![Mystery prototype rear derailleur seen on Molly Cameron's Focus Mares. © Clifford Lee / Cyclocross Magazine](https://www.cxmagazine.com/wp-content/uploads/2016/10/molly-cameron-prototype-rear-derailleur-dsc_0413-cxmagazine_1-750x579.jpg)
Mystery prototype rear derailleur seen on Molly Cameron’s Focus Mares. © Clifford Lee / Cyclocross Magazine
Molly Cameron came in second at the 2016 CrossVegas’ Wheelers and Dealers race, falling just short of defending the 2015 title. Cameron was racing her Shimano Ultegra 6800-equipped Focus Mares that looked similar to the model we reviewed in Issue 27. Her bike was equipped with TRP CX 8.5 mini-V brakes and Challenge Team Edition Grifo tires on Enve tubular wheels, but most intriguing was the drivetrain. Molly was running Shimano STI 11-speed shifters with a single chainring up front and an unmarked rear derailleur.
![Mystery prototype rear derailleur is CNC machined, and reminds us of 90s mountain bike components from Paul Component and others. Seen on Molly Cameron's Focus Mares. © Clifford Lee / Cyclocross Magazine](https://www.cxmagazine.com/wp-content/uploads/2016/10/molly-cameron-prototype-rear-derailleur-dsc_0418-cxmagazine_1-750x531.jpg)
Mystery prototype rear derailleur is CNC machined, and reminds us of 90s mountain bike components from Paul Component and others. Seen on Molly Cameron’s Focus Mares. © Clifford Lee / Cyclocross Magazine
The mechanism is machined aluminum with a raw finish and bolted together. The bulky part of the B-knuckle is machined out, as is the front plate. It seems to use slant-parallelogram geometry with a medium length pulley cage.
The upper pulley is coincident with the upper return spring, housed within a black plastic cover. I swung the pulley cage forward and felt stiff spring tension with progressive resistance—likely a “clutch” mechanism of some sort for better chain retention for single chainring 1X drivetrains.
![The prototype appears to use a slant parallelagram geometry (unlike SRAM's 1X derailleurs) with a clutch-type mechanism coincident with the top pulley. Mystery prototype rear derailleur seen on Molly Cameron's Focus Mares. © Clifford Lee / Cyclocross Magazine](https://www.cxmagazine.com/wp-content/uploads/2016/10/molly-cameron-prototype-rear-derailleur-dsc_0419-cxmagazine_1-750x526.jpg)
The prototype appears to use a slant parallelagram geometry (unlike SRAM’s 1X derailleurs) with a clutch-type mechanism coincident with the top pulley. Mystery prototype rear derailleur seen on Molly Cameron’s Focus Mares. © Clifford Lee / Cyclocross Magazine
It’s clear that this is a prototype derailleur, but made by which company? Cameron was sponsored by Shimano, Enve, and TRP in the past. Cameron was mum on the topic, but we’re guessing it’s either a prototype from TRP or perhaps Shimano, as the former has dabbled in drivetrain components, while Shimano has yet to offer a clutch derailleur for its road shifters (unless you pair an XTR Di2 rear derailleur with Di2 road shifters).
![Mystery prototype rear derailleur seen on Molly Cameron's Focus Mares. © Clifford Lee / Cyclocross Magazine](https://www.cxmagazine.com/wp-content/uploads/2016/10/molly-cameron-prototype-rear-derailleur-dsc_0421-cxmagazine_1-750x802.jpg)
Mystery prototype rear derailleur seen on Molly Cameron’s Focus Mares. © Clifford Lee / Cyclocross Magazine
Using a Shimano clutch-based rear derailleur with a drop handlebar bike is already possible with some creative solutions. Gevenalle offers its GX shifters that pair nicely Shimano Dyna-Sys rear derailleurs, Wolf Tooth has its Tan Pan pulley that pairs Shimano road shifters with Shimano mountain bike derailleurs, and then of course there’s the tried-and-true method that Sven Nys used the last few seasons—a guard and watcher.
Add another option to that list, if you’re fortunate to have access to a manufacturer’s prototypes.