2021 Polygon

SISKIU D5

A 27.5″ aluminum frame full suspension trail bike with mid-range components.
Compare the full range

MSRP$1,249
Weight37.5 lbs  
FrameAluminum
SuspensionFull, 120 / 100mm
ForkSuntour XCM
ShockSuntour
Wheels27.5″ Aluminum
Drivetrain1 × 9
GroupsetAlivio, Altus
BrakesHydraulic Disc
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Insights
Ride Feel

Based on frame geometry and build specs.

Terrain
easyextreme
Handling
nimblestable
SISKIU D5
Other Trail bikes
Gearing

A bike with lower gearing will be easier to ride up steep hills, while a higher top end means it will pedal faster down hills.

Lowest gear

(climbing)

27 mph

SISKIU D5

26 mph

Similar Bikes

Highest gear

(descending)

Spec Level

Based on build material and quality level of the frame, fork, wheelset, groupset, suspension system, and more.

Compare the full Siskiu model range

View Comparison
Sizing
SM

5'0" – 5'5"

MD

5'3" – 5'9"

LG

5'7" – 6'1"

Rider Fit Notes

None yet.

Do you have this bike? Help other riders make a decision about which size will work for them by sharing your own size and fit notes.

Reviews
Beta
The Beta Tests: Polygon Siskiu T8

Dec 2021 · Ryan Palmer

Possibly the best $2,500 bike we've ever ridden.

Highs
  • Fully capable, modern trail bike geometry

  • Excellent parts spec for the price

  • Internal cable routing

Lows
  • Resin-only brake rotors create weak braking

  • Suspension platform isn't very sophisticated

Read Review

Two Wheeling Tots
Polygon Siskiu D24 Full Suspension Kids Mountain Bike

Oct 2021 · Kelly Jorgensen

An affordable full suspension 24" kids mountain bike? The Polygon Siskiu D24 is a perfect blend of price and performance. Read the review!

Read Review

Outdoor Gear Lab
Polygon Siskiu D7

Oct 2021 · Jeremy Benson

As the price of bikes continue to skyrocket, Polygon bucks that trend with their direct-to-consumer sales model and the affordable Siskiu D7. This...

Highs
  • Reasonable price

  • Comes with a dropper post

  • Fun on a range of terrain

  • Efficient climber

  • Playful on descents

Lows
  • Non-boost fork

  • Some cable rattle over rough terrain

  • Can be overwhelmed on aggressive trails

Read Review

Flow Mountain Bike
Polygon Siskiu T8 Review | Big fun without the big price tag

Jan 2021

Polygon's updated Siskiu T is proof that you don't have to spend the earth to get a very capable trail bike. Featuring on-trend geometry, a robust build kit and a host of improvements over the old model, the Siskiu T8 will have you questioning why you'd need to spend any more.

Highs
  • Exceptionally capable package for the money

  • Confidence-inspiring geometry

  • Grippy high-volume rubber

  • Supple & supportive suspension

  • Sporty handling for a tough trail bike

Lows
  • Handlebars need more sweep

  • Brakes aren't hugely powerful

  • The wheels ain't light

Read Review

Bikerumor
New Polygon Siskiu T gets the right updates for seriously competitive & affordable trail bike

Aug 2020

Looking for a full suspension mountain bike you can actually afford? The Polygon Siskiu T just got overhauled, and it looks good.

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Loam Wolf
Budget Bike Shootout: Polygon Siskiu T7 LTD

Jun 2020

The Polygon Siskiu T7 LTD is a solid, affordable mountain bike and one that will certainly make a lot of rider’s dreams come true. Aggressive riders looking for a great budget bike should read our detailed review of the Polygon Siskiu T7 here!

Read Review

NSMB
Polygon Siskiu N9 160mm 29'er Review

Feb 2020

Polygon's 160mm aluminum 29'er looks to deliver value and performance and shows potential for 2800 USD...

Read Review

Pinkbike
Review: Polygon Siskiu T8

Sep 2018 · Richard Cunningham

Add this well-outfitted and sharp-handling 29er to your short list of affordable trail bikes.

Highs
  • Lively acceleration and climbing

  • Precise handling and cornering

  • Excellent value

Lows
  • No room for a water bottle

  • Not plush in rough terrain

  • No size small with 29-inch wheels

Read Review

Geometry
99 Spokes on YouTube99 Spokes on YouTube
Specs
Build
Frame

ALX XC 120MM TRAVEL (27.5”) TAPER H/T QR BOOST

ColorGrey / Maroon

Fork

SR SUNTOUR XCM HLO, QR 100MM, 120MM (27.5”) TRAVEL

Travel100mm

Spring TypeCoil

Shock

SR SUNTOUR RAIDON LO AIR E2E:190X51MM HARDWARE:M8X22MM

Travel120mm

Spring TypeCoil

Bottom Bracket

INCLUDE CRANKSET

Headset

ZS 44/28.6 | ZS 56/40

Stem

ENTITY SPORT, ALLOY

Handlebar

ENTITY SPORT, ALLOY

Saddle

ENTITY VOID SADDLE

Seatpost

ENTITY SPORT, ALLOY

TypeRigid

Pedals

-

Groupset
Rear Derailleur

SHIMANO RD-M3100

Crank

SHIMANO ALTUS FC-MT2102 36T

Shifters

SHIMANO SL-M3100, 2x9 SPEED TRIGGER

Cassette

SHIMANO CS-HG200 11-36T

Chain

KMC X9

Chain Guide

none

Brakes

SHIMANO HYDRAULIC DISC BRAKE

TypeHydraulic Disc

Brake Levers

SHIMANO BL-M201 HYDRAULIC DISC BRAKE

Wheels
Rims

ALLOY DOUBLE WALL 32H

Tires

SPIDERBAIT TIRE 27.5"x2.25"

Rider Notes
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Last updated February 12
Not listed for 406 days