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2021 Polygon Siskiu D7 Review



December 10, 2020

polygon siskiu d7 mountain bike

Polygon Siskiu D7 2021 Review Summary (Quick Stats)

If you don't have time to read the full article, here is our quick review.

Polygon just keeps outdoing themselves with every release. The addition of a dropper on the 2021 Siskiu D7 rounds out this great value for money dual suspension MTB bike. (Available at Check Current Price)

Overall Rating: 
4.3/5 stars




PRICE (at time of writing)


Affordable, flexy, and an efficiently smooth ride for the price.

Heads up! The 2021 Polygon Siskiu D7 is here & it comes with a dropper! Some of the other upgrades include a whole suite of improvements to the frame, geometry, and suspension design.

Polygon mountain bikes are mostly named with a letter and a number. The letters can quickly be broken down into; D = Cross Country riding, T= Trail riding, and N = Enduro riding.

Polygon bikes are increasingly becoming popular mountain bikes in Australia. They are one of the few bike brands that offer a line of affordable, competitively-priced bikes that athletes and general users love for years. And, it’s not only because of the budget-friendliness but also because of the fantastic features and bold designs.

In this new and currently best selling 2021 Polygon Siskiu D7, Polygon capitalized on its extensive R & D, state of the art testing facilities, and feedback from top-level riders (the likes of Tracey Hannah, Daniel Wolfe, and Sam Reynolds).

The outcome? – A bike that defies what an outstanding value dual-suspension mountain bike is capable of. All the recent upgrades tick all the boxes for those looking for a modern-looking bike with great XC pedalling efficiency and all-mountain capability. Also checkout our review of the Siskiu T7.

2021 siskiu d7 side view

Polygon Siskiu D7 Dual Suspension Bike – What’s New?

Build Quality & Geometry.

Polygon D7 is built around a lightweight, ALX alloy XC aluminium frame that boasts a Modern XC Geometry. The bike design also uses internal cable routing for a sleek and clean look.

The structure looks a lot like that of the 2020 Polygon Siskiu D7 model because it was created from the brand’s tube library, a center of previously tested designs & shapes that Polygon knows works.

The new 2021 D7 model utilizes a slack head tube, a lower Bottom Bracket, and a shorter chain-stay to ensure that the bike handles perfectly and travels effortlessly up and down the mountain.

Water Bottle Mount – Stay Hydrated!

Unlike its predecessor, the new D7 model has room for a 600ml water bottle inside the front Triangle. Despite this new addition, the top tube is slightly lower to improve standover clearance. The seat tube has also been shortened to allow for easy fitting of a longer dropper post.

Wheel Size Options

The new Wheel Fit Size System is perhaps one of the most significant upgrades to the Siskiu D7 frame. Each frame size is paired with the wheel size that best fits the rider and sets them up for optimal efficiency and power transfer. For instance, the 29er wheels are matched with 18.5″ and larger bikes, while the 27.5-inch wheels are fitted only to 17.5″ and smaller bikes.

A Dropper Post? Heck Yeah!

Another big standout and an absolute boon for the Siskiu D7 is the dropper post (available in 150mm for S/M or 170mm for L/XL), making the bike exceptionally more capable & comfortable, especially when descending.

Given the bike’s low price, I expected the dropper to be floppy, but it’s not. The post gives you a pretty comfortable riding position – it’s a big confidence booster for this bike.

High-performance Suspension

Once gravity’s working against you, you’ll appreciate a sound suspension system. There is considerably less stiction in both the Front Rockshox Recon RL fork and the rear Rockshox Deluxe Select Plus shock, which means you can easily overcome almost all obstacles in your way. Besides that, the bike also has an optimized anti-squat kinematic with a progressive suspension ratio.

Ride Impressions

If you rode the Siskiu D7 with no prior knowledge, you’d think you’d jumped on an expensive enduro bike. The stable wheelbase and the relatively tall front-end combination make you feel capable of charging into any trail in Australia. This is helped by the rear DebonAir Rockshox Deluxe Select Plus suspension and the Rebound & Compression Adjuster, which is amazingly supple off the top, ironing out most of the trail’s chatter and giving almost unbreakable grip in the turns.

Add in the rollover abilities of the 29-inch wagon wheels, and you’ve got a bike that eats up tremendous obstacles and travels at an incredible speed – almost too much on tighter, less used trails. I found the straight & wide profile of the handlebar a bit of a handful to manoeuvre. It’s virtually sweep-less and resulted in noticeable wrist fatigue on my 3-hour ride through Adelaide Hills trails.

2021 Polygon Siskiu D7 Specs

  • Frame: ALX XC Trail 6061 Aluminum Frame, 120mm Travel, Internal Routed Gear & Dropper Cables, Tapered Headtube, 73mm Threaded Boost BB, 148x12mm Boost Thru-Axle
  • Fork: Rockshox Recon RL, Solo Air, 120mm Travel (27.5″ & 29″), Rebound & Compression Adjuster, 46mm (27.5″) & 51mm (29″) Offset, Maxle Stealth Axle 100x15mm
  • Rear Shock: Rockshox Deluxe Select Plus, DebonAir, Rebound & Compression Adjuster, E2E 190x45mm, M8x25mm Hardware
  • Headset: Threadless Zero Stack Headset, ZS 44/28.6 | ZS 56/40
  • Crankset: Shimano Deore FC-M5100 Boost 32T, Crank Length: 170mm (S, M) / 175mm (L, XL)
  • Drivetrain: Shimano Deore M5100 1X11 Speed Wide-range
  • Bottom Bracket: BSA Threaded 73mm
  • Brakes: Shimano BR-M201 Hydraulic, Rotor F/R: 180/160mm
  • Tire: Schwalbe Nobby Nic Performance 27.5/29×2.25″, Tubeless ready*
  • Rim: Entity X15 Doublewall Disc 32H, 30mm Internal Width, Tubeless Ready*
  • Spokes: Stainless Steel Spokes, *tubeless tape, and valve sold separately
  • Seatpost | Tranz X JD-YSP23JL, 459mm with a dropper post 150mm (S-M) / 170mm (L-XL) Travel, Remote Lever.
  • Wheels | wide 29mm rim Entity X15 double-wall wheels.
  • Wheel Sizes | Small (27.5in), Medium, Large & X-Large (29in)
  • Price:$1,699.

siskiu wheel cassette

Are polygon mountain bikes any good?

Aside from the fact that they are affordable, there’s actually a lot to like about Polygon bikes. They are made with a sturdy frame in modern, well-considered geometry, and as a result, they offer riders plenty of confidence for tackling all terrains. The D7 is perfectly made for seasoned riders and is a fantastic entry point for those getting into the dual suspension crowd. If you’re interested in dirt jumper bike, see out Polygon Trid review.

I certainly recommend checking out their wide range of high-performance bikes, which are well suited to cater to different types of riders’ preferences and requirements. You can find road bikes designed for women, urban and tourism purposes, as well as mountain bikes in a wide variety of build and design, to suit varying applications and terrains.

Is the Polygon D7 Suspension Bike Right For You?

If you are a regular mountain biker and want an on-budget dual-shock bike for the best performance on everything from rough terrains to gnarly descents and marathon races, then this is the bike you are looking for. You know the bike is build to cruise over every trail, so you won’t be worried if the frame material, suspension, or components will hold up whenever you are out adventuring on a new track.

Don’t think the Polygon D7 fits your style? Check out our other reviews of some of the other entry-level options available from Bicycles Online here.

Trek Marlin 5 Review

Roscoe 8 MTB Review

Polygon Cascade 4.0 Mountain Bike Review

Trek 3500 Mountain Bike Review

Trek Marlin 7 Mountain Bike Review

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About the author 

Beastie Bikes Pete

Hi I'm Pete. I'm a passionate mountain biker in Australia. I enjoy writing about biking as much as doing it......almost!

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