Michael Hanslip Coaching

If you want to go faster, you have to pedal harder

AXS Transmission

When SRAM introduced the universal derailleur hanger, I don't know if they knew where it was going, but it seemed a great idea. If you've ever broken a derailleur hanger you will know that there were about 1000 different models and it has to be the exact one. The whole idea of the UDH was that one derailleur hanger fitting on a standardised attachment on the frame meant any new bikes built to this standard could use any new UDH. A good start.
The bonus now is that those frames can remove their UDH and replace it with a Transmission rear derailleur. I've seen three or four videos of reviewers standing on the derailleur to demonstrate who solidly it is attached to the frame. The derailleur is anchored into the through-axle system so it is robust and secure.
Because there is no hanger, there is no B-tension screw. The derailleur has been redesigned to be set in a particular position during setup and then it remains there statically. There is a red sprocket on the cassette that reminds the mechanic which gear to set up the derailleur in. The derailleur is so tough that a collision with typical rocks or trees might not damage it at all, but if it does it won't be ripping the derailleur from the frame. And some sub-components of the derailleur are sold individually for rebuilding after a collision.
Also because of the way the derailleur is setup and because there is only one cassette it works with, there are no inner or outer limit screws either. Suntour invented the slant-parallelogram rear derailleur about 50 years ago. This is perhaps not as revolutionary as that, or perhaps it is. A big step forwards.
The new Transmission cassette and flat-top chain will only shift in the shifting windows. Hyperglide introduced us to the idea of shifting windows back in about 1990. The Transmission uses taller than normal teeth for all but the shifting teeth, so there can be no shifting except where designed. That can be perceived as a delay in the shift - waiting for it to come around. Several users I know don't complain about it and it seems fine to me.
Eagle was the name applied to everything new when SRAM went 12-speed. "Eagle Technology" SRAM called it. Given there is no real cross-over compatibility with Eagle and Transmission, they really ought to have called it another bird name (Condor for better soaring? Falcon for higher speed?). Naming oddities aside, Transmission seems a good step forward for AXS MTB drivetrains.