The cycling market has been moving towards disc brakes and electronic groupsets for some time now, but Shimano was lacking an ‘entry-level’ option to rival...errr...Rival. With the new Shimano 105 Di2 now appearing on bikes, we thought we’d take a look at which one is better by digging down into the facts and figures.
It is a little bit tricky to compare these two groupsets on weight as the systems use different chainring and cog sizes, but we've put Sram and Shimano's 'compact' offerings against each other.
SRAM Rival eTap AXS weighs in at a claimed 3,109g with a 46/33T chainset and a 10-33T cassette.
Shimano 105 Di2, meanwhile, with a similar setup, weighs a claimed 2,995g. That is using a 50/34T chainset and an 11-34T cassette. While it is close, Shimano takes this round.
Shimano’s system also uses a larger battery, larger chainrings and still has some wires inside the frame, so the 100g weight saving over Rival, while not exactly massive, is quite impressive.
There is no question that SRAM’s Rival eTap AXS is a cheaper groupset to buy outright than Shimano’s 105 Di2. Rival AXS costs £1,268 for the 2X system without a power meter while 105 Di2 costs £1,730.
But given that most people will be choosing between these groupsets as part of a full bike, the bike prices are the ones that we’re more interested in.
Taking Orro’s Venturi STC as an example, it’s very interesting to find the 105 Di2 bike significantly cheaper at £3,150 than the Rival AXS bike at £3,500.
The difference here represents a good number of accessories, a new pair of shoes or some clothing upgrades to a prospective buyer.
You might prefer one system over the other when it comes to aesthetics, but the good news is that both systems mirror, to a large extent, the more expensive groupsets in their respective ranges.
105 Di2 uses exactly the same lever and hood design as you’ll find on Ultegra and Dura-Ace and this is a shape that we really like.
The Rival AXS levers feature the bigger differences from Force and Red eTap, but again, this boxy design is one that we do like in use.
Down at the chainsets, you’ll find angular designs with both systems, but SRAM’s is the slimmer design, if that is something that you care about.
Cassettes and chains look largely like they should, but when we get to the derailleurs, we do find some differences. As this is where Sram’s batteries are mounted, their front and rear derailleurs look a little bit chunkier to us. They also go for a light grey design whereas Shimano matches the derailleurs to the rest of the groupset with a dark grey.
The front derailleur on the 105 Di2 groupset is, in our eyes, straight out of the previous Ultegra generation parts bin and this larger body is one of the key visual differences from the newest Ultegra and Dura-Ace. But hey, they’ve got to give you some reasons to buy Ultegra.
We'll say it's a draw on the looks front as you'll likely favour one or the other.
Shimano was very keen to tell us that the shifting had become even faster with the latest 12-speed groupsets and thankfully, some of that has trickled down to 105 Di2 with the rear derailleur being fast and accurate. The front derailleur looks as though it has come from the old 11-speed Ultegra Di2 system and the performance supports this theory as, while it is good, the 105 Di2 shifting isn’t as impressive as with the latest Ultegra or Dura-Ace.
Rival AXS works just the same as Force and Red, with the right paddle shifting to a harder gear at the back and the left popping you into an easier one. Press both at the same time and the front derailleur changes. It is a much simpler system to get to grips with, especially for newer riders, but in terms of the quality of the actual shift at the derailleurs, we’d say that Shimano takes a narrow win here.
One of the things that SRAM really did well with the Rival AXS groupset was the brakes. They feel good in your hands and it is easy to control the impressive amounts of power. To be honest, these brakes just work, which is nice.
The braking was one of the biggest improvements that Shimano made with the latest Di2 groupsets with wider pad clearance down at the callipers and Servo Wave technology which made the braking more progressive. While the former is present in the new 105 Di2 groupset, you miss out on Servo Wave and, as a result, the brakes don’t feel quite as nice as Ultegra or Dura-Ace.
Both systems, however, offer brilliant control and a lot of power, so this is a draw.
Both systems feel nice in the hands, but 105 Di2 has seen a significant change from the outgoing model, canting inwards a little to allow for what Shimano says is a more natural hand position.
Shimano uses a lever shape that is a little more flowing. There are few edges here and the additional length makes getting a secure grip over broken surfaces very easy.
Sram's Rival hood design is more angular and has plenty of fans, but we're giving this round to Shimano.
Both systems are 12-speed, but Shimano keeps things relatively traditional by basing 105 Di2 around an 11T smallest cog. The cassette can go all the way up to 36T and, when paired with the compact 34/50T chainrings, gives you a sub 1:1 ratio of 0.94. In inches, that's 25.09. At the other end, you can get 36/52T chainrings for a largest possible gear ratio of 4.73 or 126.26 inches.
Rival AXS, meanwhile, offers a 10-36T cassette and 46/33T chainrings. That gives a lower gear ratio of 0.92 or 24.56. The largest chainrings available with Rival AXS is a 48/35T. Sounds small, but stick it in the 48-10 and you’ll have a ratio of 4.8 or 128.13 inches.
A lot of numbers, but the takeaway is that Rival AXS offers a larger spread of gears.
We’d first say that if you’re buying a bike with one of these groupsets installed, you’re going to be a very happy little cyclist. Both work well and both have their strong points. Both are now easy to connect to your phone and cycling computer. Both weigh about the same, but we think what will separate them is how you’re going to buy either groupset.
If you’re buying as a standalone groupset, the price gulf makes Rival AXS the easy choice. You can have a power meter included and still have money left over compared to what 105 Di2 would cost.
But if Orro’s pricing is anything to go by, the 105 Di2 bike will be the one to go for. The few hundred pounds that you’ll save can go on clothing, accessories or just stay in your pocket.