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This article compares two high-end electronic road bike groupsets: Shimano Dura-Ace Di2 and SRAM RED AXS.
Recently, I tried out SRAM’s RED AXS groupset and compared my experience with Shimano Di2. I’ll share my insights with you in this article.
Setting price aside, both groupsets perform well and are suitable for demanding roadies. However, Shimano Dura-Ace Di2 holds an advantage in the most crucial aspect – shifting.
When considering the price, SRAM RED AXS suddenly appears to be a better deal. So, should you choose it?
I recommend trying both groupsets and forming your own opinion. But, to give you a head start, below, I will discuss deeper key factors such as shifting, braking, ergonomics, and more to help you decide between the two groupsets.
Abbreviations used: FD – front derailleur, RD – rear derailleur
Shimano Dura-Ace Di2 vs. SRAM RED AXS: Summary
The following table summarizes the most important features of these two groupsets.
|Feature||Shimano Dura-Ace Di2||SRAM RED AXS|
|Power meter crankset available||Yes||Yes|
|Satellite shifters compatibility||Yes||Yes|
|Launched||August 2021||February 2019|
Pros and Cons
Let’s now take a look at their pros and cons.
|Shimano Dura-Ace Di2||SRAM RED AXS|
|Pros||• More reliable|
• Better front derailleur shifting
|• Fully wireless
• More user-friendly smartphone app that offers more data
• More affordable
• More reliable power meter
|Cons||• More expensive|
• Less user-friendly mobile app that offers less data
• Less reliable power meter
|• Less reliable
• Worse front derailleur shifting
Shifting is the most critical function of cycling groupsets, and it’s where these two groupsets differ the most.
The first distinction lies in the shifting system. Shimano Di2 features two buttons on each lever. The left lever controls the front derailleur, while the right lever operates the rear derailleur. Dura-Ace Di2 also includes one hidden button on the top of each lever (unlike Shimano 105 Di2).
You might also be interested in this comparison of Shimano Dura-Ace vs. Ultegra vs. 105 Di2.
SRAM takes a different approach to shifting, making it more straightforward. Each shifter has only one button. To shift the front derailleur, you press both buttons simultaneously. Shifting the rear gears involves pressing either the left or right button.
Each groupset has its fans. I suggest trying both to see which one suits you better. Personally, I’m used to Shimano, but I find SRAM to be very intuitive.
Let’s turn our attention to shifting speed for a moment. Both groupsets have comparable performance in this regard.
However, SRAM front derailleur shifting proved to be less reliable. I felt it was not as accurate, smooth, and reliable as Shimano.
A significant difference between Dura-Ace Di2 and RED AXS lies in their wiring: Dura-Ace Di2 is semi-wireless, while RED AXS is entirely wireless.
For Dura-Ace, cables run from the hidden battery (inside the seatpost) to the front and rear derailleurs. No cables connect the shift levers to the battery because they have a CR1632 battery inside.
On the other hand, SRAM’s system is fully wireless. The shifters and the front and rear derailleurs have their own batteries. The battery between derailleurs is even swappable and compatible with other SRAM road groupsets like Force or Rival.
The wireless groupset provides an advantage, particularly for those who want to build their own bike, as installation becomes easier.
We’ve been used to “standard” gears on road bikes for a long time. But as the picture below shows, SRAM has changed the game with their X-range gearing.
In fact, it was designed so you don’t need to shift the front chainring as often. SRAM achieved this by making it smaller but, at the same time, increasing the gear range of the cassette.
To give you a complete overview, here’s a table displaying the available chainring and cassette options:
|SRAM (X-Range)||Shimano (traditional, road)|
|Chainrings||50/37, 48/35, 46/33T||53/39, 52/36, 50/34T|
|Cassettes||10-26, 10-28, 10-33, 10-36T||11-23, 11-25, 11-28, 11-30, 11-32, 11-34, 11-36T|
The Shimano Dura-Ace Di2 (R9250) weighs approximately 2438g. Interestingly, despite being wireless, the SRAM RED groupset is a bit heavier (around 2478g).
I don’t believe the weight difference should be a deciding factor when choosing which groupset to purchase – an average banana weighs twice as much.
The overall design impacts functionality and aerodynamics, but I’ll leave that discussion to engineers. I’ll focus solely on appearance.
Personally, I’m more attracted to RED. But Dura-Ace looks good too, but I think the previous generations were sleeker.
Which one do you prefer?
Winner: It’s a draw
Ergonomics is crucial to me. Having shifters that fit comfortably in my hands during long rides helps prevent discomfort (and potential blisters) and enhances the overall riding experience.
SRAM RED has pretty bulky levers. Although I have pretty large hands, I don’t like them (furthermore, they are not aero). Dura-Ace is the clear winner.
The braking experience is quite similar for both groupsets, unlike mountain bike groupsets, where the braking effect varies slightly.
Unfortunately, I haven’t had the chance to test both sets side by side, nor have I found a comprehensive braking test.
However, you can expect similar braking performance based on the results of the SRAM Rival AXS and Shimano 105 Di2 test.
Winner: It’s a draw
Satellite shifters are valuable accessories for climbers or time trialists, as they eliminate the need to move your hand to change gears. Unlike Shimano 105 Di2, the Shimano Dura-Ace Di2 supports them because it does have an accessory port.
SRAM RED also has this port (unlike Force and Rival), so you can easily connect satellite shifters to it.
Both groupsets have Bluetooth and smartphone connectivity. However, SRAM’s mobile app is more user-friendly and delivers more information than Shimano’s.
As a result, if you’re interested in tracking the miles ridden on each gear or want to quickly reconfigure the buttons, SRAM is the better choice.
Both groupsets are also available with a power meter. But it’s worth noting that Shimano power meters don’t have the best reputation, unlike Quarq power meters found on SRAM groupsets.
For this reason, I recommend using one of these reliable power meters with the Shimano groupset.
In terms of cost, SRAM holds an advantage. The Shimano Dura-Ace R9250 is priced at an incredible $4500 (excluding a power meter). You can buy a pretty good road bike at this price range.
Meanwhile, the SRAM RED AXS has maintained decent affordability, costing you only about $2400.
This makes it a more appealing option than the Dura-Ace.
Total Score: Shimano (3), SRAM (4), It’s a draw (2)
Shimano Dura-Ace Di2 vs. SRAM RED AXS: FAQ
Considering the significant price difference, SRAM RED AXS offers better value.
However, if you don’t want to compromise, I recommend going for Shimano Dura-Ace Di2. It outperforms RED in the most crucial aspect – shifting (especially the front derailleur).
Which of these two groupsets appeals to you more? Do you prefer Shimano or SRAM? Let me know in the comments.