2021 Decathlon RockRider ST 900
- Category
- Hardtail Trail MTB
- Design
- Flat Bar, Hardtail (Front suspension)
- Frame
- Aluminum
- Fork
- Steel
- Suspension
- 120mm fork travel
Average stack and reachvs category Suspension sag unknown Geometry may mis-represent actual riding geometry | Average stack and reachvs category Suspension sag unknown Geometry may mis-represent actual riding geometry | Average stack and reachvs category Suspension sag unknown Geometry may mis-represent actual riding geometry | Average stack and reachvs category Suspension sag unknown Geometry may mis-represent actual riding geometry |
Geometry
Small | Medium | Large | X Large | |
Stack | 591mm | 610mm | 614mm | 629mm |
Reach | 377mm | 402mm | 429mm | 446mm |
Stack to Reach Ratio | 1.57:1 | 1.52:1 | 1.43:1 | 1.41:1 |
Seat Tube Length, Unknown | 421mm | 432mm | 443mm | 493mm |
Top Tube Length, Effective/Horizontal Unknown | 558mm | 588mm | 618mm | 638mm |
Top Tube Slope | 20.6deg | 20.4deg | 18.8deg | 15deg |
Head Tube Angle | 69.5deg | 69.5deg | 69.5deg | 69.5deg |
Seat Tube Angle | 73deg | 73deg | 73deg | 73deg |
Head Tube Length | 104mm | 124mm | 129mm | 144mm |
Bottom Bracket Drop | 43mm | 43mm | 43mm | 43mm |
Bottom Bracket Height | 302.3mm | 302.3mm | 302.3mm | 302.3mm |
Chainstay Length Horizontal | 430mm | 430mm | 430mm | 430mm |
Front-Center | 630.5mm | 662.4mm | 692.3mm | 713.3mm |
Front-Center Horizontal | 629mm | 661mm | 691mm | 712mm |
Wheelbase | 1059mm | 1091mm | 1121mm | 1142mm |
Fork Offset/Rake | 44mm | 44mm | 44mm | 44mm |
Trail | 82.1mm very high | 82.1mm very high | 82.1mm very high | 82.1mm very high |
Mechanical Trail | 76.9mm | 76.9mm | 76.9mm | 76.9mm |
Wheel Flop | 27mm | 27mm | 27mm | 27mm |
Tire to Pedal Spindle | 115.1mm 170 mm cranks | 147.1mm 170 mm cranks | 177mm 170 mm cranks | 198mm 170 mm cranks |
Pedal Spindle to Ground Clearance | 132.3mm 170 mm cranks | 132.3mm 170 mm cranks | 132.3mm 170 mm cranks | 132.3mm 170 mm cranks |
ST 900 Build
Small | Medium | Large | X Large | |
Wheel Size | 650B/27.5 in 584 mm BSD | 650B/27.5 in 584 mm BSD | 650B/27.5 in 584 mm BSD | 650B/27.5 in 584 mm BSD |
Tire Width | 2.1in | 2.1in | 2.1in | 2.1in |
Tire Outer Diameter | 690.7mm | 690.7mm | 690.7mm | 690.7mm |
Bike Length with Tires | 1749.7mm | 1781.7mm | 1811.7mm | 1832.7mm |
Handlebar Width | 720mm | 720mm | 720mm | 720mm |
Stem Length | 70mm | 80mm | 80mm | 90mm |
Published Sizing Recommendations
Height | 150 cm to 164 cm | 165 cm to 174 cm | 175 cm to 184 cm | 185 cm to 200 cm |
Stack and Reach vs. Category Trend
Very Upright
Somewhat Upright
Average
Somewhat Aggressive
Very Aggressive
The Bike Insights Upright/Aggressive scale is based on analysis of a bike’s proportions relative to similar sized bikes in the same category.
Learn more about the Upright/Aggressive ScaleCategory Trend
Hardtail Trail MTBSource:https://www.decathlon.it/p/mtb-st-900-27-5/_/R-p-301098?mc=8500763&c=GRIGIO