Test of the Shimano 105 Di2 12V R7150 group, this wrongly unloved

Presentation

I am not going to give an exhaustive presentation of the technical side of this group, for that, I invite you to read/reread the article “SHIMANO 105 Di2: 12 speeds and wireless transmission for everyone“.

Aesthetically, the 105 Di2 R7150 groupset is very close to the Ultegra and Dura-Ace Di2. The glossy finish is even closer to Dura-Ace than Ultegra which is matte.

Crankset, rear derailleur, brake levers and calipers are aesthetically very close to these high-end versions. In the end, only the front derailleur is more massive than the big brothers, resembling the old Dura-Ace or Ultegra 11-speed derailleurs.

Shimano has undoubtedly made the decision to recycle proven motors, perhaps a little slower than the new Ultegra or Dura-Ace versions, but which allow them to maintain a lower price.

For everything else, we are entitled to rather fine components, whether it is the rear derailleur or even the brake levers which take up the ergonomics of the new Di2 generation. We just have to ignore the buttons located at the top of the cookers which allow you to change speeds or, for example, to control a counter. We also lose the possibility of connecting additional sprinter type buttons.

As “compensation”, Shimano has equipped these levers with two CR1632 batteries instead of one, which actually increases their lifespan, from 2 to 4 years!

Rather compact levers and above all, with good ergonomics. Apart from the different materials, it is difficult to see any difference with the Ultegra models. The connection between levers and derailleurs is always wireless. Only the battery is physically connected to the derailleurs via cables.

Change in the design dedicated to braking, since the ServoWave concept is not included. When you squeeze a ServoWave brake lever, the pull on the pads is quick at first, so a slight movement is enough for the pads to contact the disc brake rotor. Leverage then comes into play to increase braking force and slow hydraulic thrust, allowing more precise braking over extended lever travel.

The materials used are a little less noble, which explains the additional weight compared to Ultegra. The cassette is also a little heavier by around 20 grams for example on the 11-34 version. Cassette which is on the other hand offered at €73 in public price compared to €140 for an Ultegra.

This is one of the strong points of this 105 Di2 transmission, the cost of spare parts is lower, even on electronic parts such as the rear derailleur offered at €275 compared to €450 for Ultegra. A maintenance budget which is therefore significantly reduced, especially in the event of a fall.

Another advantage of the 105 Di2 is its long cage derailleur, which allows you to accept an 11-36 cassette where Ultegra and Dura-Ace cannot go beyond 11-34 due to a medium cage. Cassette options are 11-34 and 11-36, on the crankset side, 50-34 and 52-36 teeth

Like the brand's other groupsets, the Shimano 105 Di2 transmission is customizable using the E-TUBE PROJECT application on your smartphone. You can configure your transmission the way you want, adjust the speed of shifting, select the number of gears changed with a simple flick of the control, and use the synchronized or semi-synchronized shift functionality.

You can also connect your drivetrain with most cycling computers including Garmin and Wahoo which allow you to track selected speed or battery status.

What difference in weight and on which components?

I have deliberately omitted the cables and hoses which are strictly identical. Here are Shimano's official weights for each component.

In the end, a little more than 200 grams in the end… including 20% ​​at the rotors, a wearing part that can easily be replaced with Ultegra.

The rest unsurprisingly concerns the crankset, derailleurs and levers, including a little over 50 grams for the crankset.

For example, this Origine Axxome GTO mounted with this 105 Di2 transmission weighs 8 kg all round.

On the road

The ergonomics of the levers therefore have nothing to envy of the Ultegra and Dura-Ace whose shape they take. A compact casserole dish that adheres well and gear change buttons large enough to be handled perfectly even with winter gloves.

If on previous generations, we could sometimes hesitate between one lever and the other, this is no longer the case now with buttons which stand out quite well from each other.

Just like the latest DURA-ACE and ULTEGRA drivetrains, the new Shimano 105 features a quieter braking system that is easy to maintain and offers excellent control and power.

Key improvements are a shorter lever throw to reach the contact point more quickly and a 10% increase in pad-to-rotor clearance to reduce noise. So even if the discs have a little less style, performance is not impacted and you can always opt for nicer models once worn out.

Even if the Servo-Wave functionality is not present in the levers, it is not very noticeable. The travel seems a little more linear, nothing more and it will take a little more force applied to the levers to achieve the same braking power.

In terms of gear changes, it's almost as fast and precise as the brand's more expensive groupsets. The cassette is just slightly noisier, but honestly, you have to have the different groups at your disposal to really hear the difference. This is probably due to the lack of HyperGlide+ machining on the cassette teeth.

Shifts are always crisp, even if you shift while standing on the pedals in a bump at over 300 watts. The fact of having equipped this rear derailleur with a long cage did not in any way penalize the general functioning.

It is really only at low cadences that you can notice a shift to a larger sprocket, which is slightly slower and less fluid.

The only regret is that we only offer 11-34 and 11-36 cassettes. Because if this group can be aimed at cyclists or even cyclists who will appreciate this wide range of development, couriers could be interested in this transmission and in this case, an 11-30 option would have been interesting, even if officially, this derailleur does not is not compatible with an 11-30 cassette. But believe me, it still works.

In the end, the main difference is in the chainring changes.

Using the old generation engines of the Di2 groups, the latter is slightly slower when climbing. Please note, I deliberately avoided the use of “slower”, because the passage from one plateau to another is far from slow. Just a little slower than the Ultegra and Dura-Ace Di2 12V.

Shimano had talked about an increased speed of 45% for the transition from small to large chainring on the Ultegra and Dura-Ace, so we lose this 45%. But the fact remains that 45% slower, not many hundredths of a second…. that's still very fast.

But again, you have to manipulate all these groups to really realize it. Because even without releasing the watts on the pedals too much, the transition from small to large chainring remains clear and without any hesitation. The transition from the large to the small plateau remains as lively as ever.

And you can always opt for a semi-synchronized mode, which automatically switches from one chainring to another depending on the position of the chain on the cassette for perfect and fluid layering of developments by reducing holes or duplicates to a minimum .

Whether you buy the groupset alone or on a complete bike, the Shimano 105 Di2 groupset is always better placed than the competition SRAM, with its Rival AXS. On a complete bike, very often, €500 separates the two groups, with on the other hand 200 grams of points for the SRAM Rival AXS.

And between a bike mounted in 105 Di2 and the same model in Ultegra Di2, it's a total of €1000 that you have to add to be entitled to the higher range.

With

So, is this 105 Di2 R7150 12-speed groupset a good one? Very clearly, yes. Many find it “expensive” for a 105, but this ignores the fact that it remains much better than an 11-speed Ultegra Di2, taking up many of the concepts that appeared on the 12-speed Di2s in its own right.

Its general operation is close to the Ultegra Di2 while being more accessible…. and also less expensive than a SRAM Rival, which operates less quickly and weighs 100 grams more.

Only the braking sensation is a little less comfortable than on the Ultegra and Dura-Ace models equipped with ServoWave, but this in no way penalizes the general power and stopping distances.

Thanks to this group, Shimano makes it possible to offer an electronic group (almost obligatory on most modern bikes) while limiting the overall budget of the bike. Yes, it will always be too expensive, but with this 105 Di2, you have access to an electronic transmission which makes almost no compromise on the latest technologies, while being less expensive than the competition.

Photos : Sonam.cc and Bike Gear