Shimano presented its first hydraulic disc brake for racing bikes and cyclocross bikes at Eurobike 2013. This is on the level of the well-known ultegra-Group. Interestingly, however, it is not compatible with mechanical shifting components. In this point alone, the Japanese model differs from those that Sram has previously launched [regardless of the recall - Link]. We have over the past two months both the Ultegra 6870 Di2 as well as the hydraulic stoppers chased through the winter.
It's not that easy to find a frame that cuts a fine figure both on and off-road and allows the installation of an electronic groupset with disc brakes. The Specialized Crux however, meets these requirements.
In addition to the current Ultegra 6870 Di2 with seat post battery, blades with 46 and 36 teeth are mounted on the crank, we also have the new ones UltegraBrake calipers and Centerlock discs XTRseries installed. We have combined this with a 160mm disc at the front and a 140mm disc at the rear. The setup is rounded off by the also new RX31- Shimano clincher wheels.
The assembly goes relatively well by hand. The cables of Ultegra 6870 Di2 are guided in the frame and can be connected to each other easily as usual. Laying the brake line is also largely problem-free. While one end of the lines is connected to the calipers for the front and rear wheel brakes, the shift levers already have one integrated Management. After all the cables have been laid, the lines are brought together using the connections provided for this purpose. To fill the brake, you first have to loosen the upper cover of the lever. The brake can then be used like any other hydraulic brake from Shimano set in motion.
Although the front derailleur and rear derailleur can be programmed using dedicated software that is only available for Windows computers - here the options range from determining the shift jumps to programming the left lever for the rear derailleur and vice versa - they don't have to be. Actually, you only have to set the stops, the rest is done by both components themselves.
The first thing you notice when you use it is the shape of the handles. Compared to conventional ultegra- Lever they are characterized by a much higher horn, which is slightly lower than that of the US competition. Apart from that, they feel good in the hand, although it takes some getting used to gripping the levers like you would on a racing bike.
The switching performance leaves no room for criticism. Although the Ultegra 6870 Di2 not quite as crisp as the much more expensive counterpart Dura Ace 9070 Di2. [Link] However, one difference is hardly noticeable - only the total weight of the system is slightly higher. The positive is that Ultegra 6870 shifts excellently even under load. This is particularly noticeable on climbs and off-road. The true strength of the electronic shifting system only becomes apparent when it is used on rough terrain. Thanks to the automatic alignment, the chain always stays where it should be. Chain hits do not impair propulsion.
The brakes are also mature. Neither on short descents with an average gradient of up to 12 percent - lUnfortunately, the winter weather did not allow for longer descents in the mountains - even during use under really adverse conditions, you can tell something. We could not determine any fading. On the contrary, they always grab powerfully and reliably. Thanks to the low hand forces required for braking, they are particularly suitable for cycling marathon enthusiasts, but also for riders with small hands, especially women and children. Anyone who is used to using a normal rim brake will certainly have to get used to it, because the word brake pressure definitely redefine Shimano's hydraulic stoppers. And that in a direction that comes more from the MTB sector. The brakes do their job reliably regardless of the weather conditions and they hardly caused any problems even in sub-zero temperatures; the noticeable pressure point was delayed a bit, but the difference remained minimal. The brake is therefore of particular interest to those who swear by the use of carbon wheels, but in the wet and cold suffer must. When driving in mud, the brake discs can grind, which usually resolves relatively quickly.
Ultegra 6870 Di2 together with hydraulic disc brakes, Shimano has brought a group onto the market that the competition has to follow. Thanks to the low attachment to the fork ends, the cantilever-typical brake stuttering, which is often annoying on cross bikes, is eliminated. In terms of both shifting and braking performance, this group takes riding pleasure to a new level in its price segment.
- very good brake pressure in all conditions
- easy maintenance of the brakes and the groupset, battery lasts a long time
- Switching performance without ifs and buts
//price and web
- no official price information from Shimano