A patent application published this week hints that a SRAM Eagle Transmission-like mechanical derailleur could be coming to UDH-compatible bikes. The application was first filed July 15, 2024, and lists SRAM DEUTSCHLAND GmbH as both applicant and assignee, with Heiko Redecker and Tobias Harcke listed as the inventors. You can find the full patent application embedded below.
So what is different about the derailleur design?
Electronic SRAM Transmission derailleurs have notably done away with the B-screw which is used to adjust the gap between the top pulley and the cassette, aka the chain gap. This new hangerless, mechanical design also does away with the B-screw, instead using a hex-shaped blocking pin to temporarily set the derailleur in the proper position depending on the bike and configuration.
“Blocking of the derailleur can be achieved without significant technical complexity and even achieving a specific weight advantage,” according to the application. Once the derailleur has been set up, “the blocking member can then be removed simply by being pulled out of the receiving openings.”
“The entire pivot mechanism and consequently the derailleur is then secured in a desired blocking position. This is advantageous, in particular with purely mechanical derailleurs,” the application notes. “The blocking device to be configured in a simple, unobtrusive and less exposed manner compared with solutions from the prior art.”
Purported benefits
Aside from ease of setup, the patent application suggests this mechanical design offers some of the same benefits as existing electronic Transmission derailleurs, namely improved shifting stability. The patent application suggests that increased gear ranges found on modern cassettes, from 9T to 52T+, pose a challenge for traditional derailleur designs.
“In the event of sudden loads in a vertical direction, as occur when driving over rough terrain, such derailleurs can lead to an abrupt movement of the pivot mechanism and consequently to undesirable switching operations (so-called ‘ghost shifting’).”
The patent application notes that prior to this new design, optimal derailleur setup for a full suspension bike with a traditional B-screw derailleur required the bike to be in its sagged position. With this, a derailleur can be set without the use of a helper, or requiring the bike’s shock to be decompressed.
Mountain bikers appear to be split over electronic shifting, with many saying they prefer to use a mechanical system, and this could be welcome news to those riders. Still, this design represents a change over most current mechanical derailleurs that use a replaceable hanger, a part which this patent now suggests is “superfluous.”
Could this new design allow for even larger cassettes and extended gear ranges? Will hangerless mechanical derailleurs stand up to higher levels of abuse on the trail? Will the cost be significantly lower than current electronic derailleurs? For now, we can only speculate as it’s unknown how soon — or if — these types of derailleurs will be available for purchase.
Read through the patent application below and let us know if you find anything interesting that we may have missed!
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