S-tronic - what is it? Pros and cons. Problems. Flaws.

S-tronic is a bright representative of robotic gearboxes. It is mainly installed on all-wheel drive or front-wheel drive cars. A more correct name would be - preselective gearbox. S-tronic is installed on Audi cars and is practically an analogue of Volkswagen's proprietary Direct Shift Gearbox (DSG).

Similar checkpoints work according to the same scheme:

• PowerShift—Ford;
• MultiMode — Toyota;
• Speedshift DCT — Mercedes-Benz;
• 2-Tronic - Peugeot and many other options.

It is worth noting that along with the S-tronic gearbox, R-tronic is often installed on Audi, which differs only in the presence of a hydraulic drive. The main feature of this type of transmission is the presence of two or more clutch discs, thanks to which the gear shift occurs instantly.

In simple terms, two mechanical gearboxes are successfully combined in one C-tronic, with one shaft responsible for paired gears, the second for unpaired ones. Thus, one clutch disc works at one time or another, and the other is in a disengaged state, however, the gear is already engaged in advance and therefore, when the driver needs to switch to another speed range, this happens almost instantly without any pushes or dips in speed.

Advantages and disadvantages of S-tronic

Those motorists who are lucky enough to be owners of cars with a preselective transmission highlight the following positive points:

• significantly improves the dynamics of the vehicle;
• it takes no more than 0,8 ms to switch speeds, respectively, the car accelerates quickly and smoothly;
• fuel is used more efficiently - savings can reach ten percent.

A transmission such as DSG or S-tronic almost completely smooths out the moment of shifting, so it seems that you are driving in one, infinitely long gear. Well, to master such a gearbox is much easier, since it does not require a clutch pedal.

But for such comfort, you have to endure certain disadvantages, of which there are also many. First of all, this type of transmission has a significant impact on the cost of the car. Secondly, maintenance is also quite expensive. The vodi.su portal recommends adding or changing gear oil only in a specialized service or at an authorized dealer.

In addition, as wear and tear, various problems begin to appear:

• if you decide to accelerate sharply and move from medium speeds to higher ones, jolts or dips are possible;
• when shifting from first to second gear, a slight vibration may be observed;
• possible dips in speed at the time of changing ranges.

Such defects are noted due to excessive differential friction of the preselector.

Preselective gearbox device

Any robotic gearbox is a successful hybrid that combines all the positive qualities of traditional mechanics and automatic transmission. It is clear that a large role is assigned to the control unit, which operates according to rather complex algorithms.

So, when you just accelerate the car to the desired speed, there is acceleration on a pair of gears responsible for the first gear. In this case, the gears of the second gear are already in engagement with each other, but they are idling. When the computer reads the speed readings, the hydraulic mechanism automatically disconnects the first disk from the engine and connects the second, the second gears are activated. And so it goes on increasing.

When you reach the highest gear, seventh, sixth gear automatically engages and idles. According to this parameter, the robotic box resembles a sequential transmission, in which you can change speed ranges only in strict sequence - from lower to higher, or vice versa.

The main elements of S-tronic are:

• two clutch discs and two output shafts for even and odd gears;
• a complex automation system - an ECU, numerous sensors working in conjunction with an on-board computer;
• hydraulic control unit, which is an actuating device. Thanks to him, the desired level of pressure is created in the system and in individual hydraulic cylinders.

There are also robotic gearboxes with electric drive. The electric drive is installed on budget cars: Mitsubishi, Opel, Ford, Toyota, Peugeot, Citroen and others. On the Premium segment models, robotic gearboxes with hydraulic drive are installed.

Thus, the S-tronic robotic box is by far one of the most efficient and reliable. True, the entire Audi lineup equipped with this type of transmission (or the more expensive R-tronic) is a fairly expensive car.

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