Sram GX Eagle Transmission review – is the upgrade worth it?

With the Sram GX Eagle Transmission, innovative T-Type technology is coming into affordable price regions. We reveal what the new Sram GX Eagle Transmission can do and compare it with the conventional AXS and the mechanical GX Eagle version. Is the upgrade worth it?

With the introduction of the 12-speed Eagle groupset, Sram has taken over technical supremacy. Even though Shimano, as the largest supplier to the bicycle industry, countered with a 12-speed offensive, the innovations in mountain bike shifting currently come out of Schweinfurt, Germany. Full stop. The recent presentation of the Sram XO and XX Eagle transmission has once again proved, that Shimano currently has little to counter Sram in terms of mountain bike innovations. After the front derailleur, the Americans from Sram have now also buried the derailleur hanger. The new T-Type drives are robust, can be repaired in small parts and make annoying adjustments superfluous. Despite these advances on several levels, criticism was clear at market launch. Sram, they said, was digging too deep into the pockets of the users for its innovations. The transmission drives, which are bolted directly to the frame without a derailleur hanger, were too expensive. That’s what we heard from everywhere. The GX Eagle Transmission is a cheaper transmission version, that has almost all the features of its big brothers. Can it stop the criticism from the scene?

The UDH derailleur hanger – the prerequisite for all transmission groupsets

Before getting excited about the price of Sram Transmission shifting systems, it’s important to understand what you’re paying for in the first place. Sram is not replacing the derailleur hanger, i.e. the previous connection between the rear derailleur and the frame, as means to an end. The goal behind it is clear: the engineers from Schweinfurt want to make shifting better. And to make the Eagle drivetrains, which already work very well, even better, they are getting down to the nitty-gritty, or rather the derailleur hanger. Even when Sram introduced the UDH (Universal Rear-Derailleur Hanger) to the market with a lot of fireworks, it was clear that there were greater goals behind it than a worldwide uniform supply of spare parts. This UDH derailleur hanger standard is ultimately the prerequisite for being able to install the new Sram Transmission derailleurs on one’s bike. Unlike conventional (non-UDH) derailleur hangers, the UDH derailleur hanger not only connects the frame and rear derailleur. It also contains the thread for the thru axle of the rear wheel. With this step, the position between the rear wheel axle (and thus also the cassette) and the rear derailleur is clearly defined once and for all.

Perfect setting from the factory: the great advantage of Sram Transmission (T-Type) groupset

Once it is clear where the rear derailleur is in relation to the cassette, all the stops and clearances can be perfectly adjusted from the factory. The manual adjustment of the upper or lower end is so redundant with the new transmission derailleur, that there are no longer any adjustment options for it. The same applies to the distance from the upper shifting roller to the sprocket, which in the past always had to be adjusted with a somewhat lumpy plastic template on all Eagle drives. In other words: Sram’s Eagle Transmission groupsets are perfectly adjusted ex works. The defined connection between thru axle and rear derailleur eliminates all variables and thus saves a lot of work for mechanics. Sram increases the quality of the shifting processes through flawless adjustment. Combined with the electronic gearbox, which precisely defines the parallelogram of the rear derailleur and allows it to pivot from sprocket to sprocket, there is simply no more misaligned shifting. Because there is also no more variance in the tension of a mechanical cable. T-Type gears simply no longer have any traps that can be stepped into during assembly or adjustment. The Transmission drives take the complexity out of shifting for the user. You really have to thank Sram for that. The complete assembly of the shifting group can be done in less than 30 minutes, even by non-ambitious mechanics. The only novelty compared to the conventional Eagle shifters: The chain can no longer be cut to length while mounting the groupset. The exact chain length must be determined via an app or online calculator. No app is required to pair the shifter and rear derailleur.

Advantages of Sram Transmission (T-Type) shifting systems

• Easy assembly
• No lengthy adjustment needed
• better function, thanks to perfect alignment from the factory
• small part repair possibility

Disadvantages of Sram Transmission drives

• currently very expensive
• only fit frames with UDH derailleur hangers
• slightly heavier than conventional drives
• officially not combinable with other Sram drivetrains

For many, however, the derailleur hanger has not been a disturbing factor for decades, but a deliberate predetermined breaking point between frame and rear derailleur. If a branch gets caught in the drive and bends or tears off the derailleur hanger, you can buy a new derailleur hanger for 10-20 euros and repair the entire bike. The frame and rear derailleur usually survive such confrontations on the trail without damage, if the energy in the derailleur hanger is dissipated. Of course, the question remains: Where does the energy go in such cases, if there is no more derailleur hanger?.

What gets destroyed when the derailleur hanger can no longer break off or bend?

Let’s slap a branch into the derailleur. What will happen? Scenario 1: When you hold the rear derailleur in your hand, you immediately notice the robust construction. There is no unstable wobbling back and forth, as you might remember from old 9-speed rear derailleurs. Instead of thin sheet metal, the parallelogram consists of confidence-inspiring legs. If you look at this rear derailleur, an answer to the question posed above immediately comes to mind: The branch is probably breaking off. Scenario 2: If the branch or obstacle does not break off, the rear derailleur naturally also has the “danger function” like its AXS predecessors. In this case, the rear derailleur recognises a blow from outside as such. The gearbox receives the signal to briefly give way in the direction of the spokes in order to prevent damage. The rear derailleur then returns to its initial position. Scenario 3: If the first two scenarios do not work, would it be conceivable for the frame to take damage? Rather unlikely, as the rear derailleur is not attached to the frame, but primarily to the thru axle. And a 12 millimeter thru axle does not usually bend, even under greater load. Then it is more likely that the rear derailleur will break. Transmission rear derailleurs are not indestructible after all, but they can (for the first time in the history of rear derailleurs) be repaired without specialist knowledge.

How to repair the Sram GX Eagle transmission

The rear derailleur cage with the two pulleys can even be replaced without tools. Of course, the shifting rollers can also be replaced individually. The outer leg of the parallelogram can also be replaced by a layman with only two 2.5 millimetre Allen screws. The gearbox is protected by a plastic cover that can be replaced with just one screw. The part of the rear derailleur that attaches the gearbox to the frame can be replaced with another 5 screws. Sram’s factory service can even replace the rear leg of the parallelogram, or the receptacle for the clutch of the rear derailleur cage. In principle, the rear derailleur was designed like a partially replaceable protective cage around the gearbox. The prices for the spare parts are currently still high; in the future, however, it would even be conceivable for third-party suppliers to place themselves here in order to make repairs possible at low prices.

Prices for spare parts:

• • Rear derailleur cage incl. shifting rollers: 139 €
  • Parallelogram arm (outer): 70 €
  • Plastic cover: 24 €
  • UDH cage: only in Sram service after quotation

Let’s put it through its paces: How does the Sram GX Eagle Transmission shift on the trail

Mount the groupset and get on your bike. You expect great things, but screaming out “wow” takes a little longer. Because the gears shift. It does what it was designed to do. There is a minimal time delay between “pressing the shift lever” and “changing gear”. But that is what we have come to expect from all electronic shifting systems. What is new, however, is the significantly better haptics of the POD controller (this is the name of the T-Type gear lever) compared to the old AXS controller or rocker paddle. Thanks to the clear haptic feedback, you don’t accidentally shift one gear too many or too few. After the first delicate approach, test riders dare to give the new shifting system a good shove. Does the newcomer handle a shift under full load? Yes it does! For decades, I’ve got into the habit of taking pressure off the pedal for a quarter or half turn shortly after pressing the shifter. You can actually save that with the new extremely stiff ensemble.

This is probably the engineers’ response to the increased use of e-bikes. Of course, you can cover a wide range of preferences with the app. Function assignment of the buttons and shifting several gears at the touch of a button. Nice gimmicks. But we were happy with the factory setup. The battery indicated to us after about 30 hours of riding that it would like to be supplied with power again. It did not run out during the test run. Even though the battery runtimes are really good, you somehow feel more independent with a mechanical cable between shifter and derailleur. That makes us a bit sentimental. Otherwise, the big advantage of the transmission system only comes into play when conventional systems start to get on your nerves. The obligatory re-tensioning of the shift cable on a new bike has already been eliminated. And besides, there should be no need to readjust anything. (There are also no mechanical screws to readjust anything. Fine-tuning of the rear derailleur position can still be done electronically in steps of tenth, but this was not necessary on our bike).

Weights of all Sram Eagle Transmission groupsets compared

We took the trouble to weigh each part in the table below. As expected, the cheaper GX Transmission Ensemble turns out to be about 350 and 150 grams heavier, respectively, than the more expensive XX Transmission or XO Transmission groupsets. Somewhat unexpected for the time being is the significant weight increase of 201 grams compared to the mechanical Sram GX Eagle shifting. This is mainly due to the crank with integrated bashguards. If you remove these, you save exactly 80 grams. If you add the weight of a shift cable with continuous outer casing and derailleur hanger and take the bashguard into account, the GX Transmission weighs exactly 40 grams more than its mechanical counterpart. If you want it lighter, you have to dig much deeper into your pocket for the XX or XO or the XX-SL versions of the Transmission groupsets.

Is it worth buying the Sram GX Eagle Transmission? Comparing all transmission prices

In order to have a comparable basis, we will base this article on the RRP offered by Sram or Shimano. Of course we know that the prices will be approx. 15-20 % lower in common online shops just a few days after the presentation. That’s how it always is. Thank you dear market economy for this effect. The GX Transmission is not cheap, but significantly cheaper than its big brothers (XO and XX Transmission). The complete shifting group will soon cost under 1000 €. No bargain, but still OK for a completely new, revolutionary and durable technology. The price for the wear bundle consisting of chain, cassette and chainring is also OK. With a nickel-coated chain and cassette, the durability of the GX T-Type components should be similar to that of the legendary XO-Eagle shift groups. Time will tell. We cannot make any statements on this yet. What is noticeable is that the GX Transmission does not have the bare aluminium spots that the XO Transmission has, for example. Scratches or wear on the crank arm are thus much more visible. On the other hand, the silver finish of the cassette conceals traces of usage much better than the old GX-Eagle cassettes. On the functional level, the only thing worth mentioning is the lack of a Magic Wheel on the GX Transmission compared to the XX or XO versions. The pulleys do not continue to rotate here if you insert a branch into its openings. However, you can retrofit this.

All the standards (interfaces) of the new Sram T-Type groupsets

 

• Free-wheel: XD
• Crank: DUB shaft
• Chainring: Sram Direct Mount 8 Bold (not compatible with old Sram 12 speed chainrings)
• Shift hanger: Frames need a UDH shift hanger
• Battery shift lever: CR 2032 (standard button cell)
• Battery rear derailleur: eTap AXS (compatible with all Sram electronic components)

How does Shimano react to Sram’s transmission offensive?

We mentioned it at the beginning. Sram is currently the undoubted technology leader in MTB shifting. That won’t shake the market power of Shimano, the world’s largest component manufacturer, but it will certainly bother the Japanese in Osaka. In the medium term, something must be done to counter the innovation and speed of development from Schweinfurt. But what? The bicycle manufacturers have agreed on the UDH standard for derailleur hangers. It will be embarrassing if Shimano starts using it, but there is probably no way around it. Shimano also has nothing to show for on the electronic shifter front with decentralised batteries. To set a marker, they would either have to present the 13th sprocket on the cassette (but this is also somehow superfluous for sporty bikers) or show an electronic shifter without batteries. There are patent drawings of electronic derailieurs, that draw their energy from a dynamo in the pulley. But these drawings are still very abstract. It is more likely that Shimano will sooner or later present a direct mount derailleur hanger that is easy to repair at much lower prices than Sram. This is how it has always been done in the past. They let Sram do the pioneering work in order to take back their market share through attractive prices.

Alternatives to shifting systems from Sram and Shimano

Of course, in addition to the market leaders for mountain bike gears, there are also alternatives from smaller suppliers. TRP and Micro Shift try to copy the derailleur systems of the big manufacturers as best as possible. The company Lal Bikes from Canada enters the race with a much more innovative approach. Based on the idea, that a rear derailleur should not be placed so prominently on the frame, the derailleur system was completely rethought here. The rear derailleur cage, which ultimately provides the chain tension, was separated from the rear derailleur and mounted as a separate part near the crank. The rear derailleur parallelogram is well protected in the rear frame triangle. You can currently buy this shifting system in combination with a Nicolai bike. We have already been able to test ride the system and will publish an article on it soon. If you are interested, you can simply subscribe to the newsletter below. At this point, we will only reveal this much. It works, but it also has room for improvement. Why did we nevertheless mention it in this article? Because it shows in an impressive way that innovation in biking knows no bounds. It is quite possible, that gears on mountain bikes will change again in the next 10 years. With e-bikes, more and more manufacturers are starting to combine motors with manual transmissions. There is more movement in the market than you might think.

All bikes with transmission gears

If you’re excited about the new transmission gears, you can buy and retrofit them online. We have the links to the biggest online shops that offer the groupset here.* However, it is more likely that you will get a new bike with transmission gears right away. We are going to list all bikes with the new transmission groupset here, as soon as they are available.