Overview
The 2025 Transition Spire is Trail Town’s most aggressive offering—a full enduro machine with 170mm of rear and front travel. The Spire features a flip chip geometry adjustment (High/Low) that tweaks head angle (63°/62.5°), reach, and BB drop, allowing riders to dial their perfect setup. Five sizes span SM to XXL, ensuring optimal fit across the board.
Geometry Table
| Measurement | SM | MD | LG | XL | XXL |
|---|---|---|---|---|---|
| Reach (mm) | 430 | 460 | 485 | 510 | 535 |
| Stack (mm) | 619 | 619 | 628 | 637 | 646 |
| Seat Tube Length (mm) | 360 | 390 | 430 | 460 | 490 |
| Eff. Seat Angle | 79.6° | 78.8° | 78.1° | 77.5° | 77.2° |
| Head Tube Angle | 63° | 63° | 63° | 63° | 63° |
| Head Tube Length (mm) | 100 | 100 | 110 | 120 | 130 |
| Chainstay (mm) | 446 | 446 | 446 | 452 | 452 |
| Wheelbase (mm) | 1227 | 1257 | 1287 | 1322 | 1352 |
| BB Drop (mm) | 25 | 25 | 25 | 25 | 25 |
| BB Height (mm) | 350 | 350 | 350 | 350 | 350 |
Geometry Diagram
Detailed geometry specifications from manufacturer data. Contact the manufacturer for complete, size-specific measurements or visit their official website.
Key Specs
Frame: Aluminum/Carbon, 170mm rear travel, flip chip adjustable. Fork: RockShox Lyrik Ultimate, 170mm. Shock: RockShox Super Deluxe Ultimate. Drivetrain: SRAM XX1 Eagle AXS 12-speed. Brakes: SRAM Code Ultimate, 220mm/200mm. Weight: ~15.84kg (aluminum MD). Advanced suspension platform with progressive geometry.
Ride Characteristics
The Spire is confident and composed. The generous 170mm travel duo soaks up almost anything short of free fall. In High mode (63° HTA, 25mm BB drop), the Spire feels stable and predictable. In Low mode (62.5° HTA, 32mm BB drop), it becomes a plush descending machine. The flip chip adjustability means you can dial the exact character you want for your local terrain. Climbs are surprisingly efficient thanks to the steep seat tube angle and responsive suspension.
Comparable Models
The Transition Spire 2025 competes with: Trek Slash, Santa Cruz Megatower, Specialized Enduro, Norco Range, Evil Wreckoning.
Frequently Asked Questions
What does the Spire’s flip chip do?
The flip chip adjusts the head tube angle (63° vs 62.5°), reach, and BB drop (25mm vs 32mm). High mode is more neutral and snappy; Low mode is slack and planted.
How much does head angle change with flip chip?
The difference is 0.5°, which may seem small, but combined with reach and BB drop changes, it creates noticeably different ride characteristics.
Is the Spire compatible with mullet setups?
The Spire is designed for full 29″ wheels. Mullet compatibility is not supported by Transition for this model.
What sizes does the Spire come in?
Five sizes: SM, MD, LG, XL, and XXL, ranging from approximately 5’2″ to 6’8″.
How much travel does the Spire have?
The Spire is a true enduro bike with 170mm of rear travel paired with a 170mm fork, making it one of Transition’s longest-travel options.
Related Geometry
More Transition geometry: Transition Patrol 2026 Geometry, Transition Sentinel 2025 Geometry.
Compare enduro bikes: 2023 Giant Reign Geometry, 2023 Giant Reign SX Geometry, 2023 Norco Range Geometry.