2026 Polygon Siskiu T T8 UDH vs 2025 Trek Fuel EX
The ML is the Trek Fuel EX size closest to your L Polygon Siskiu T T8 UDH. We match frame stack and reach. This is a geometry comparison, not a fit recommendation; stem, spacers, handlebars and saddle setup also affect your riding position.
What changes on the Trek Fuel EX
Compared with the Polygon Siskiu T T8 UDH in L, the Trek Fuel EX in ML places the top of the head tube 5 mm lower and 15 mm further back, relative to the bottom bracket. Its wheelbase is 7 mm shorter, which can contribute to quicker direction changes.
- Frame stack
- −5 mm
- Lower front end
- Frame reach
- −15 mm
- Shorter frame reach
- Wheelbase
- −7 mm
- Shorter: quicker to change direction
- Head angle
- ±0.0°
- About the same head angle
- Chainstays
- +8 mm
- Longer: more planted
The two frames
Only the Polygon Siskiu T T8 UDH is drawn. The Trek Fuel EX numbers we have for size ML are missing the seat angle.
Geometry side by side
| Measurement | Polygon Siskiu T T8 UDH L | Trek Fuel EX ML | Difference |
|---|---|---|---|
| Reach | 485 | 470 | −15 mm |
| Stack | 622 | 616.8 | −5 mm |
| Head tube angle | 64.5 | 64.5 | ±0.0° |
| Seat tube angle | 71.2 | not listed | |
| Effective top tube | 619 | 607.4 | −12 mm |
| Chainstay length | 432 | 440 | +8 mm |
| Wheelbase | 1240 | 1233.1 | −7 mm |
| BB height | 337.5 | 335 | −3 mm |
| Standover | 711 | 741.8 | +31 mm |
| Seat tube length | 415 | 420 | +5 mm |
| Head tube length | 110 | 100 | −10 mm |
| BB drop | not listed | 38 |
Differences are the Trek Fuel EX minus the Polygon Siskiu T T8 UDH. Full charts: 2026 Polygon Siskiu T T8 UDH, 2025 Trek Fuel EX.
Where each sits in its class
Polygon Siskiu T T8 UDHTrek Fuel EX
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.
| Part | Polygon Siskiu T T8 UDHT8 with UDH | Trek Fuel EX5 |
|---|---|---|
| Frame | Polygon ALX Trail | Trek Fuel EX |
| Fork | Fox 34 Performance | RockShox Recon Silver |
| Rear shock | Fox Float | X-Fusion Pro 2 |
| Shifter | Shimano SLX M7100 | Shimano Deore M6100 |
| Derailleur | Shimano SLX M7100 | Shimano Deore M6100 |
| Cassette | Shimano SLX M7100 | Shimano Deore M6100 |
| Chain | KMC X-12 | Shimano Deore M6100 |
| Crankset | Shimano Deore M6120 | Shimano MT512 |
| Wheelset | Polygon MT6 | Bontrager Line TLR 30 |
| Tire | Maxxis Dissector | Bontrager Gunnison Elite XR |
| Brake | Shimano Deore M4100 | Shimano MT200 |
| Rotor | Shimano SM-RT54 | Shimano SM-RT56 |
| Handlebar | Polygon EXPERT | TranzX JD-YSI-22PLQ |
| Stem | Polygon EXPERT | Bontrager Comp |
| Headset | FSA No 57E | not listed |
| Dropper post | X-Fusion MANIC LC | TranzX JD-YSI-22PLQ |
| Saddle | Linc XTENT | Bontrager Arvada |
| Bottom bracket | not listed | Shimano MT501 |
| Grips | not listed | Bontrager XR Trail |
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