SRAM’s Transmission drivetrains have been electronic-only since launch, but that may soon change. A newly published patent filing from January 30 strongly suggests that a mechanical, cable-actuated Transmission derailleur is in development.
Although prototype sightings have fueled speculation for months, both the language and exploded diagram in the patent confirms it further – this is a purely mechanical derailleur with no electronic components.
Much of the patent focuses on the biggest challenge in adapting Transmission to mechanical shifting: setup. Unlike traditional derailleurs mounted on hangers, Transmission bolts directly to the frame, eliminating fine-tuning via a B-tension screw. According to the patent, “precise initial adjustment of the B gap has a particularly significant influence on the robustness and switching performance,” or shift accuracy, of direct-mount derailleurs. The patent describes a blocking mechanism to address this: a hex key inserted into the parallelogram temporarily holds the derailleur in place while chain tension is adjusted.
This ensures the derailleur is positioned correctly before the mounting bolt is tightened to proper torque. The patent also says that different hex key sizes can be used on different frame geometries, particularly to accommodate variations in suspension kinematics.
The patent also suggests that SRAM is integrating cable tensioning and actuation into the derailleur to provide more consistent shifting performance with the direct-mount system.
Much like the electronic Transmission derailleurs, the mechanical version also seems to feature a modular derailleur cage, meaning the lower portion can be replaced separately, rather than requiring a full derailleur swap.
Last note about the patent; the two primary inventors listed on the patent – Heiko Redecker and Tobias Harcke – were also heavily involved in behind SRAM’s Universal Derailleur Hanger (UDH) and Transmission itself. Their involvement strongly suggests this is a fully considered extension of the Transmission platform.
With many high-end bikes now offered exclusively with electronic Transmission, a mechanical version could make the system more accessible to a wider range of riders – particularly those who prefer cable actuation over battery dependency.
Though SRAM has yet to make an official announcement, with 2026 model-year bikes already in production, a mechanical Transmission derailleur might not be far off.
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