With the new 105 Shimano is converting one of the world's most popular and widespread racing bike groupsets to an 11-speed drive, thus allowing 22 gears. The 105 5800 inherits the key technologies and features of the groups introduced in previous years Dura-Ace and ultegra.
Among the main innovations in the 105 include an 11-speed drive, which is said to shift more precisely and smoothly than the previous 10-speed groupsets, the optimized braking performance and numerous features that ultimately contribute to improved wheel control and control.
Like the two top groups of the Japanese, so should the 105 characterized by the same fascinating ease of movement combined with clearly defined indexing. A property that is partly due to the polymer-coated cables and partly to the new, optimized design of the brake and shift levers, front derailleur and rear derailleur. This is where Shimano's philosophy of systems engineering. All components and parts were individually developed in such a way that they should work together optimally and with maximum precision as a group, as a system.
The brake shift levers of the new 105 now have the reduced diameter in the grip area, which has noticeably improved ergonomics, comfort and control while driving. In addition, the levers can be adjusted by 10 millimeters in reach using an adjusting screw and thus optimally adapted to any hand size. This is a decisive advantage, especially for women or men with smaller hands. At the front derailleur, the extended lever arm in combination with a new spring mechanism ensures impressive performance. A new spring mechanism is also used on the rear derailleur, which, in conjunction with the optimized cable grid, offers excellent shifting performance and precise adjustment options.
The groundbreaking four-arm design of the crankset has now also found its way into the middle class of road bikes, also from its big sisters Dura-Ace and ultegra to 105 was passed on. Excellent power transmission and the ideal balance between rigidity and low weight are also at a higher level here. The uniform pitch circle makes it possible to realize all translation variants with just one basic crank, chainrings are available with 34, 36, 39, 50, 52 and 53 teeth.
The 11-speed cassette has lower gear steps or switching steps, which help to better maintain the cadence and thus the riding rhythm. It is available in 12-25 tooth, 11-28 tooth and 11-32 tooth versions. The new chain features Shimano's Sil-Tec coating for minimal friction values and maximum durability in all conditions.
Compared to the previous group of 105 5800, the 5700, the Japanese have also made the braking system more efficient and increased braking power by 10 percent. The new dual-pivot brake calipers with symmetrical pivots are largely responsible for this. The new brakes are rideable with 28C tires due to the increased arc of the brake calipers, and special direct-mount brakes are also available. The two color options of the group, available from June 2014 in black and silver, allow optical freedom of choice.
In addition to the new 105 Shimano also presents a mechanical-hydraulic brake-shift lever solution - the logical consequence of the Di2 variant introduced last year ultegra-Level. The engineers have managed to integrate a mineral oil cylinder including a complete braking system into the still very compact mechanical lever. The hydraulic disc brakes are characterized by consistently high braking performance regardless of weather conditions. The innovative heat management is responsible for this. In addition, the braking performance can be precisely adjusted to the conditions, the terrain, the physical requirements of the driver and his ability. Hydraulic disc brakes deliver more stopping power with less operating effort. For optimum ergonomics, the grip width of the brake lever can be adjusted by 10 millimeters, offering equally high controllability for people with small and large hands.
The BR-R785 hydraulic disc brake caliper presented last year will be replaced in future by the new, revised BR-RS785 brake caliper. In particular, the developers have once again optimized the wiring. Instead of using a banjo connection on the inside, as before, the brake line is now attached to the outside of the brake caliper with a straight connection.
The new brake solution is also with the groups Dura-Ace and ultegra compatible.