Quiver

2026 Polygon Siskiu T T6 UDH vs 2026 Forbidden Reya Tier

The Forbidden Reya Tier size closest to your M is the S2. Compare the S2 instead

What changes on the Forbidden Reya Tier

Compared with the Polygon Siskiu T T6 UDH in M, the Forbidden Reya Tier in S3 places the top of the head tube 16 mm higher and 10 mm further forward, relative to the bottom bracket. Its wheelbase is 30 mm longer, which can contribute to stability at speed.

Frame stack
+16 mm
Higher front end
Frame reach
+10 mm
Longer frame reach
Wheelbase
+30 mm
Longer: steadier at speed
Head angle
+0.5°
Steeper: sharper steering
Chainstays
n/a
One of the bikes has no number for this

The two frames

2026 Polygon Siskiu T T6 UDH (M)The Polygon Siskiu T T6 UDH frame drawn to scale.J 1214

Only the Polygon Siskiu T T6 UDH is drawn. The Forbidden Reya Tier numbers we have for size S3 are missing the chainstay length.

Geometry side by side

MeasurementPolygon Siskiu T T6 UDH MForbidden Reya Tier S3Difference
Reach465475+10 mm
Stack609625+16 mm
Head tube angle64.565.0+0.5°
Seat tube angle71.273.4+2.2°
Effective top tube595619+24 mm
Chainstay length430not listed
Wheelbase12141244+30 mm
BB height337.5331−7 mm
Standover705719+14 mm
Seat tube length400440+40 mm
Head tube length95120+25 mm
Fork lengthnot listed541

Differences are the Forbidden Reya Tier minus the Polygon Siskiu T T6 UDH. Full charts: 2026 Polygon Siskiu T T6 UDH, 2026 Forbidden Reya Tier.

Where each sits in its class

Polygon Siskiu T T6 UDHForbidden Reya Tier

AggressivePositionUpright
CalmSteeringQuick
PlayfulBalancePlanted

Each bike is ranked against the other trail bikes on Quiver, on frame geometry alone. Not your hand position or ride feel.

What each ships with

The stock build of each bike's first listed trim. Parts that match are dimmed.

PartPolygon Siskiu T T6 UDHT6 with UDHForbidden Reya TierTier 1
FramePolygon ALX TrailForbidden Reya
ForkRockShox Recon Silver TKFox 34 Factory SL
Rear shockX-Fusion O2 ProFox Float Factory
ShifterShimano CUESSRAM Pod Rocker Controller
DerailleurShimano CUESSRAM XX XX SL
CassetteShimano CUESSRAM XX SL Eagle Transmission
ChainKMC XGlideSRAM XX SL
CranksetSamox RAC61CSRAM XX SL
PedalsPolygon Expertnot listed
WheelsetPolygon MT6not listed
TireMaxxis DissectorMaxxis Rekon Race
BrakeShimano MT200SRAM Motive Ultimate
RotorShimano SM-RT10SRAM HS2
HandlebarPolygon EXPERTOneUp Components Carbon
StemPolygon EXPERTBikeYoke Barkeeper Stem
HeadsetFSA No 57ECane Creek 40
Dropper postX-Fusion MANIC LCOneUp Components V3 Dropper Post
SaddleLinc XTENTfizik Terra Ridon X1
Chainringnot listedSRAM 32T
Bottom bracketnot listedSRAM DUB
Batterynot listedSRAM AXS EP Powerpack
Hubnot listedDT Swiss 240 SPLINE, DT Swiss 240 SPLINE Ratchet EXP
Rimnot listedDT Swiss 1500

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