, such as degrading brake shoe, deflated tire, etc
  • Surface defects, such as stained, marred, defaced, etc
  • Damaged caused by misuse or accident
  • Other damages which are not caused by factory error
  • Bicycles which have been sold to another party
  • Bicycles used in commercial capacity, such as rentals
  • Bicycles which have not been well-maintained

For any damages which is guaranteed by the brand as the first condition above, the brand will repair or replace damaged frame / fork / component with the one of the same brand or similar.

Warranty is valid for all Polygon and Marin bicycles to the original owner only, by showing the purchase invoice.  

To make a claim click here.

Product Reviews