Test Long-lasting Shimano Dura-Ace Di2 12-speed groupset

One year after its launch, it is time to take stock of the Shimano Dura-Ace Di2 12-speed groupset in terms of the precision and reliability of its operation. To do this, we subjected it to un test long duration of 15 km. Result: apart from a minimum maintenance requirement, the flagship of the Shimano range lives up to what we could have expected.

About Guillaume Judas – Photos: ©3bikes.fr

=> SEE AS ​​WELL : Montagand adjustment of the new Shimano Dura-Ace and Ultegra Di2 12-speed groupsets

Shimano's flagship group was highly anticipated when it was launched a little over a year ago. As it has been with each of its versions for over thirty years, because the Dura-Ace is always guaranteed to be a bestseller. Facing its competitors Sram Red eTap et Campagnolo Super Record EPS, the Dura-Ace Di2 had to go to 12 speeds. But the world leader in transmission groups couldn't just add a sprocket to the Dura-Ace cassette. This new high-end group also had to bring some new features compared to the previous version, to justify its place as number 1. With wireless communication between shift levers and derailleurs, a silent and frictionless disc brake system, and easy connection to a smartphone or PC app that facilitates many adjustments, the challenge is met.

Nothing very revolutionary, that's true, because the competition is fierce in this field and Sram and Campagnolo also regularly launch themselves into the race for innovation. But with the Dura-Ace, Shimano intends above all to offer a safe bet, a reference version in terms of finish, operation and reliability. This is what you would expect from a very high-end group like the Dura-Ace, especially if you take into account the very high sale price, around €4000..

In any case, strictly speaking, this new Dura-Ace group is between the Sram Red (around €3500 retail price) and the Campagnolo Super Record EPS (around €4500) if we're talking about price. It now has the same number of speeds (12) as its two competitors, and it's even a little lighter in this version with disc brakes (2442 g for the complete group, compared to 2516 g for the Sram Red and 2634 g for the Campagnolo Super Record EPS).

Operation without surprises and minimum maintenance

We were thus able to complete 15 km with the group, between spring and autumn 000., on a Specialized S-Works Tarmac SL7, successively equipped with wheels Shimano Dura Ace C50, Roval Rapide CLX and Fulcrum Racing Speed ​​40. The three different wheelsets slightly changed the bike's behavior, but never that of the groupset, obviously.

And even better: Unlike the previous version of the Dura-Ace Di2 disc, it was never necessary to adjust the brake calipers every time you changed wheels.. The old system is sometimes difficult to adjust to avoid noise or friction at the brake level, with a very small space between the pads and the disc. And the slightest change of wheels, if there is a tiny difference in the positioning of the disc, involves a tedious adjustment of the calipers. With the Dura-Ace version R9270, the problem is almost solved, since Shimano has managed to increase the space between the pads and the disc, without changing the travel of the brake lever. This is a huge advantage over the old version.

Moreover, The brakes work in general much better than the previous version. Not so much in terms of power or stopping distance, but rather in terms of noise, which has almost disappeared except in wet conditions, and in terms of the return of the pistons after hard braking, thus avoiding that period over a few seconds where the pads remain in contact with the disc even after releasing the lever.

In terms of maintenance, we found that the brake lever travel had increased over time. This was even more noticeable when changing bikes for the winter. So we checked the condition of the brake circuit, and found a few air bubbles, but they did not require a complete bleed.

On the other hand A thorough check of the brake pads shows that they are at least half worn, and that it may be time to change them. Nothing abnormal after 15 km, especially since some riders may need to change their pads earlier, depending on their weight and the terrain they ride on. The bike was mainly used in the northern part of France on moderately hilly courses for a cyclist weighing less than 000 kg, and the summer was particularly dry. To change the pads, you need to pay around €50 for the two pairs (front and rear).

=> Buy a pair of Shimano Resin L05A brake pads for €24,99

No worries on the other hand on the discs side (two 140 mm discs here). There is very little wear and these seem set to do at least 40 km. But still under the conditions of use described above. Note that each time we changed wheels, we took care to use the same discs, which were therefore run in with the original pads. For information, Dura-Ace/XTR discs are sold at a retail price of around €90 each. But it is still possible to equip yourself with Ultegra/XT discs for around €60.

=> Buy Shimano XTR-RTM900 brake disc for €61,99

On the brake handle side, The finish of the levers is always very good quality, and relatively insensitive to scratches, except in the event of a big fall. The rubbers of the brake hoods seem a little firmer than the previous version, and less affected by the numerous roll-ups necessary to fine-tune the adjustments of the grips or the changes of handlebar tape. The texture to ensure grip seems to wear a little faster, however.

Compared to the old version of Dura-Ace, 12-speed shifters are more sensitive to vibrations. Nothing really terrible, but still a little noise that can be a bit annoying on routes with poor road surface or driving with high inflation pressure.

Precision and durability

Regarding the gear changes, again there were no (bad) surprises. Once properly adjusted, the derailleurs never moved and the precision was always there. Compared to the Dura-Ace Di2 11, the changes are slightly faster. Not much, but you can tell by switching from one bike to another.

The battery life of the derailleurs is slightly longer than what Shimano claims, and it is possible to do 1500 km without any problem and without recharging. Note however that for our part, we use the small chainring very little, and the front derailleur is therefore rarely in action. And it is a little more energy-hungry than the rear derailleur. Recharging with the specific cable is super fast. It is just unfortunate that it is done by plugging the cable into the rear derailleur, which requires bringing the bike closer to a socket. It is a detail, but depending on the light conditions, access to the charging plug is not very practical, because you first have to find a way to lift the small protective cap on the derailleur and then find the magnetic connection. You can sometimes search for a while in the dim light of a cellar. Nothing to report on the other hand on the button cells of the gear shift levers, which have so far shown no signs of weakness.

La super easy bluetooth connection between the system and the Shimano E-Tube Project application on smartphone or the meter allows in all cases to check the status of the system battery, and to check when it is time to recharge, between two outings.

=> SEE AS ​​WELL : Montagand adjustment of the new Shimano Dura-Ace and Ultegra Di2 12-speed groupsets

This same application allows you to adjust certain settings, such as the position of the derailleurs if necessary or the choice between “normal”, “semi-synchronized” or “synchronized” gear change modes.

Magie electronic transmission, it is also possible to change the function assignment of each of the lever buttons. We stayed with the classic, with the large puck to mount the sprockets on the cassette or pass the large chainring, the small puck to go down, and the buttons hidden under the hoods to change the pages of the connected GPS counter.

=> SEE AS ​​WELL : Everything you need to know about Shimano Di2

The application also offers interesting information: usage statistics for different transmission ratios since the implementation route of the group or for a particular outing.

Beyond the anecdote, it is a function that can allow you to anticipate a change of chainring or cassette, if certain sprockets are used much more than others, and depending on the conditions. The fact remains that for what concerns us, the cassette is still good for use after 15 km. Fortunately, because even with the use of three pairs of wheels, we had to put the same cassette back each time. The first year of marketing of the Dura-Ace groupset was a bit chaotic in terms of the availability of spare parts. For the price of a replacement cassette, it stings a little, since it costs around €350. Note that the Ultegra 12-speed cassette is of course compatible, and that it sells for around €120.

=> Buy Dura-Ace 12 speed cassette for €299

To preserve the tape, It is necessary to change the chain regularly, to limit the wear of the teeth caused by its excessive elongation. We changed the first two chains after about 5500 km each time, measuring the elongation with a wear tester. Contrary to some fears, there is no significant difference in wear between the 12-speed chains and the 11-speed chains. Note however that despite a sporty practice, we did not participate in competitions with frequent restarts, the chain crossings were very rare, and the group was testis generally in mild weather. In more extreme conditions, you should probably change the chain a little more often, always with the aim of preserving the cassette and chainrings as much as possible. To replace a Dura-Ace chain, you need to pay around €70.. The Ultegra chain is also compatible, for around €60.

=> Buy Shimano XTR CN-M9100 12v chain for €59,99

While the chainrings do not show any particular wear and seem to be able to ride for a long time, their finish is very sensitive to scratches, when replacing the chain, when transporting the bike or when adjusting the derailleurs. And of course in the event of a chain jump, something that fortunately almost never happens. The cranks have the same problem. Looking closely, the beautiful black anodizing is very fragile.

Finally, on the subject of wear parts, a word about bearings. Although not exceptionally smooth from the start, The derailleur pulleys continue to operate smoothly, without snagging or noise, even after 15 km. Nothing to say on that side, reliability is there.

For the bottom bracket, it should be noted that there was no specific model produced by Shimano for the 12-speed group. And given the number of formats on the market to suit different frames, the brand preferred to continue to offer (as an option) the bottom bracket from the previous group. A bottom bracket that is again not super fluid, but which is likely to last at least 45 km according to our own experience. Note, however, that for this montage specific with external bearings in BSA format, we opted for a Ceramic Speed ​​case, super fluid and which has not moved in 15 km, and without the need for any maintenance.

Conclusion: a group that lives up to its reputation

So of course, The Dura-Ace Di2 12-speed groupset is particularly expensive, although it must be compared to its direct competitors Sram Red eTap and Campagnolo Super Record EPS. And of course, the technologies used for gear changes, braking and connection to the app are the same as for the Shimano Ultegra Di2 12-speed group, sold for around €1500 less, and which only weighs a little over 230 g more on the scale.

More The materials used on the Dura-Ace, in addition to being lighter, also show their durability, as was the case on previous versions. And in fact, there is very little maintenance to be done on such a group, except for a change of chains every 5000 km or so, and perhaps brake pads every 10 to be on the safe side. The teeth of the cassette and chainrings are solid, and only the anodization of the crankset is a little disappointing. For the rest, The group works like new, even after 15 km.

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