Developed for Mercedes-AMG: the new ST XTA plus 3 coilover with top mounts

The Mercedes-Benz A-Class has long reached the premier league of sporty compact models. For the three recent models Mercedes-AMG A 35 4MATIC, Mercedes-AMG A 45 AMATIC+ and Mercedes-AMG A 45 S 4MATIC+, our brand ST exclusively offers our best ST coilover: the ST XTA plus 3.

The Mercedes AMG four-cylinder engines, driven by twin-scroll turbochargers, produce between 306 and 421 hp in standard production. It’s not surprising that the three compact AMGs dispose of a factory-installed all-wheel drive in order to bring traction to the road.

On the 4MATIC+ all-wheel drive – in the A 45 and A 45 S – the drive train has full variable torque distribution, which enables the rear axle to push along more. Those who use driving programs such as Race Mode can put driving power on the rear axle and enjoy their “drift mode” in the 387-hp A 45 and 421-hp A 45 S if they wish.

Only the best parts of ST suspensions for the Mercedes-AMG

The fact that ST suspensions aka Suspension Techniques belong to KW automotive has been known for a long time. You can find out more about this in our KW automotive blog archive. Obviously, the development of coilovers also benefits from this. Thus, we teased a real suspension highlight on our KW automotive Virtual Expo at the end of 2020: the ST XTA plus 3.

View of the ST XTA plus 3 compression valve setup

This ST coilover, has officially been available for more and more sports vehicles since March 2021. The newly developed KW shock absorbers, with their 3-way adjustable damping forces for street cars, are what make the XTA plus 3 special.

The compression can be set in the high-speed and low-speed

A shock absorber with 3-way adjustable damping forces is by no means only high-tech for motorsport applications or track day sports cars. For several decades, we have been proving like no other aftermarket suspension manufacturer, that there’s no way around transferring sustainable technology from the world of motorsports to the road.

The high-speed and low-speed compression valves of the ST XTA plus 3 coilover, which can be adjusted via 24 precise clicks each, offer the capability to further refine the suspension tuning we’ve preset for your car. It’s not by chance that ST has the claims “Your Car. Your Style. Your Suspension.” and “Make_it_Yours”.

Generic ST XTA plus 3 characteristic diagram

With the ST XTA plus 3, you can manually adjust how your ST coilover dampens during different driving maneuvers and track conditions by using separate compression and rebound settings. You can also make use of the low-speed compression to influence how the Mercedes-AMG A 45 S 4MATIC+ reacts when driving over long bumps, braking, starting off and even when turning-in.

As every passionate AMG fan knows, there is barely a more powerful all-wheel-drive compact sports car than the A 45 S with its 421 hp. The Audi RS3, Ford Focus RS and VW Golf 8 R remain in a completely different performance dimension. Equally, the Hyundai i30 N Performance and Honda Type R are weaker. Even from Munich Garching, the BMW M2 Club Sport, with an even more powerful turbocharged inline six engine, competed with the other compact sports cars in spring 2020 to make the rivalries exciting again.

Nevertheless, when there are extremely wavy asphalt surfaces, transverse joints and transverse grooves, the damping must react faster. The piston rod velocity in the damper is much higher. This can also be adjusted with 24 clicks on the XTA plus 3 via the high-speed compression valve. Turning the high-speed adjustment wheel changes the valve spring preload.

When the valves are closed, the body roll is reduced even more. Therefore, the handling is improved and track stability is increased. When the valves are opened, the rolling comfort benefits. By the way, due to the use of the KW valve technology in the three-way adjustable shock absorbers, the ST XTA plus 3 no longer requires a reservoir.

While the two compression valves can be set in high-speed and low-speed with 24 clicks each, there are 16 clicks to choose from for the low-speed rebound. The rebound mainly affects the vehicle’s connection to the road surface, its bodywork control, and handling. Just like the ST XTA coilover, which can only be adjusted in rebound, the ST XTA plus 3 coilover also disposes of top mounts for camber adjustment on the front axle and linear racing springs.

Evidently, the STA XTA plus 3 coilover has a technical parts certificate. Hence, you can make the automotive expert enter this in your registration papers. It is possible to set a stepless lowering on the three models of the Mercedes-AMG A-Class (W177) A 35 4MATIC, A 45 4MATIC+ and A 45 S 4MATIC+.

Within the scope of the technical parts certificate, a lowering of 10 to 30 millimeters can be chosen for the front axle and 5 to 30 millimeters for the rear. Incidentally, when you opt for this adjustment, the spring travel is still left so that the Mercedes-AMG can still drive on badly constructed side roads. This means that you can still enjoy the residual driving comfort.

ST Make it Yours – the liberty to customize your suspension

When we talk about our ST Make it Yours customization program, we refer to much more than an approved lowering on request for the ST coilovers and ST coil springs. Neither do we simply relate to the adaptation of the damper setup on selected ST coilovers, such as the ST XA, XTA and STA plus 3. Instead, we offer all our customers the possibility to order their suspension springs in one of 18 RAL colors and to add a personal spring marking.

Apart from that, we offer several spring kits for selected suspension applications (ST XTA and ST XTA plus 3). These suspension springs differ from the ones which are already mounted on the coil strut in their spring rate and spring length. Find out more on our ST suspensions homepage:

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