S2000 - Chassis

- Low polar moment of inertia and 50:50 front/rear weight distribution for balanced handling
- Low centre of gravity
- Innovative 'high X-bone frame' provides immense rigidity and outstanding impact characteristics
- Strengthened windscreen surround and roll hoops provide added safety
- New generation in-wheel double wishbone suspension
- Torque-sensing limited slip differential
- Electric power steering
- ABS braking

S2000's design ethos demands an unwaveringly secure chassis that responds faithfully to every driver input, and Honda's engineers have come up with a sports car that is sure-footed, fully exploitable and responsive in a predictable and linear fashion. And yet the ride quality remains supple without compromising those abilities.

Several fundamental aspects of the HONDA S2000 design contribute to these characteristics. A light, compact engine positioned well back in the chassis ensures a low polar moment of inertia; the optimum 50:50 front/rear weight distribution for balanced handling; the low centre of gravity; the high level of stiffness provided by the high X-bone frame body structure ensuring consistent suspension geometry alignment; and suspension technology that builds on Honda's racing experience all combine to provide the advanced chassis control.


The high X-bone frame of the S2000

When designing any open car, the loss of a fixed steel roof as a load bearing structure naturally demands compensatory measures to maintain the body's rigidity. Furthermore, in a finely-honed, high-performance sports car it is even more essential that the body provides a highly rigid structure, thereby allowing the suspension to work to its full potential, uncompromised. And, in terms of crash safety performance, it is vital to provide adequate rigidity to allow front and rear crumple zones to operate effectively.

However, adopting a conventional approach to the problem - that is, applying major structural reinforcement to the side sills and central floor - can all too easily increase the weight of the car to a degree that harms performance, fuel economy and emissions performance, while the rigidity rarely matches that of a closed car.

Honda's engineers therefore opted for a totally clean-sheet approach for S2000 and their solution offers rigidity and passenger protection equivalent to that of a closed body, but in a lightweight bodyshell.

At S2000's heart lies what Honda has termed a 'high X-bone frame'. While the bodyshell is in effect a monocoque, what sets it apart is the manner in which the frame rails and centre tunnel combine to form an exceptionally rigid body-chassis. The 'X' element of the high X-bone frame refers to a notably deep centre tunnel, box-shaped in cross section to offer good resistance to torsional loads, and a pair of 'legs' at either end running diagonally. Those at the front connect directly with the front longitudinal frame rails to cradle the rear of the engine; those at the rear abut the rear chassis frame rails.

A key element in this design is the single horizontal plane formed by the top of the centre tunnel and the front and rear frame rails; since they are all set at the same height, they provide immense rigidity. The result is the S2000 body offering torsional rigidity equivalent to that of a closed one and a level of bending rigidity far superior to either open or closed conventional bodies.

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