Gen 1 Supercaliber/eCaliber Fox IsoStrut, Small Frame, 235mm x 32.5mm,Remote PTL

etailed Specifications:

• Brand: Fox Racing Shox

• Model: FLOAT IsoStrut Performance Series A Remote PTL (Push-to-Lock)

• Series: 2021 Performance Series — Black Anodized Finish

• Part Number: 972-61-257

• Example Serial Number: 1012985-0030-T (example only – may differ per unit)

• Frame Compatibility: Trek Supercaliber and eCaliber Gen 1 (Small frames only)

• Shock Length: 235 mm (Strut length)

• Damper Length: 135 mm

• Stroke / Travel: 32.5 mm

• Outer Diameter: 36 mm

• Rotation / Eyelet Angle: 60° (specific to Small frame geometry)

• Spacer Configuration: 0.1 Spacer

• Damper Type: Performance Series FLOAT IsoStrut Air Spring with Remote PTL Lockout

• Adjustments: External Rebound / 2-Position Remote Compression (Open / Lock)

• Axle Configuration: Proprietary Trek IsoStrut mount system (non-standard eye-to-eye)

• Material: Forged aluminum body, black anodized finish with hard-anodized stanchion

• Intended Use: XC Race / Marathon / Light Trail

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Additional Features:

• Performance Series tuning: Same internals as Factory Series but with a durable black-anodized finish (no Kashima coating) for maximum reliability.

• FLOAT air spring system offers tunable progression and excellent small-bump compliance.

• Remote PTL lockout enables rapid transitions between full-open and firm lock for climbing or sprinting.

• Integrated IsoStrut design mounts directly into the frame’s top tube for increased lateral stiffness and power transfer.

• Factory-valved specifically for Trek Supercaliber/eCaliber Gen 1 geometry to deliver balanced rear-end response.

• Performance-grade wiper seals and bushings for improved durability in mud and dust.

• Serviceable through any authorized Trek or Fox service center.

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Important Usage Notes:

• Fits Trek Supercaliber and eCaliber Gen 1 (Small) frames only.

• 60° rotation/eyelet orientation is specific to Small frames — not interchangeable with M/L sizes.

• Requires a Fox Remote Lockout Lever and cable (sold separately) for function.

• Not compatible with Gen 2 Supercaliber or any standard eye-to-eye rear shock.

• Installation must be performed by a qualified Trek or Fox technician to maintain alignment and warranty coverage.

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Riding Impressions:

The Fox FLOAT IsoStrut Performance Series transforms the Supercaliber/eCaliber Gen 1 platform into a race-tuned XC machine. Riders benefit from the FLOAT air spring’s smooth stroke and the Performance Series’ durable finish, ideal for dusty race courses and all-season training. The remote lockout delivers instant pedaling efficiency while the integrated strut layout preserves Trek’s signature rigid-frame feel with controlled traction.

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Disclosure:

This listing includes one genuine Fox FLOAT IsoStrut Performance Series A Remote PTL Rear Shock (235 mm).
Example serial number shown for reference; actual number may differ.
Non-retail packaged — includes only what is shown in photos.
Designed for Trek Supercaliber/eCaliber Gen 1 Small frames only.
Remote lockout lever, mount hardware, and bolts not included.
Professional installation recommended.