The Shimano 105 Di2 R7150, the brand’s long-awaited third-level electronic kit, has finally arrived. The £ 1,730 / $ 1,890 / € 1,869 group kit brings more affordable electronic switching to the Shimano range of road groups than ever before.
Like the Ultegra R8100 and Dura-Ace R9200, Shimano’s 105 Di2 road bike group is semi-wireless and 12-speed. However, unlike these two kits, the 105 Di2 is only available with disc brakes.
The new group kit is said to weigh 2992 grams and is in direct competition with the SRAM Rival eTAP AXS.
Here we dive deep into everything you need to know about the new group set.
We also have a comparison between the SRAM Rival eTap AXS and the Shimano 105 Di2, along with a summary of all the new bikes available with the new set of groups.
You can also read the thoughts of BikeRadar’s senior technical author, Simon von Bromley, on what it means to launch Shimano’s third-level electronic groups for the future of mechanical road groups.
Here are the five key things you need to know about Shimano’s new 105 Di2 kit:
- Like the Dura-Ace and Ultegra, the 105 Di2 is semi-wireless and 12-speed
- It is claimed that a complete set of the group weighs about 2992 g, depending on the specification
- The full Shimano 105 Di2 kit will sell for around £ 1,730 / $ 1,890 / € 1,869
- For the first time, Shimano will offer a nominal 105-speed carbon wheels
- 105 Di2 will only be available with disc brakes – RIP brakes!
Semi-wireless
Like the Ultegra and Dura-Ace, the group kit is semi-wireless. Shimano
Like the 12-speed Dura-Ace and Ultegra, the Shimano 105 Di2 is semi-wireless.
This sees both derailleurs connected to a central battery, and then the switches are connected wirelessly to the system.
By comparison, SRAM eTap groups are completely wireless, with both derailleurs powered by separate batteries.
The rear derailleur houses the brains of the system and is also the place where the group kit is loaded.
12 speeds for each
As expected, Shimano went 12-speed with 105. Fairlight
As expected, Shimano’s 105 Di2 R7150 group has 12 speeds. The last two generations of 105 were 11-speed.
Here we look at each of the components that make up the drive of the Shimano 105 Di2 R7150.
Shimano 105 RD-R7150 rear derailleur
A single rear derailleur with a long cage (SGS in the Shimano nomenclature) is available. Shimano
The 105 Di2 family offers a rear derailleur with a long cage.
The rear derailleur Shimano 105 RD-R7150 Di2 is compatible with cartridges up to 36t.
Aesthetically, it is similar to Ultegra and Dura-Ace, but has a less complex shape of the knuckles, the parallelogram and the cage. The appearance is also more matte than the glossy finish of the higher level groups.
The charging port of the Di2 system is at the rear end of the upper bone. This eliminates the need for a junction box under the stem or in the handlebars, as was the case with the previous generation Di2 groups.
Front derailleur Shimano 105 FD-R7150
The new front derailleur is slightly larger than that of the Ultegra or Dura-Ace. Fairlight
The new Shimano 105 FD-R7150 front derailleur is slightly larger than the equivalent Dura-Ace or Ultegra front derailleurs.
The upper body is elongated and – unlike the Dura-Ace and Ultegra – is not displaced by the cage, which increases the overall footprint of the derailleur.
It is not specified why the upper body is larger, although we would speculate that it uses different motors and controllers compared to the higher level groups. We asked Shimano for more information.
The derailleur is compatible with chain rings up to 52t in size. The total capacity of the derailleur (the largest difference in teeth between the chain rings) is not specified in the Shimano press package.
12-speed Shimano 105 CS-R7100-12 and CS-HG710-12 cartridges
A cartridge with 105 stamps is available. Shimano
A single 11-34t cartridge (CS-R7100-12) with 12 speeds will be available at level 105.
An optional 11-36t 12-speed cassette (Shimano CS-HG710-12) is also available with the group kit.
The first seven teeth of the two cassettes are individual, with the five largest being mounted on an alloy spider. All teeth are made of steel.
The cartridges are mounted using the new 12-stage specific free hub standard, but this is backward compatible with the 11-stage HG freehub.
A second 11-36t cartridge is also available. Shimano
The new cartridges do not have Hyperglide + technology.
Originally introduced in Shimano’s mountain bike groups, the Hyperglide + sees cassette tines formed to help the chain bend down (ie towards a harder gear) on the cassette.
Hyperglide + was transferred to the road last year with Dura-Ace and Ultegra. We found that Hyperglide + is very effective in smoothing shifts and suppressing noise during testing.
The 11-34t Dura-Ace and Ultegra cartridges are officially compatible with the bands. However, both 11-30 and 11-28t options are not officially compatible.
The group kit shares the M7100 chain as used in the brand’s SLX mountain bike group. Shimano
Unofficially, we expect the use of one of these RD-R7150 rear derailleur cartridges to work, albeit with potentially reduced switching performance.
The group kit shares the existing 12-speed CN-M7100 chain with the brand’s SLX mountain bike group.
Shimano FC-R7100 elbow
One gear option will be available at startup. Shimano
The new Shimano FC-R7100 crank looks very similar to the highest crank Dura-Ace R9200, with a slightly less glossy finish and the same flat outer surface of the crank.
Available in crank length options of 160, 165, 170, 172.5 and 175 mm and a combination of 50-34t speeds on the market.
The 52-36t option will also be “available at a later date,” according to Shimano.
The knee kit has a Q-factor of 148 mm and shares the same Hollowtech II construction as most high-end knee kits from Shimano. This sees two forged halves of the crank connected together to create a light and hard crank.
An additional non-standard crank is also available, designed for 135 mm rear bikes. Shimano
An additional 12-speed non-standard elbow is also available with the group kit. The crank FC-RS520 has solid cranks and is designed to work with bicycles that use 135 mm rear end.
Most modern road bikes with running axles have a 142 mm rear end. This affects the engine chain line and the FC-RS520 crank will be shifted to accommodate this.
The elbow kit is available in length options of 160, 165, 170, 172.5 and 175 mm and a combination of speeds 50-34t.
Shimano 105 Di2 ST-R7170
The 105 R7170 switch is almost indistinguishable in shape from Ultegra and Dura-Ace. Shimano
The new Shimano 105 Di2 ST-R7170 switches are identical in layout to the 12-speed Ultegra and Dura-Ace.
This includes the new covered lever and the redesigned hinge arrangement, which is said to improve braking performance when driving the hoods.
The switches do not have the additional cover button, which is visible on both groups of a higher level. They also lose the ability to install satellite switches (or so-called “sprint switches”).
Unlike Dura-Ace and Ultegra, the brakes also do not have Servo Wave. Servo Wave makes the connection between the brake lever and the pad non-linear, improving modulation. Servo Wave is also seen in the gravel group of the GRX brand.
The Shimano 105 Di2 ST-R7170 switches are said to have a battery life of up to three years. They are powered by a pair of CR1632 coin cells in each switch.
Goodbye to the brake rims
Unlike the Ultegra R8100 and Dura-Ace R9200, the 105 Di2 R7150 will not be available with a rim brake option. Shimano
The new Shimano 105 Di2 is only available with disc brakes.
This is the first generation of all groups of Shimano road bike kits that are available without a rim option.
This is not entirely surprising, because few modern road bikes are equipped with wheels, and most of the sales of the 105 Di2 will be to OEM customers.
Although perhaps a bit anecdotal, we expect most riders who want to upgrade an older motorcycle with a rim to consider either a Dura-Ace or an Ultegra – both of which come with rim switches and suitable brakes.
However, we expect that riders who want to use 105 Di2 drive components in conjunction with the wheels will be able to use either Dura-Ace or Ultegra 12-speed switches, but this has yet to be confirmed by Shimano.
Revised disc brakes
The new disc brake calipers are very similar in shape to Ultegra and Dura-Ace. Shimano
The new Shimano 105 BR-R7170 disc brake calipers adopt the revised layout introduced with Ultegra and Dura-Ace.
This includes accepting a new vent hole that is accessible from the outside of the caliper. This makes venting the brakes much easier, especially when mounted on the inside of the rear triangle.
The brakes can now be deaerated on the side of the device. Shimano
The clearance between the pad and the rotor is also said to have increased by 10 percent, reducing the chances of friction in dirty conditions.
The brakes are only available in flat mounting. Non-standard devices after installation will also work with the group kit if you upgrade an older set of frames.
The nominal 105-stage non-series rotors SM-RT70 and SM-RT64 have been transferred from the group of the previous generation.
Shimano 105 Di2 R7150 weight
The complete set is said to weigh 2992 grams. Shimano
The Shimano 105 Di2 R7150 is said to weigh 2992 grams for the complete set.
The stated weights for each component in the new Shimano 105 Di2 R7150 kit are as follows:
That’s about 276 grams heavier than the Ultegra R8100 Di2, which comes in at 2,716 grams, according to Shimano.
Although it is difficult to make a comparison between apples and apples, it is claimed that the SRAM Rival eTap AXS weighs 3109 grams in an almost similar specification.
Shimano 105 Di2 R7150 groupset price
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