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Today’s DealsSISKIU D6
A 27.5″ / 29″ aluminum frame full suspension trail bike with upper mid-range components.
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Manufacturer Price
$1,149| Weight | 37.6 lbs |
|---|---|
| Frame | Aluminum |
| Suspension | Full, 120 / 120mm |
| Fork | Suntour XCM |
| Shock | Suntour |
| Wheels | 27.5″ / 29″ Aluminum |
| Drivetrain | 1 × 10 |
| Groupset | Deore |
| Brakes | Shimano Hydraulic Disc |
| Seatpost | Dropper |
4'11" – 5'5"
5'3" – 5'9"
5'7" – 6'1"
5'11" – 6'5"
Summary
The Polygon Siskiu is a versatile enduro bike that excels in downhill performance, offering a smooth and confidence-inspiring ride with its Fox suspension. It's praised for its impressive value, modern geometry, and quality components, though some reviews note it's less efficient on climbs and flatter trails. The bike's competitive price and upgrade potential are frequently highlighted.
Smooth and confidence-inspiring Fox suspension
Impressive value for money
Modern geometry and quality components
Competitive price with upgrade potential
Versatile downhill performance
Less efficient on climbs and flatter trails
Heavy wheels and tyres slow acceleration
Rear shock lacks mid-stroke support
Noisy chain and rattling on descents
Budget all-rounder with formidable spec list
The Polygon Siskiu is one of the best cheap mountain bikes out there.
The 2021 Siskiu T8 is easily one of the best bikes we've ridden in this price range.
without a motor getting in the way, the design looks a bit more refined on this enduro bike than on the BromoPinkbike
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Oct 2023 · Mick Kirkman
The Siskiu T8 offers an impressive spec and is deceptively capable downhill. It’s not the best all-rounder, though, and won’t cover flatter ground as quickly as some
Suspension delivers a calm and secure ride feel
Impressive-value components
Drivetrain and fork/shock combo are sorted for the cash
Feels more of an enduro than trail bike when it comes to hammering uphill or snaking along flatter singletrack

Feb 2023
The Polygon Siskiu T8 is a 135mm, 29er that outshines it's $2,600 price tag and was a tester favorite during our recent Budget Bike Round Up.
Capability
4 piston brakes
Price point
Tektro Brake Levers
Requires precise shock settings

Jan 2023 · Alan Muldoon
The Polygon Siskiu is a hard hitting 29er trail bike with 135mm of travel and a 140mm fork. Dig a little deeper however, and you quickly discover that this isn’t your typical entry-level full suspension bike that’s been dumbed down for mass production. In fact, it’s one of the best budget mountain bikes out there. Best mountain bikes: the ultimate trail, enduro and XC bikes Need to know: Fox 34 fork and Float DPS shock deliver 140mm and 135mm of travel respectively Polygon offers four frame size with a generous 496mm reach on the XL Shimano SLX 12 speed derailleur, shifter and cassette, but with a KMC chain The in-house Entity components are all top quality. The Siskiu gets a relatively slack 65.8º head angle for a stable steering response, ultra-short 430mm chainstays to make it easier to loft the front end, and generous reach measurements across the four frame sizes to guarantee a good fit. And while lots of brands make a big song and dance about custom sizing, but fail to provide short enough seat tubes with adequate dropper post insertion to make it possible to upsize, Polygon has nailed it on the Siskiu T8. With the 430mm seat tube we could comfortably ride the XL bike with the 170mm dropper with room to upgrade to a 200mm post if needed. Detailing on the Siskiu frame is also first rate, from the copper highlights under the seat collar that matches the logo on the underside of the downtube, to the one-piece rocker link that adds frame stiffness while maintaining a minimalist, clean look. Even the bespoke chainstay protection looks fitting for a more expensive bike. Cable routing on the Siskiu is internal on the front triangle, and thanks to tighter sealing on the entry and exit ports for the cables, there was no noticeable rattle. That’s not to say the Siskiu was a silent runner, however. The large loop of brake hose that’s necessary to prevent it from kinking as it exits the rear brake calliper has a tendency to touch the spokes of the rear wheel after the suspension has been compressed, so it can sound like you have a stick stuck in the swingarm. Suspension Getting Fox suspension on a £2k trail bike is quite a boon. And while the 140mm travel Fox 34 Rhythm fork isn’t quite as stout as the 35mm chassis on the RockShox equipped Jamis Faultline, an equivalently-priced bike, it’s only 1mm smaller, so nothing to write home about. The Fox 34 feels responsive and supple off the top, and with a good degree of ramp up it doesn’t bottom too easily on bigger hits. We measured the rear travel on the Siskiu frame at 136mm, so clearly there’s no rounding up here. The single pivot suspension design is controlled by an inline Fox Float DPS shock. It offers a really usable range of rebound adjustment that will comfortably cover a wide variety of rider weights. Using all of the travel doesn’t …Continue reading »
Progressive sizing and geometry, great value for money
Needs a Shimano chain

Sep 2022 · Jeremy Benson
The Polygon Siskiu T8 is an excellent mid-travel trail bike offered at a reasonable price. Polygon's consumer-direct sales model helps keep it affordable...
Awesome build for the price
Versatile
Well-rounded performance
Firm grips
Saddle shape

Apr 2022 · James Smurthwaite
Polygon's race team has been spotted at Sea Otter on a new enduro bike that is due to replace the current Siskiu N9..
Dec 2021 · Ryan Palmer
Possibly the best $2,500 bike we've ever ridden.
Fully capable, modern trail bike geometry
Excellent parts spec for the price
Internal cable routing
Resin-only brake rotors create weak braking
Suspension platform isn't very sophisticated

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!

Aug 2020 · Zach Overholt
Looking for a full suspension mountain bike you can actually afford? The Polygon Siskiu T just got overhauled, and it looks good.
Dec 2023 · Relaxed Stingray
If you are looking for an excellent entry into mountain biking look no further. It's a very capable bike with a pretty average front suspension, whic
Cool looking. Value entry level into mountain biking with a capable bike.
Front suspension very average.
| Frame | aluminum BB Standard: BSA, 68mm, Threaded Color: Web Orange |
|---|---|
| Fork | SUNTOUR XCM BOOST 120mm TRAVEL Travel: 120mm Spring Type: Coil |
| Shock | SUNTOUR RAIDON LO AIR, E2E: METRIC 190x45mm Travel: 120mm |
| Bottom Bracket | BSA THREADED 68/73mm |
| Headset | THREADLESS ZERO STACK HEADSET, ZS 44/28.6 | ZS 56/30 |
| Stem | ENTITY SPORT ALLOY, EXT: 45mm, BB: 31.8mm, R/D: 0Degree |
| Handlebar | ENTITY SPORT ALLOY, W: 760mm, BB: 31.8mm, R/D: 12mm, B: 6degree |
| Saddle | ENTITY VOID SADDLE, ø 7mm |
| Seatpost | RAGE-I DROPPER 150mm / 170mm travel, 30.9 x 442mm (S-M) / 495mm (L-XL) Type: Dropper |
| Pedals | PP PEDAL |
| Rear Derailleur | SHIMANO DEORE RD-M4120 DIRECT ATTACH 10-SPEED |
|---|---|
| Crank | SHIMANO DEORE FC-M5100-1 32T TWO-PIECE-CRANK |
| Shifters | SHIMANO DEORE SL-M4100, 10-SPEED TRIGGER |
| Cassette | SHIMANO DEORE CS-M4100 10-42T 10-SPEED |
| Chain | KMC X10-1 |
| Brakes | SHIMANO MT201 HYDRAULIC DISC BRAKE Type: Shimano Hydraulic Disc |
| Brake Levers | SHIMANO MT201 HYDRAULIC DISC BRAKE |
| Rims | ALLOY DOUBLE WALL 584 / 622-24 32H FOR TYRE 584 / 622-35/68 |
|---|---|
| Spokes | Entity Stainless, Brass Nipple |
| Front Hub | SHIMANO HB-MT400-B THRU AXLE 15x110mm 32H CENTER LOCK |
| Rear Hub | SHIMANO FH-MT400-B THRU AXLE 12X148mm 32H CENTER LOCK |
| Tires | DELI 27.5"x2.25" / 29"x2.25" |
| Disc Rotors | SHIMANO SM-RT10 F:180mm R:160mm CENTER-LOCK |
First added November 19
Last updated April 29
Not listed for 1,129 days