SRAM Transmission Six Months Down The Trail
In March of 2023, SRAM set a new bar for high performance 12-speed mountain drivetrains with their Transmission lineup. The claims to fame with this new system according to SRAM are increased reliability and durability, as well as the best shifting performance when under load, compared to competing drivetrains. Over the first few weeks of use, our impression is that SRAM's claims hold up. But what about performance over the long haul? Over the past six months, we've had the opportunity to ride, abuse, and really get accustomed to the Transmission setup, so we can give you an idea of how well the system holds up and help you determine if it is worth the cost of admission.
The SRAM Transmission system is available in four different configurations: XX-SL, for XC racers looking for maximum performance and lowest weight, XX for racers that want the extra durability with a slight weight penalty, XO for riders looking for the best all-round performance, and GX, the most economical option in the lineup.
The most unique aspect of the Transmission system is the absence of the traditional derailleur hanger. Transmission mounts the rear derailleur directly to the frame instead. All four component levels have interchangeable parts and can be mixed and matched to get the exact drivetrain you want, depending on budget and preference. The Transmission cassette is a 12-speed 10-52t unit, providing a wide gear range for all terrains.
Who’s Riding it
We are lucky to have four riders here at the shop running Transmission on their bikes. Ryan is riding an Orbea Oiz with a mixture of XO and XX parts, Mat has XX-SL installed on his Santa Cruz Blur, Alison has a SCOTT Solace ERide with XO Transmission and I have GX level Transmission on my SCOTT Spark ST. The four different setups on these bikes have given us a good look at how the Transmission setup performs and holds up across each level, even including subjecting it to the added torque of an eBike motor.
We're riding a variety of setups on different bikes here at the shop, and we all agree that the Transmission system is universally good. You need a little time on the system to see how well it performs, as a short test ride doesn't really do it justice. The system's performance really becomes evident on the trails when you are pedaling harder than you would during a quick test ride on the asphalt. As you ride and climb longer and your legs get a little weaker, the shifting just gets better and feels even more consistent. It was noteworthy to realize that you can shift whenever you want, without worrying about jamming your chain or causing damage to the drivetrain.
Along with Transmission's shifting performance is the benefit of the increased durability. I have been riding my SCOTT Spark really hard, and I have had some sort of issue with everything on the bike, with the exception of the drivetrain. I've had to true my wheels, true my rotors, chase down brake noise, and fix a creak in my headset, all while my shifting has worked flawlessly at every call. This has given me a nice sense of security when riding, so I am not as worried when I hear my derailleur smack a rock. I am still running the stock chain, cassette, and derailleur that came with the bike, and I haven’t had to replace any parts internally either. I have been taking good care of it, with regular washes and lubes, but compared to my previous SRAM GX AXS system, it is standing the test of time better.
Transmission does take some getting used to. At low pedaling watts, the shifting can be a bit clunky and the chain occasionally feels like it might jump, but it has yet to actually happen to me. Because the entire cassette has been machined using SRAM's X-Sync technology, the system relies on some pedaling power to help it grab the next gear. The X-Sync machining, combined with the flat top chain design keeps your chain consistently engaged and eliminates chain drops. On the off chance a chain drop does occur, it can be just a bit harder to clear the jam than with other 1x systems.
Because of the added torque needed to shift Transmission, it doesn’t shift as quickly, but rather emphasizes quality shifts. When we asked Ryan for his impression of the Transmission system, he replied “(Transmission) definitely shifts better under load, but it took a little to get used to the slightly slower shifting.” Ryan also said it was “nice to know that my derailleur can take a beating.” This is one of the most common compliments the system, not having to tweak your bike every time you go to ride due to whatever rock you hit on your last ride. Mat added, “This is the best drivetrain I have ever ridden, there is no going back.”
On the eMtb side, the added torque of the drive system is actually beneficial to the performance of the Transmission drivetrain. Since it works better at higher watts, it's perfect for an eMtb because you're never pedaling in a low watt scenario (due to the motor). Drivetrain wear and tear will occur more quickly when used on an eMtb, but that is typical for any drivetrain on an eBike. For those who want a durable drivetrain for their eMtb, Transmission will still be perfect for you. Alison has been riding a drop-bar configuration on her E-Gravel bike, with SRAM Rival AXS road levers paired to the Transmission XO derailleur and cassette, and she has been pleasantly surprised with the uphill performance as she is shifting under load.
Another thing that took a little getting used to with Transmission was trying to figure out exactly which crankset is compatible with each bike. The use of SRAM DUB Wide, DUB, and different offset chainrings with a lack of extensive documentation on compatibility led to some hair pulling trial and error, but once installed on the bike, those issues melted away.
SRAM’s Transmission drivetrain is proving itself to be high-quality, durable, and reliable. We recommend it on anything Mountain, Gravel, or Electric versions of either. For people who love to do steep climbs or ride on rougher terrain, the Transmission system is a solid choice because of its performance under load and its remarkable ability to keep the chain on the bike. If you're interested in upgrading to Transmission, all you have to do is make sure your frame is UDH (Universal Derailleur Hanger) compatible and then give us a call. We are happy to assist you with your Transmission conversion, or anything else you need for your bike! Swing in to either location, or call us to get the process started.