Shimano To Release First 105-Series Di2 Components
For Shimano lovers, electronic shifting used to mean a pretty substantial investment. Today Shimano announces a budget, semi-wireless 12-speed Di2 system. But will it work for triathletes?
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Though triathletes haven’t traditionally been as wrapped up in shifting components as roadies, it’s still big news when Shimano announces their first 105-level electronic shifting package, effectively bringing their entire range up to 12-speed at the same time. Today Shimano announced a full 105 Di2 12-speed groupset—with cassette, derailleurs, chain, crankset, disc calipers, rotors, and road levers. We’ll break down the prices, weight, and how triathletes can (and can’t) get some inexpensive Shimano electronic 12-speed on their aero rides.
Shimano 12-Speed 105 Di2: What’s New
When comparing the new R7100 series of 105 Di2 to the Ultegra R8100 set released about a year ago, you’re basically looking at slightly cheaper, slightly heavier apples to apples. See the price and weight differences below. But when looking at the new Di2 105 groupset compared to the last iteration of Shimano 105, there are some very striking differences—as this is the first electronic 105 series to be released by Shimano, in any speed.
The previous version of Shimano 105, the R7000 series, was 11 speeds, hydraulic- or rim-brake compatible, and mechanical. The new version does not have a rim brake option, and is semi-wireless with no mechanical option available as of press. For road setups, the new brake levers/shifters transmit to the front and rear derailleur—negating the need for wires to come from the shifters/brakes to the derailleurs themselves. The term “semi-wireless” is used because both the front and rear derailleur still run wires to a central battery—usually housed in the seatpost. This is different than SRAM’s fully wireless system that uses batteries mounted on both the front and rear derailleurs. Shimano has said this central battery drives more uniform power—resulting in a more consistent connection and crisper shifts. On all versions of the new 12-speed groupsets, the charging port is centrally located on the rear derailleur.
Users of the new R7100 series can also make shifting adjustments, customize shifting, and more with the compatible wireless Shimano E-TUBE app.
Shimano 12-Speed 105 Di2: The Parts
Here is the pricing, weight, and comparisons between Di2 105 R7100 series and Di2 Ultegra R8100 groupset where available.
| Part Number | Price | Weight | Price Difference from Ultegra Di1 | Weight Difference from Ultegra Di2 | |
| Drivetrain | |||||
| 105 Cranksets with Chainrings (50-34T available, 52-36T to come) | FC-R7100 | $180 | 765.6g | -$135 | +54g |
| 105 Cassette (11-34) | CS-R7100 | $66 | 361g | -$46 | +64g |
| Cassette (11-36) | CS-HG-710-12 | $88 | -$24 | N/A | |
| 105 Di2 Front Derailleur | FD-R7150 | $153 | 142g | -$107 | +26g |
| 105 Di2 Rear Derailleur | RD-R7150 | $280 | 302g | -$130 | +38g |
| 12-Speed Chain | CN-M7100 | $33 | 252g | Same | Same |
| Brakes | |||||
| Disc Brake Rotor (160mm) - Each | SM-RT70 | $46 | 133g | -$10 | +79g |
| 105 Hydraulic Disc Brake Set (Front Caliper and Left Lever) | J-Kit Brake Set | $405 | 834g | -$132 | N/A |
| 105 Hydraulic Disc Brake Set (Rear Caliper and Right Lever) | J-Kit Brake Set | $40 | 834g | -$132 | N/A |
| Wheels | |||||
| 105 C32 Tubeless Disc Brake Wheelset | WH-RS710-C32-TL | $1050 | 1,504g | New | New |
| 105 C46 Tubeless Disc Brake Wheelset | WH-RS710-C46-TL | $1050 | 1,612g | New | |
| Di2 Parts | |||||
| Di2 Battery | BT-DN300 | $185 | 53g | Same | Same |
| Di2 Charger | EW-EC399 | $50 | N/A | Same | Same |
As you can see from the above chart, the front and rear derailleur are both places where you can save a substantial amount of cash without adding a ton of weight. In fact, a roughly $2,000 complete 105 build is around 20% cheaper, on average, than what you can find for an Ultegra Di2 build, and you’re only adding around 200-300 grams—by our rough calculations. This is good news for Shimano adherents who want 12-speed, but don’t want to spend on Ultegra-level components.
Shimano 12-Speed 105 Di2: What About Tri?
Sadly, much like the announcement behind the new Ultegra and Dura-Ace 12-speed groupsets, tri has (kind of) been left behind again. The latest 105 groupset is similarly semi-wireless in that the road brake levers/shifters transmit shifting information to the front and rear derailleur wirelessly, but there is still a central battery wired to each. As Shimano has still not released a wireless bar-end shifter or base-bar shifter/brake, triathletes who want electronic 12-speed will need to use an inexpensive EW-AD305 step-down adapter that runs from the old electronic shifting bar-end and brake-lever switches. The adapter also requires a fully wired setup, so no super-sleek front ends for Shimano fans just yet.
Shimano 12-Speed 105 Di2: The Good With The Bad
For triathletes, today’s announcement is bittersweet, as it brings 12-speed electronic shifting into a more affordable range—less than most SRAM Force eTap AXS packages—but it still leaves SRAM as the only viable option for wireless (or even semi-wireless) shifting in tri. If you’ve been waiting to upgrade to 12-speed from electronic 11-speed and don’t mind buying an extra adaptor, this should be a no brainer. If you’re thinking about going from mechanical to electronic, this is also a good option—though it’s still wired. Look for the R7100 Di2 105 Series of 12-speed components to be available from Shimano later this summer.