New 105 Di2 12-speed groupset offers electronic shifting at Shimano's lowest price point yet

Shimano 105 Di2 R7150, the brand’s long-awaited third-tier electronic groupset, has finally arrived. The £1,730 / $1,890 / €1,869 groupset brings more affordable electronic shifting to the Shimano road groupset line-up than ever before.

Like Ultegra Di2 R8100 and Dura-Ace Di2 R9200, Shimano's 105 Di2 road bike groupset is semi-wireless and 12-speed. However, unlike those two groupsets, 105 Di2 is only available with disc brakes.

The new groupset is claimed to weigh 2,992g and stands in direct competition with SRAM Rival eTAP AXS.

Here, we take a deep dive into everything you need to know about the new groupset.

We also have a comparison between SRAM Rival eTap AXS and Shimano 105 Di2, alongside a summary of all of the new bikes available with the new groupset.

Plus, you can read the thoughts of BikeRadar’s senior technical writer, Simon von Bromley, on what the release of a third-tier electronic groupset from Shimano means for the future of mechanical groupsets on the road.

Semi-wireless

Like 12-speed Dura-Ace and Ultegra, Shimano 105 Di2 is semi-wireless.

This sees both derailleurs connected to a central battery, with the shifters then connecting wirelessly to the system.

By comparison, SRAM’s eTap groupsets are fully wireless, with both derailleurs controlled by individual batteries.

The rear derailleur houses the brains of the system, and is also where the groupset is charged.

12-speed for everyone

As expected, Shimano's 105 Di2 R7150 groupset is 12-speed. The past two generations of 105 have been 11-speed.

Here, we go over each of the components that make up the Shimano 105 Di2 R7150 drivetrain.

Shimano 105 RD-R7150 rear derailleur

A single long-cage rear derailleur is available in the 105 Di2 family.

The Shimano 105 RD-R7150 Di2 rear derailleur is compatible with cassettes up to 36t.

It is aesthetically similar to both Ultegra and Dura-Ace, but features less complex forming on the knuckles, parallelogram and cage. The appearance is also more matt than the higher-tier groupsets’ shiny finish.

The charging port for the Di2 system is on the rear end of the upper knuckle. This removes the need for a junction box under the stem or in the handlebars, as was the case with previous-generation Di2 groupsets.

Shimano 105 FD-R7150 front derailleur

The new Shimano 105 FD-R7150 front derailleur is slightly larger than the equivalent Dura-Ace or Ultegra front derailleurs.

The upper housing is extended and – unlike Dura-Ace and Ultegra – isn’t offset from the cage, increasing the derailleur’s overall footprint.

It is not specified why the upper housing is larger, though we would speculate it uses different motors and controllers to the higher-tier groupsets. We have asked Shimano for more information.

The derailleur is compatible with chainrings up to 52t in size. The derailleur’s overall capacity (the largest difference in teeth between chainrings) is not specified in the Shimano press pack.

Shimano 105 CS-R7100-12 and CS-HG710-12 12-speed cassettes

A single 11-34t cassette (CS-R7100-12) 12-speed will be available at 105 level.

An additional non-series 11-36t 12-speed cassette (Shimano CS-HG710-12) is also being released alongside the groupset.

The first seven cogs of both cassettes are individual, with the five largest mounted to an alloy spider. All cogs are made from steel.

The cassettes mount using the new 12-speed specific freehub standard, but this is backwards-compatible with 11-speed HG freehubs.

The new cassettes do not feature Hyperglide+ technology.

Initially introduced on Shimano’s mountain bike groupsets, Hyperglide+ sees the cogs on the cassette formed to help guide the chain down (ie, into a harder gear) the cassette.

Hyperglide+ was then ported onto the road last year with Dura-Ace and Ultegra. We’ve found Hyperglide+ to be very effective at smoothing out shifts and dampening down noise in testing.

Dura-Ace and Ultegra-level 11-34t cassettes are officially compatible with the groupset. However, both 11-30 and 11-28t options are not officially compatible.

Unofficially, we expect using either of these cassettes with the RD-R7150 rear derailleur will work, albeit with potentially reduced shifting performance.

The groupset shares the existing CN-M7100 12-speed chain with the brand’s SLX mountain bike groupset.

Shimano FC-R7100 crankset

The new Shimano FC-R7100 crankset looks very similar to the top-tier Dura-Ace R9200 crankset, with a slightly less shiny finish and the same flat outer face on the crank arms.

It is available in 160, 165, 170, 172.5 and 175mm crank length options and, at launch, a single 50-34t gear combination.

A 52-36t option will also be “available at a later date”, according to Shimano.

The crankset has a Q-factor of 148mm and shares the same Hollowtech II construction as most of Shimano’s high-end cranksets. This sees two forged halves of the crankset bonded together to create a lightweight and stiff crankset.

An additional 12-speed compatible non-series crankset is also being launched alongside the groupset. The FC-RS520 crankset features solid crankarms and is designed to work with bikes that use a 135mm rear end.

Most modern road bikes with thru-axles have a 142mm rear end. This affects the bike’s chain line and the FC-RS520 crankset will be offset to accommodate this.

The crankset is available in length options of 160, 165, 170, 172.5 and 175mm, and a single 50-34t gear combination.

Shimano 105 Di2 ST-R7170

The new Shimano 105 Di2 ST-R7170 shifters are identical in layout to 12-speed Ultegra and Dura-Ace.

This includes the new shrouded lever and revised pivot placement, which is said to improve braking performance when riding on the hoods.

The shifters don’t feature the auxiliary hood button seen on the two higher-tier groupsets. They also lose out on the option to fit satellite shifters (or so-called ‘sprint shifters’).

Unlike Dura-Ace and Ultegra, the brakes also don’t feature Servo Wave. Servo Wave makes the relationship between the brake lever and pad non-linear, improving modulation. Servo Wave is also seen on the brand's GRX gravel groupset.

The Shimano 105 Di2 ST-R7170 shifters are claimed to have a battery life of up to three years. They are powered by a pair of CR1632 coin cells in each shifter.

Goodbye to rim brakes

The new Shimano 105 Di2 groupset is only available with disc brakes.

This is the first generation of any Shimano road bike groupset family to be offered without a rim-brake option.

That's not entirely surprising because few modern road bikes are specced with rim brakes, and the vast majority of 105 Di2 sales will be to OEM customers.

While perhaps a little anecdotal, we expect most riders looking to upgrade an older rim-brake bike will be considering either Dura-Ace or Ultegra – both of which are available with rim-brake shifters and matching brakes.

That said, we expect that riders who want to use 105 Di2 drivetrain components in conjunction with rim brakes will be able to use either Dura-Ace or Ultegra 12-speed shifters, but this is yet to be confirmed by Shimano.

Revised disc brakes

The new Shimano 105 BR-R7170 disc-brake calipers adopt the revised layout introduced with Ultegra and Dura-Ace.

This includes the adoption of a new bleed port, which is accessible from the outboard side of the caliper. This makes bleeding the brakes much easier, especially when mounted on the inside of the rear triangle.

The pad-to-rotor clearance is also said to have increased by 10 per cent, reducing the chances of either rubbing in grimy conditions.

The brakes are only available in a flat-mount fitting. Non-series post-mount calipers will also work with the groupset if you’re upgrading an older frameset.

The nominally 105-level non-series SM-RT70 and SM-RT64 rotors carry over from the previous-generation groupset.

Shimano 105 Di2 R7150 groupset weight

Shimano 105 Di2 R7150 is claimed to weigh 2,992g for the complete groupset.

The claimed weights for each component in Shimano’s new 105 Di2 R7150 groupset are as follows:

This is around 276g heavier than an Ultegra R8100 Di2 groupset, which comes in at 2,716g, according to Shimano.

Though it’s hard to make an apples-to-apples comparison, a SRAM Rival eTap AXS groupset is claimed to weigh 3,109g in a broadly similar spec.

Shimano 105 Di2 R7150 groupset price

The suggested retail price for a full Shimano 105 Di2 R7150 groupset is £1,730 / $1,890 / €1,869, depending on spec.

The European pricing relates to the Benelux region specifically, so results may vary slightly locally. Australian pricing is yet to be confirmed by Shimano.

Below is a summary of pricing for key components in the 105 Di2 range in the UK and USA. Pricing for individual products is not currently available in all regions.

Shimano 105 Di2 R7150 groupset availability

Speaking to BikeRadar, Shimano brand manager Geoff Giddings said riders should “expect to see new bike models entering the market during July”, with “component stock… available from the start of September”.

Want to be first in line for a groupset? Probikekit has opened pre-orders for 105 Di2 groupsets to UK buyers for £1,730 with a release date of August 5th 2022. Those in Germany can also pre-order the groupset for the same release date at a cost of €2088.49.

Looking for a new 105 Di2 bike? Check out our guide for the bikes already available with the new groupset.

Shimano WH-RS710-C46-TL and WH-RS710-C32-TL wheels

Though they don’t carry the 105 marque, two new carbon wheelsets round out the launch of Shimano’s new 105 Di2 groupset. This is the first time a carbon wheelset has been offered at a 105 level.

The memorably named Shimano WH-RS710-C46-TL and Shimano WH-RS710-C32-TL wheelsets share the same overall rim profile as the equivalent Dura-Ace and Ultegra wheelsets.

However, both use a heavier carbon layup on the rims to deliver a claimed weight of 1,607g for the C46 and 1,511g for the C32.

Both rims are 21mm wide internally. The 32mm wheels are marketed as a “climbing model” and the 46mm wheels are said to be an “all-round model”.