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Shimano takes aim at SRAM's popular Rival eTap AXS groupset.

If you’ve been paying close attention to the world of drivetrain components, then you knew it was only a matter of time before Shimano's 105 went electric to compete with competitor SRAM's popular Rival ASX eTap group. That day has finally arrived, with Shimano unveiling its new 105 Di2 groupset. Featuring lots of trickle-down tech from its Dura-Ace and Ultegra groups launched last year, Shimano also included a few new bits aimed at making the groupset more user-friendly.

Unfortunately, media samples of the new groupset won't be available until “late summer 2022,” and Shimano doesn’t expect new groupsets to be available for purchase in the US until then either. So, what we know about the new groupset is based on information provided by Shimano, our previous experience with their groups, chats with some product insiders, and looking long and hard at photos of the new parts.

According to Shimano, the new 105 Di2 groupset (without a bottom bracket) weighs 3,068 grams and the pricing of the group is currently slated to be $1,886. These numbers slot the new groupset at a bit pricier than SRAM’s Rival eTap AXS, but with the new 105 being a bit lighter. The SRAM group costs $466 less and weighs 135 grams more.

Shimano’s 105 Di2 is just 89 grams heavier but also $844 cheaper!

A potentially more exciting comparison for riders (and Shimano) is the new 105 Di2 vs. SRAM’s mid-tier Force eTap AXS groupset. Currently, Force eTap AXS is priced at $2,730 and weighs 2,979 grams. Shimano’s 105 Di2 is just 89 grams heavier but also $844 cheaper!

So, while SRAM’s Rival eTap AXS groupset is still the most affordable option for riders looking for the 12-speed, electronic shifting experience, 105 Di2 will absolutely be in that conversation. With 105’s competitive weight and considerable price savings, it might also push potential SRAM Force customers to the new Shimano group.

That last part is a “might” because riders seeking SRAM Force will probably be more tempted by Shimano’s Ultegra 8100 Di2 groupset, which retails for $2,570 and weighs 2707 grams—making it $160 cheaper and 272 grams lighter than SRAM Force. Or, to put it another way, 105 Di2 is $684 cheaper and 361 grams heavier than Ultegra.

Like the latest Dura-Ace and Ultegra groups, 105 Di2 gets a 12th gear, semi-wireless layout, and updated ergonomics. The brakes get an update for quieter running along with 10% more pad clearance and an easier bleeding process (that does not require removing the caliper from the frame). 105 Di2 also offers an expanded gear range with a new 11-36T cassette that, combined with a 50/34T crankset, gives riders a lower than 1:1 low gear.

The new low gear makes 105 more competitive in gear range with SRAM’s Rival eTap AXS. However, the SRAM groupset is still leads with it’s 46/33T crankset option and 10-36T cassette. Other gearing options for 105 Di2 include a 52/36T crankset and an 11-34T cassette.

According to Shimano, the new 11-36T cassette will not be compatible with Dura-Ace or Ultegra rear derailleurs, which max out at 34T capacity. But this is one of the first things I’ll test when I get my hands on the new group, as I can’t be the only Dura-Ace or Ultegra rider who would want the extra range.

Shimano sticks with the same internal DN300 battery as Dura-Ace and Ultegra for the new 105 Di2 group so riders can expect similar ride time between charging. Based on my experience with the new Dura-Ace group, riders should expect to charge somewhere between 40 and 50 hours of ride time from a full charge.

Charging is a straightforward process since 105 Di2 shares the same charging port and cable as Ultegra and Dura-Ace. In one sense charging Shimano is a bit easier than charging SRAM AXS. There is only one main battery, but it does require you to plug your bike into the wall as the charging port is located on the rear derailleur. This can be a bit of a problem if you store your bikes somewhere without easy access to an outlet. In that sense, SRAM can be a bit easier as you can take the batteries off the bike to charge elsewhere, just with the added hassle of needing to charge multiple batteries. In the end, this one is a bit of a toss-up for me.

Because Dura-Ace, Ultegra, and the new 105 Di2 share the same battery they also use the same SD300 wire, meaning that all of the electronic components from the various groups play nicely together. So, riders seeking a Shimano approved way to run the 11-36T cassette can eventually plug a 105 rear derailleur into their Ultegra or Dura-Ace groupsets.

Unlike Ultegra, which shares every feature of Dura-Ace with only some added weight, not everything has trickled down from the higher-end groups to 105 Di2. First, 105 shifters can not be set up with accessory shift buttons. Similarly, there is no third button on the top of the shifter body for 105. In its place is a battery compartment that houses two CR2032 batteries. Shimano says that it prioritized increased battery life, up to three years compared to 12 to 18 months on Dura-Ace and Ultegra, over having the extra button.

Two less visible omissions from 105 Di2 that made the latest Dura-Ace and Ultegra so dang good—Hyperglid+ and Servo Wave—are not used on the new groupset. If you are unfamiliar, Hyperglide+ is a tooth shaping introduced on Shimano’s XTR mountain bike groupsets and brought to the road with Dura-Ace and Ultegra. The unique tooth shaping helps move the chain more quickly and quietly during shifts.

Servo Wave is another bit of Shimano tech from its mountain bike components. The Servo Wave lever pivot mechanism alters the amount of fluid the brake lever moves through its stroke. The idea is that you want to move more fluid at the start of the stroke for less free lever travel before the pads make contact with the rotor for a more immediate response. Then move less fluid towards the end of the stroke to increase modulation and give riders more precise braking control.

I raved about these tech bits in my review of the new Dura-Ace groupset. Without having used the new 105 Di2 I can only speculate how leaving these two bits of tech out will affect performance. Shift speeds are claimed to be as fast as 11-speed Dura-Ace and Ultegra Di2 (which is very fast) but slightly slower than 12-speed Dura-Ace and Ultegra. With no Servo Wave, it is a safe bet to expect a bit less modulation at the levers than 12-speed Dura-Ace and Ultegra brake systems.

Like with the latest Dura-Ace and Ultegra groups, riders will need to use the E-Tube App on their smartphones to make adjustments, such as setting limits for the derailleurs and adjusting trim. The app can also be used to customize things like shift speed, the number of shifts executed when holding down a button, and turning Synchronized or Semi-Synchro functionalities.

Shimano continues the 105 theme of trickle-down technology by launching two sets of its most affordable carbon road wheels. Both the C32 (1,504g) and the C46(1,612g) will retail for $1,050 and feature a 21mm internal rim width and have tubeless-ready hooked rims. As the name suggests, the C32 has a 32mm rim height and is meant to be a lightweight wheelset for climbing and accelerating fast. The C46 has a 46mm rim height and is designed as an all-around set of wheels. Unlike the newest Dura-Ace and Ultegra wheels (which are 12-speed only), these non-series wheels are both 11 and 12-speed compatible.

Rim brake enthusiasts will be disappointed as there is no version of the new 105 Di2 planned for them “at this time”. Though this hardly seems like a surprise given that it’s been almost a year since Dura-Ace launched with a rim brake option and I have still yet to see a single new bike with that set up.

If you’re wondering about the future of mechanical shifting, you’re not alone. It was the first question I posed to Shimano when they sent us the information for 105 Di2. Right now it seems that Shimano wants to leave all of us in suspense. There is currently nothing firm regarding what will happen with 105 mechanical. For the time being, the 11-speed mechanical 105 will continue to be supported. But that’s literally all the information Shimano would give me. If I had to speculate, I would say they are being intentionally vague here and some sort of update to mechanical 105 is hopefully in our future.

With Dura-Ace, Ultegra, and now 105 Di2 all moving to 12-speed, semi-wireless formats, Shimano’s GRX groupset is starting to feel dated. Current GRX still works beautifully, but things like larger cassettes for 2x drivetrains and better brakes with more pad clearance would certainly make it better. Right now GRX Di2 is in a weird limbo of being Shimano’s lone 11-speed, electronic drop bar groupset.

The future of Di2 mountain bike drivetrains has been up in the air now for the past few years. Technically, Shimano still offers Di2 options for its XTR and XT platforms, but they are fully wired and only available in 11-speed configurations. These groups are also eight years old now (we first reported on XTR M9050 Di2 in May 2014) and Shimano’s newer 12-speed mountain bike drivetrains are only available as mechanical groupsets. Will we see Shimano’s developments in semi-wireless shifting make the jump over to knobby tires? This remains completely unknown at this time. But with SRAM AXS Eagle 1x groups starting to dominate the trails on mountain bikes and mullet-drivetrain gravel bikes, we hope Shimano has something cooking for those who like to ride on dirt.

Ride impressions! We have no idea how the new 105 Di2 actually performs on the bike. It’s all good to pour over tech sheets, compare weights, and dig into gear charts, but until we actually get some road time with the new parts it will be impossible to say. The big question remains: Will the new 105 Di2 be as good as it sounds and how does it compare to its main competitors Rival and Force eTap AXS? Look for the full review once the parts are in our hands.