Launched: SHIMANO 12-speed Mechanical Shifting on new 105 groupset

Shimano 105 Mechanical 12-speedSHIMANO 12-speed Mechanical Shifting on new 105 groupset

With the unveiling of the SHIMANO 105 R7100 Mechanical 12-speed groupset, Shimano offers cyclists a combination of reliability, ease of maintenance, and affordability.

This latest addition to the SHIMANO range is not only lightweight but also emphasizes Premium Mechanical Shifting. This ensures that riders have a ‘natural’ cycling experience without the concern of battery longevity. Furthermore, they can benefit from the advanced features of a high-quality 12-speed groupset.

The SHIMANO 105 Mechanical 12-speed is equipped with the RD-R7100 rear derailleur which has a streamlined profile combined that has single-tension construction, and quiet performance. Conversely, the FD-R7100 front derailleur employs toggle-link construction, ensuring that riders have consistent and trouble-free shifting up or down.

With 12-speed, the SHIMANO 105 R7100 Mechanical groupset provides good gear ratios over a wide range including 11-34T and 11-36T cassette options. Additionally, the FC-R7100 HOLLOWTECH II 12-speed cranksets offer 50-34T and 52-36T chainring selections.

Opting for the 50-34T chainrings with an 11-36T cassette allows cyclists to tackle steep terrains while maintaining an efficient cadence.

Shimano claims that the ST-R7120 Shift/Brake levers deliver a smooth shifting experience combined with comfort and control.

Braking efficiency is claimed to be improved with the new SHIMANO 105 BR-7170 callipers. These now provide an additional 10% clearance with the brake rotor, resulting in minimized friction and a more silent operation. The entire system is crafted for durability and ease of maintenance, with specific innovations to streamline the brake bleeding process.

Each element of the Shimano 105 Mechanical is specifically designed for efficient and rapid performance.

So What?

I can’t see any point in completely upgrading from 11-speed to 12-speed. At a minimum, you will need new cassettes for all your old wheels plus an entirely new groupset…mixing and matching with 11speed components, even chainrings, will be tricky.

Thus 12-speed comes into play if you only have one bike and are changing the bike, in which case a 12-speed setup must be more future-proofed than 11. Added to that, Shimano 105 is the last of Shimano’s 12-speed performance road ranges to hit the market. Hopefully, many of the component availability issues that hit Dura-Ace and Ultegra are things of the past.

As an aspiring cyclist, 105 is a good call. Ultegra is better and lighter but going all the way to a premium Dura Ace setup is almost certainly not worth it for most of us.

Perhaps more importantly my personal recommendation is to consider Di2 or electronic shifting. It is better and once you get used to it you’ll never want to go back. You should also consider that many cheap parts from less than official sources are not genuine and may well not last as long or shift as well. One of the points of going for top-branded components is that, quite simply, they work better – for example, if you examine a rear cog on a cassette you will see they have very strange shapes at the smallest levels of detail, this aids faster and more accurate shifting.

A few years back I decided to stick with rim brakes for several years mainly because I didn’t want the hassle and noise of disk brakes catching and squealing. So what attracts me to mechanical 105 is the greater clearance between the brake pads and disc. That should help and might have been a factor for me going disc were it available a few years ago.


Shimano 105 Mechanical Part Numbers & Weights

FC-R7100 Crank

  • 2 x 12-speed
  • Chainring combinations: 50-34T and 52-36T
  • Crankarm length: 160mm, 165mm, 170mm, 172.5mm, 175mm
  • Weight: 765.6g (50-34T)

CS-R7101-12 Cassette

  • HYPERGLIDE 12-speed
  • 11-tooth small cog for optimal efficiency
  • Compatible with 11-speed freehub bodies
  • Cassette combinations: 11-34T and 11-36T (CS-HG710-12)
  • Weight: 361g (11-34T)

FD-R7100 Front Derailleur

  • Brazed-on
  • Fast, precise front shifting
  • Weight: 96g

RD-7100 Rear Derailleur

  • Direct mount attachment
  • Super low profile, single-tension construction
  • Weight: 249g

ST-R7120 Hydraulic Disc Brake Set (Shifters and Levers)

  • Dual control levers
  • New blade shape gives a shorter lever access curve
  • Refined ergonomics and shaping create a new lever position
  • Weight: 612g / pair

SM-RT70 Disc Brake Rotors

  • Disc Brake Rotors (160 / 140mm)
  • Weight: 285.6g

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2 thoughts on “Launched: SHIMANO 12-speed Mechanical Shifting on new 105 groupset

  1. Mixing and matching components works find in the Shimano-universe. Unfortunately, however, you need to rely on third-party knowledge in order to do so well.

    I have Tiagra 4700 shifters connected to Deore 6100 brakes (all the single piston designs have the same hydraulic ratio, 6100 has the bleed ports in the improved location).

    Those 4700 shifters are also connected to a R7000 FR. (The toggle link front derailleurs are on the same cable pull as the “long arm” 4700 which is the cable pull introduced with 5800 and 6800).

    Those 4700 shifters are also connected to a GRX-600-seried RD. (4700, while 10 speed, is on the same cable pull as 11 speed (and likely 12 speed, that’s yet to be measured that I’ve seen)).

    All running on a 105 crankset which was old before 10 speed was even a thing, and Deore XT hubs.

    It all works flawlessly, there’s no fudge factor in the compatibility, it’s just that jerky Shimano doesn’t publish all the relevant specs.

    1. you are to be commended for the research you must have done to make sure it was all going to work!
      as you say, it’s not easy to find out the true compatabilities of various shimano compoennts from different group sets. and eve when things can be mechanically compatible they might be a different hue/colour or not quite look as good when mixed (eg rings and crank).

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