Sigma

Sigma Cadence Transmitter STS Bicycle Computer

Name: Sigma Cadence Transmitter STS Bicycle Computer
Brand: Sigma
SKU: Cadence Transmitter STS

★★★★★4.5 (226 reviews)

Wireless cadence data for your Sigma computer — clip the sensor, mount the magnet, and get pedaling metrics without cable clutter.

$40.99*

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*Price sourced from Amazon.com. Last updated:Jul 14, 2026.Price and availability are subject to change.

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Overview

The Sigma STS Cadence Transmitter Kit is a wireless cadence sensor designed to deliver revolutions-per-minute data to compatible Sigma STS bike computers. Using Sigma's proprietary STS transmission protocol, the sensor mounts to the bike frame via a swivelling bracket while a spoke magnet attaches to a rear wheel spoke — each revolution passing the magnet by the sensor generates a cadence signal, which the head unit processes into real-time RPM data. The wireless design removes the spoke-to-fork cable routing that wired cadence sensors require, which matters on performance builds where clean cable management affects both aesthetics and the risk of cable interference. The waterproof rating ensures the transmitter survives the conditions that road and trail riding actually produces.

This transmitter is purpose-built for the Sigma STS ecosystem, compatible with the BC 14.16 STS, BC 14.16 STS CAD, BC 16.16 STS, BC 16.16 STS CAD, and BC 23.16 STS computers. For cyclists already training with one of these head units, the STS Cadence Transmitter adds cadence data — a key training metric for optimizing pedaling efficiency and managing fatigue — without requiring a new computer. The swivelling bracket design allows enough angular adjustment to achieve the tight sensor-to-magnet clearance needed for reliable pickup on frames with varying tube profiles. It is a single-function sensor; riders who want simultaneous speed data will need a compatible speed transmitter alongside it.

Specifications

Brand

Sigma

Product Type

Bicycle Computer

Pros & Cons

👍 Pros

Wireless STS transmission eliminates spoke-to-fork sensor cables, simplifying installation and reducing cable management on the bike
Waterproof construction handles real-world riding conditions including rain and road spray without signal dropout or hardware damage
Swivelling bracket allows precise sensor-to-magnet gap adjustment for reliable cadence pickup across different frame tube diameters and spoke configurations
Spoke magnet mounting is a proven, low-failure cadence measurement method that remains accurate regardless of wheel size or tire width
Compatibility across five BC-series STS computers means it integrates directly with existing Sigma head units without a new computer purchase

👎 Cons

Proprietary STS wireless protocol locks the transmitter to Sigma STS-compatible computers only — it will not work with ANT+ or Bluetooth head units, limiting future computer upgrades to the Sigma STS ecosystem
Measures cadence only — a separate speed transmitter is required for riders who want full speed and cadence data simultaneously
Spoke magnet placement requires the wheel to be nearby the sensor at all times — wheel removal for maintenance requires remounting and re-gapping the sensor on reassembly
No stated battery life specification makes it difficult to plan replacement intervals before a ride

Frequently Asked Questions

Which Sigma bike computers does the STS Cadence Transmitter actually work with?

The transmitter is compatible with the BC 14.16 STS, BC 14.16 STS CAD, BC 16.16 STS, BC 16.16 STS CAD, and BC 23.16 STS models. It uses Sigma's STS (Sigma Transmission System) wireless protocol, which is proprietary — it will not pair with ANT+ or Bluetooth-based head units from other brands or Sigma's non-STS computers.

How is the cadence transmitter mounted to the bike?

The transmitter uses a swivelling bracket that clamps to the chainstay or seatstay, and a spoke magnet mounts to a rear wheel spoke. Each pedal revolution passes the magnet by the sensor, triggering a cadence count. The swivelling bracket allows the sensor to be angled to minimize the gap between sensor and magnet for reliable signal pickup.

Is the STS Cadence Transmitter waterproof enough for riding in rain?

Yes — the transmitter is rated waterproof, making it suitable for riding in rain and wet road conditions. It is not designed for full submersion, but normal outdoor cycling exposure including puddles and heavy rain is within its operating parameters.

Does this transmitter also measure speed, or only cadence?

This transmitter measures cadence only — it counts crank revolutions per minute using the spoke magnet passing the sensor. Speed measurement on compatible Sigma STS computers is handled by a separate speed sensor or by the computer's GPS functionality, depending on the model. Check your computer's documentation to confirm whether a combined speed/cadence sensor is available for your specific model.

What battery does the transmitter use, and how long does it last?

Battery type and life are not specified in available product documentation. For accurate battery replacement information, consult the transmitter's included manual or Sigma's support resources.