2021 Rocky Mountain Altitude Alloy (27.5) vs 2021 Giant Reign Advanced Pro
The XL is the Giant Reign Advanced Pro size closest to your XL Rocky Mountain Altitude Alloy (27.5). 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 Giant Reign Advanced Pro
Compared with the Rocky Mountain Altitude Alloy (27.5) in XL, the Giant Reign Advanced Pro in XL places the top of the head tube 9 mm lower and 3 mm further forward, relative to the bottom bracket. Its wheelbase is 4 mm longer, which can contribute to stability at speed.
- Frame stack
- −9 mm
- Lower front end
- Frame reach
- +3 mm
- Longer frame reach
- Wheelbase
- +4 mm
- Longer: steadier at speed
- Head angle
- −0.2°
- About the same head angle
- Chainstays
- +2 mm
- About the same
The two frames
Rocky Mountain Altitude Alloy (27.5), XLGiant Reign Advanced Pro, XLDrawn to scale and lined up at the bottom bracket.
Geometry side by side
| Measurement | Rocky Mountain Altitude Alloy (27.5) XL | Giant Reign Advanced Pro XL | Difference |
|---|---|---|---|
| Reach | 508 | 511 | +3 mm |
| Stack | 649 | 640 | −9 mm |
| Head tube angle | 64.8 | 64.6 | −0.2° |
| Seat tube angle | 75.8 | 76.4 | +0.6° |
| Effective top tube | 672 | 666 | −6 mm |
| Chainstay length | 437 | 439 | +2 mm |
| Wheelbase | 1285 | 1289 | +4 mm |
| BB drop | 30 | 27 | −3 mm |
| Standover | 815 | 804 | −11 mm |
| Seat tube length | 480 | 496 | +16 mm |
| Head tube length | 125 | 120 | −5 mm |
Differences are the Giant Reign Advanced Pro minus the Rocky Mountain Altitude Alloy (27.5). Full charts: 2021 Rocky Mountain Altitude Alloy (27.5), 2021 Giant Reign Advanced Pro.
Where each sits in its class
Rocky Mountain Altitude Alloy (27.5)Giant Reign Advanced Pro
Each bike is ranked against the other enduro 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 | Rocky Mountain Altitude Alloy (27.5)Alloy 50 (27.5) | Giant Reign Advanced ProAdvanced Pro 0 |
|---|---|---|
| Fork | Fox 36 Performance | Fox 38 Factory |
| Rear shock | Fox DPX2 Performance | Fox DHX2 Factory |
| Chain | Shimano Deore M6100 | Shimano XTR |
| Crankset | Race Face Aeffect Cinch | Shimano XTR M9100 |
| Tire | Maxxis Assegai, Maxxis Minion DHR II | Maxxis Assegai, Maxxis Minion DHR II DD |
| Hub | Rocky Mountain Sealed Boost, DT Swiss 370 | not listed |
| Rim | WTB ST i30 | not listed |
| Rotor | Shimano SM-RT66 | Shimano XTR |
| Dropper post | Race Face Aeffect R | not listed |
| Frame | not listed | Giant Reign |
| Shifter | not listed | Shimano XTR M9100 |
| Derailleur | not listed | Shimano XTR M9100 |
| Cassette | not listed | Shimano XTR M9100 |
| Wheelset | not listed | Giant TRX 0 |
| Brake | not listed | Shimano XTR M9120 |
| Handlebar | not listed | Giant Contact SLR |
| Stem | not listed | Giant Contact SL |
| Seatpost | not listed | Fox Transfer Factory |
| Saddle | not listed | Giant Romero SL |
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