Shimano has released details of a new 12 speed road group, under the 105 series label, featuring Di2 electronic "semi-wireless" shifting. As with the most recently updated Dura-Ace and Ultegra 12 speed groups, it's electronic shifting, with no wiring connecting the shifters to the rest of the system - but there are still internal wires running between a seatpost battery and the front and rear derailleur.
The new group - called 105 R7100 series - has some cool new features and options, including some that might be interesting for off-road cyclocross and gravel riders. Let's take a look at what I like, and what I don't.
Shimano 105 R7100 pros and cons
Wide-range shifting for the masses
Wider-range cassettes are definitely a big selling point of the 105 R7100 kit. While there have been "hacks" available to allow the use of bigger cassettes like the Wolf Tooth RoadLink DM, it's nice to see an officially supported solution direct from Shimano.
How does 105 R7100 compare to Dura-Ace and Ultegra?
A comparison to Shimano's semi-wireless Di2 Dura-Ace and Ultegra groups is natural, and while 105 12 speed delivers quite a bit of the performance of the more expensive groups, it doesn't have everything. Notable differences:
- 105 R71000 has a weight penalty (expected)
- Each 105 R7100 shifter needs 2 coin batteries instead of 1
- 105 R71000 brifters have no plug/port for satellite shifters
- 105 R71000 lacks the extra buttons on top of the hoods
- Servo Wave, the variable braking leverage ratio found on Dura-Ace and Ultegra 12 speed is missing as well
- The R7100-level chain and cassette don't have Hyperglide+ (but presumably one could use one of the better 12 speed chains as an alternative to the 105 chain, if desired)
You DO get the improved, 10% more clearance between brake pad and rotor, which is great for off-road riding and less expensive frames/forks that have more flex, leading to brake pad drag.
Will your next bike have electronic shifting?
At this point, it isn't a matter of "if", it's a matter of "when" - Shimano's 12 speed Di2 Dura-Ace and Ultegra groups don't even have a mechanical shifting option, and on the SRAM side only low-to-mid end parts have a mechanical shifting option, with the entry point to wireless shifting getter lower every year. So yes - if you ride anything from mid-market all the way up to top end, you can look forward to electronic shifting whether you like it or not.
Shimano 105 R7100 availability
Don't count on being able to buy these new parts anytime soon. Shimano's Dura-Ace R9200 and Ultegra R8100 groups, which were announced at the end of Summer, 2021, are still hard to get. That means it might be quite a while before you can actually by 105 R7100 series Di2 semi-wireless shifting components.
As is typical, you'll likely see complete bikes with 105 R7100 groups available for sale before individual components are available aftermarket for custom builds. If you need a new bike "now", buying a complete bike will be faster than buying a frame and building it yourself.
Should I buy Shimano 105 R7100 Di2 components for my cyclocross or gravel bike?
Maybe. Shimano would certainly suggest their GRX line of components for off-road, drop-bar use, not 105. That being said, the GRX group comes with some downsides that should be considered before you buy:
- GRX is still 11 speed. If you have a fleet of wheels that you're trying to swap between bikes, this is especially problematic. GRX 12 speed is certainly coming, but it doesn't exist as of this writing.
- One of the reasons to choose GRX has been the wide-range cassette options, but the new 105 R7100 group has an 11-36 cassette available, which may be low enough for some riders who'd otherwise want GRX for steep, off-road climbing. Notably, if 105 has a 50/34 crank and 11-36 cassette, many riders will no longer need GRX to get that type of wide-range.
I probably wouldn't invest in a GRX 11 speed bike at this time knowing that better options are sure to be coming soon. It will be interesting to see what pro teams choose for the Fall, 2022 cyclocross season - last year, some stuck with 11 speed Dura-Ace (perhaps due to poor 12 speed availability, or a preference for 11 speed groups due to wider chain/cog spacing) while some athletes went to GRX 11.
With the wide-range 105 R7100 rear derailleur, I suspect we'll also see some mixing and matching opportunities as riders pick and choose their favorite bits from the 3 semi-wireless Di2 groups.