Z4 Roadster Will Hit the Road March 2019, M40i Coming 2020
Eight-speed Steptronic Sport transmission
Both models of the new BMW Z4 Roadster, sDrive30i and M40i, come equipped with a standard eight-speed Steptronic Sport transmission with shift paddles on the steering wheel. Besides a wider ratio spread, the latest version of the automatic transmission offers even sportier gear shifts. The shorter ratios for the transmission’s lower gears improve acceleration and the unit’s improved internals allow it to operate more efficiently. The transmission features Launch Control for accelerating hard from a standing start with maximum traction. The eight-speed Steptronic Sport transmission fitted in the BMW Z4 M40i has been configured with M-specific shift characteristics to complement the straight-six engine’s power delivery.
New chassis: increased agility and comfort
The chassis technology in the new BMW Z4 Roadster has been developed to deliver the best possible agility and handling dynamics, thanks to a newly designed double-joint spring strut suspension at the front and a new five-link suspension in the rear, a first for a BMW Roadster. This chassis combination offers the best balance between sports car handling and ride comfort. The front suspension sub frame and control arm mounting points are extremely rigid, which lends to precise cornering characteristics as well as having a beneficial effect on the drivetrain’s acoustics.
The sports car tuning of the front suspension dynamics aids the new Z4 Roadster’s steering precision. Aluminum control arms and swivel bearings reduce unsprung weight resulting in superior agility and efficiency. The new rear suspension also employs a lightweight aluminum/steel design. The large supporting base and very rigid structure of the rear axle subframe as well as the bracing used for connecting it to the body result in extremely precise wheel guidance.
Another standard feature is the sport steering with variable power assist and ratio. This particular version of the power steering system is designed to promote not just straight-line stability in the new BMW Z4 Roadster, but also provide precise feedback during cornering and effortless low-speed maneuvering.
The car’s impressively sporty handling characteristics are aided by powerful lightweight braking and Dynamic Stability Control (DSC) systems, whose wealth of features includes the Anti-lock Braking System (ABS), Dynamic Traction Control (DTC), Cornering Brake Control (CBC), and Dynamic Brake Control (DBC). The standard Performance Control function gives the new BMW Z4 Roadster even nimbler handling by varying the distribution of drive torque to the rear wheels according to the situation at hand.
continued…
