The soft top version of the Mazda MX-5 owes its unusually agile
and linear handling characteristics to a strict gram strategy
applied during the development of the third-generation version. One
of the main goals in developing the new Roadster Coupe version was
to keep the unavoidable gain in weight as low as possible. Only by
delivering this, could MX-5's famous Jinba Ittai driving
dynamics be assured for the hard top version as well.
The Roadster Coupe version is just 37 kg heavier than the soft
top model. Of this weight, 30.2 kg come from the roof itself, the
rear deck cover and other small related parts, 3 kg for the steel
(rather than aluminium) trunk lid, 1.6 kg for the complex wiring
harness switches, 0.3 kg for additional material at the aero board
and trim configuration modification and 1.4 kg for the additional
body reinforcements and sound insulation features.
Because the Roadster Coupe's body opening for stowing the hard
top is 45 mm wider and 82 mm longer than that of the soft top
model's, local reinforcements had to be employed to compensate for
a slight loss in body stiffness. These include:
- A 1.8 mm thick reinforcing bracket at both corners of the rear
deck opening,
- Increasing the thickness of the front surface of the rear deck
from 0.7 mm of the soft top model to 1.8 mm for the Roadster Coupe
model,
- Strengthening the sides of the rear deck opening by inclusion
of a closed-section structure that extends through the front
surface of the rear deck.
These local reinforcements make body shell stiffness of the MX-5
Roadster Coupe virtually the same as the soft top model. Here as
well, developers kept the weight gain as low as possible, limiting
it to just 820 grams.
Larger Front Stabilizers and Stiffer Rear Springs and
Dampers Settings
Because there is slightly more weight at the back of the
Roadster Coupe when the hard top is stowed behind the seats,
engineers optimally tuned the rear springs and dampers. At the same
time, a larger front stabilizer is introduced (increased in
diameter from 21 to 22.2 mm) along with new settings for the front
dampers.
These features give the Mazda MX-5 Roadster Coupe handling
characteristics that provide further refinements compared to the
agile and nimble handling characteristics of the soft top.
Driving the rear wheels all MX-5s employ double wishbones at the
front and a multi-link set-up at the rear.
It features large disc brakes front and rear and a stiff, light
and linear power assisted rack and pinion steering system with 2.7
turns lock-to-lock.