The general arrangement of JCB DIESELMAX places the front engine and its transmission ahead of the driver's safety cell, and the rear engine and transmission behind.

This layout is attractive not least because of the optimisation of weight distribution but because it places the driver in the best possible position to monitor the behaviour of the car, and the safest place should there be an accident. Chief Designer John Piper has opted for a 50 mm square-tube steel spaceframe chassis. This is the most cost-efficient way of producing a vehicle that must be both prototype and finished product, since it allows changes to be made much more simply than might be the case with a carbon fibre composite structure (which in any case would not be allowed under the SCTA-BNI rules that govern Bonneville Speedweek).

The cockpit cell is a bespoke carbon fibre composite bathtub monocoque structure with mandatory SCTA steel tube rollover cage. The nine-litre wedge-shaped fuel cell is located behind the driver's seat.

A three-piece composite underfloor completes the basic structure, and is bolted and bonded to the bottom of the chassis to enhance stiffness.