PORT CITY CREATIONS

Know Your Limits. Without Looking Down.

Pushing hard into a climb and you shift — but there’s nothing there. You’re already at your biggest cog, or SRAM’s cross-chain logic has blocked the next shift. You wasted a beat.

GearBeeper fixes that. It runs as a background extension on your Karoo head unit and plays a short, distinctive beep whenever you reach a cassette endpoint — physical or effective. You hear it. You know. You ride.

How It Works

GearBeeper listens to your SRAM AXS drivetrain in real time via the Karoo Extension SDK. When you shift into a boundary position, it plays a beep pattern you can identify by ear:

PositionAlert
Smallest physical cogTwo beeps, descending pitch
Largest physical cogTwo beeps, ascending pitch
Effective small end (cross-chain blocked)Three beeps, descending pitch
Effective large end (cross-chain blocked)Three beeps, ascending pitch

Each alert fires once when you enter the position. Shift away, shift back — it alerts again. No spam, no false positives.

Cross-Chain Awareness

SRAM AXS doesn’t let you use every gear combination. Certain big-ring/big-cog and small-ring/small-cog positions are intentionally blocked to protect your drivetrain from cross-chaining. GearBeeper understands these rules for every supported drivetrain and distinguishes between a hard cassette end and a soft cross-chain limit — because they feel different in the saddle, and you should know which one you’ve hit.

Supported Drivetrains

Road 2x

  • Red eTap AXS, Red eTap AXS Wide
  • Force eTap AXS
  • Rival eTap AXS, Rival eTap AXS Wide
  • Apex eTap AXS

Road 1x

  • Red eTap AXS 1x
  • Force eTap AXS 1x

MTB

  • Eagle AXS, Eagle AXS Wide
  • Transmission T-Type

Gravel

  • Force XPLR eTap AXS
  • Rival XPLR eTap AXS

Installation

GearBeeper is a Karoo Extension — it runs directly on your Karoo 2 or Karoo 3 head unit. No account, no configuration, no fuss.

Download GearBeeper →

Privacy

GearBeeper collects no data. It runs entirely on your Karoo device and communicates only with the Karoo OS extension API. Nothing is transmitted, stored, or tracked.

Support

Questions or issues? Email support@portcity.tech .


If GearBeeper is useful, you can buy me a coffee to help keep it going.