The PRO Tharsis Gap Cap Expander is a two-in-one headset top cap and Shimano Di2 battery holder for riders running an electronic groupset on a PRO Tharsis cockpit. It replaces your standard top cap, preloads the headset like an expander plug, and stows the internal Di2 battery neatly inside the fork steerer tube for a clean, wire-managed front end.

Highlights

  • Combined expander plug, headset top cap and Di2 battery holder in one unit
  • Holds a Shimano SM-BTR2 internal battery inside the fork steerer
  • Tharsis-specific black alloy cap to match the PRO Tharsis cockpit
  • Suits 1-1/8" steerer tubes
  • Supplied with mounting hardware, cable ties and an O-ring for a tidy install

Compatibility & fit

Designed for 1-1/8" steerer tubes and intended for use with the PRO Tharsis Di2 stem and Tharsis XC / Trail compatible cockpits. The fork steerer must be at least 180 mm long to safely house the battery. This is the Tharsis-specific version, supplied with the matching Tharsis top cap; a general (non-Tharsis) version is sold separately. Holds the Shimano SM-BTR2 Di2 battery. If you are unsure whether your stem or steerer length suits this part, contact Tune Cycles before fitting.

Covered by PRO's manufacturer warranty against defects in materials and workmanship. For any warranty claim or support, return the item to Tune Cycles and we will manage the process on your behalf.
  • Three-in-one design: expander plug, headset top cap and Di2 battery holder
  • Stores a Shimano SM-BTR2 Di2 battery inside the fork steerer tube
  • Tharsis-specific black alloy top cap to suit the PRO Tharsis cockpit
  • Fits 1-1/8" steerer tubes
  • Requires a minimum fork steerer length of 180 mm
  • Supplied with top cap and bolt, three cable ties, an O-ring and fitting manual
TypeExpander plug + headset top cap + Di2 battery holder
Steerer size1-1/8"
Battery heldShimano SM-BTR2 (internal Di2 battery)
Minimum fork steerer length180 mm
Cap material / finishAlloy, black
WeightApprox. 50 g
FitmentPRO Tharsis Di2 stem / Tharsis XC & Trail compatible cockpits (Tharsis-specific cap)
In the boxExpander/battery holder, top cap & bolt, three cable ties, O-ring, manual
SKU SHM-PRAC0261
Barcode # 8717009899956
Brand PRO