In its efforts to keep additional weight for the hard top version as low as possible, Mazda used two different kinds of materials, sheet moulding compound (SMC) for the outer panels and glass fibre-reinforced polypropylene (GFPP) for the inner panels of the retractable roof.

SMC material is a fibre/plastic composite material with high rigidity and heat resistance and, to the joy of the designers, is easily formable into shapes that would never be possible with steel or aluminium. And SMC's smooth surface structure gives an excellent paint finish, which contributes to high levels of build quality and craftsmanship. GFPP combines the virtues of low weight and high strength. This material allowed the inner panels to have a dimpled surface, which looks so good it doesn't need to be painted. For these reasons, Mazda engineers could do without a moulded roof liner - the combination of SMC and GFPP makes the MX-5 Roadster Coupe's hard top just 20 mm thick as a result.



The Power Retractable Hard Top Weighs just 18 kg more than the Soft Top

These materials also ensure that the hard top structure is light and compact. The roof itself (not including rear deck cover) weighs only 18 kg more than the soft top of the Mazda MX-5. And not only that, owners of the MX-5 Roadster Coupe can also transport a case of 12, 1.5-litre bottles upright in the boot, even with the top down.

Wind management has also been perfected with the new MX-5 Roadster Coupe. Naturally, Mazda roadster fans have the most fun with their car when a warm summer breeze blows through their hair. This would not be the case with cabin turbulence blowing on their neck in the process. To avoid this with the MX-5 Roadster Coupe, whose rear deck is nearly 40 mm taller at its front edge, designers added an air guide made of polypropylene to the standard aero board behind the seats. This air guide runs the entire width of the aero board and forces air flowing forward from the back of the vehicle upwards.

Designers improved drive comfort even further by lowering cabin noise levels on the motorway. At a speed of 120 km/h with the top up, the measured noise level was reduced by 8 dB for the MX-5 Roadster Coupe.



Body & Chassis - Not a Gram too Much

- Weight increase is only 37 kg
- Additional body shell reinforcements compensate for larger body openings
- Slight modifications to suspension tuning

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 were needed for the roof itself, the rear deck cover and other small related parts; 3 kg for the steel (rather than aluminium) boot lid, 1.6 kg for the complex wiring harness switches, 0.3 kg for additional material at the aero board and for trim configuration modifications and 1.4 kg for the additional body reinforce- ments and sound insulation features.

Because 2006 MX-5 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.

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