Old vs. new: Sram XX Eagle Transmission vs. Sram Eagle XX1 AXS in comparison
Henri Lesewitz
· 21.03.2023
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With Transmission, Sram presents the next evolutionary stage of the proven Eagle AXS drivetrain. The number of innovative details is astounding, but at its core, much has remained the same. Transmission offers 12 gears like the classic XX1 AXS. Gears are also shifted wirelessly and the batteries are the same. Transmission does not replace the old AXS drivetrains, but complements them. The price difference between the XX1 AXS groupset and the 2450 euro XX Transmission is a whopping 500 euros. What is the actual difference between the two high-end drivetrains? A comparison.
The rear derailleur
The two Eagle rear derailleurs are visually very different. However, the decisive innovation is a rather small detail that most people probably overlook at first: Unlike the classic XX1 rear derailleur, the Transmission rear derailleur has a UDH link. This means that it is bolted directly to the UDH dropout of the frame and not, like XX1 AXS, to a classic derailleur hanger. Advantage: The distance between the rear derailleur and cassette is always optimised. This is why the Transmission rear derailleur has no adjustment screws. Neither a wrap screw. Nor upper and lower stop screws. Another innovation of the new Transmission rear derailleur is the large, lower derailleur pulley called Magic Wheel. The outer toothed ring is mounted on a floating bearing. If a stick gets jammed in the cog, the outer toothed ring continues to rotate and thus protects the cage from damage.
Advantage of Transmission: Thanks to UDH, the rear derailleur sits rock-solid because it is bolted to the frame from both sides. It is less affected by impacts, so that it does not normally need to be readjusted. There is no derailleur hanger that can bend. Disadvantage: The Transmission rear derailleur can only be fitted to new frames that have a UDH link.
The cassette
A great deal of engineering power was invested in the development of the transmission cassette. The innovation that immediately catches the eye is the more harmonious gradation. Instead of a 36 and a 42 sprocket, there is now a 38 and a 44 sprocket. As with the classic XX1 cassette, the XX Transmission version also consists of eleven steel sprockets and one aluminium sprocket. With 10/52 teeth, the range remains at the usual 520 per cent. The freewheel system (XD) also remains the same. However, due to the slightly different position of the sprockets, the Transmission cassette can only be combined with parts from the Transmission series XX SL, XX and X.0. Transmission was developed as a system (T-Type). The focus was on optimised shifting performance. Our tests have confirmed that the Transmission system shifts more smoothly, especially under full load.
Striking: The red-coloured setup sprocket. This is where the chain is placed during assembly. Once all the steps have been completed and everything has been tightened, the gears work perfectly and no longer need to be adjusted. In contrast to the older XX1 versions, the new cassettes are only available in a monochrome look and no longer in dazzlingly bright colours.
The weight of the XX1 cassette is 379 grams. The XX Transmission is exactly as heavy or light. The price jump from old to new is significant. While the recommended retail price of the XX1 cassette is 490 euros, the XX Transmission cassette 660 Euro. For the even more sophisticated light version SL, you even have to fork out an insane 720 euros (>> e.g. available here).
The controller
The controller is somewhat chunkier than the previous version. The new two-button switch also protrudes more from the handlebars than the older rocker switch. However, the operation of the new controller is significantly better and more intuitive. Plus point transmission! Also great: the two-button levers can be perfectly adjusted according to personal preference. The electronics inside have largely remained the same. The operating time of the installed button cells should therefore be virtually identical.
The transmission controller is available as a deluxe version with interchangeable buttons (convex or concave shape) and for mounting on the left or right if you ride the radio-controlled Rockshox Reverb AXS post.
The crank
Like the classic XX1, the XX Transmission crank combines lightweight construction, rigidity and elegance. The biggest difference is the new 8-hole direct mount for the chainring. The new mount makes it easy to retrofit the power meter. Otherwise, the new XX Transmission cranks have a T-type chainring and can be retrofitted with stylish, bolt-on bash guards. The Transmission cranks, which are made of carbon with a foam core, are a few grams heavier than the XX1.
The chain
The specially developed flattop chain from the Transmission Group is the final piece of the T-Type system puzzle. The completely straight outer line is striking. This is reminiscent of Sram's road bike chains, which are not compatible with the mountain bike drivetrain. The flattop chain of the XX Transmission version has hollow rivets and is hard chrome-plated like the XX1 chain. As with the cassettes, the price jump is enormous. While the XX1, with a recommended retail price of 96 euros, marked the upper price limit for years, the XX Transmission chain virtually blows up the previous level. 150 euros should make many bikers gulp. The Premium version SL even costs 180 euros.
Like the cassettes, the transmission chains are only available in a monochrome look, while the XX1 chains in rainbow or gold look are real eye-catchers.
Sram: Transmission vs. AXS - BIKE editors' verdict
Many innovations, but not a huge difference. Sram's transmission group is more evolution than revolution. In practice, the improvements are noticeable in the form of smoother shifting. Whether this is worth the hefty surcharge for the Sram XX Transmission is up to you to decide. - Henri Lesewitz, BIKE Editor-in-Chief
