US Lotus Elise Chassis

Elise Chassis Basics

The key to the Elise's featherweight and its immense rigidity is its extruded aluminum chassis. The Elise chassis is an aluminum tub that creates a backbone for all of the other pieces of the car to be hung. The Elise tub chassis is made by Hydro Aluminium (automotive group) a company that makes many aluminum products for high-end auto manufacturers.

Twenty-six pieces of extruded aluminum are used to create the Elise chassis. The extruded aluminum pieces are glued and "riveted" together creating a layer of material that is both lightweight and remarkably stiff. The rivets used in this process are used to hold the pieces together during curing and also give the chassis some resistance to "peeling" during an accident.

Elise Chassis Weight and Rigidity

The Elise chassis weighs approximately 160 pounds a weight savings of over 50% of a conventional steel welded chassis. The S2 Elise differs from the original S1 by reducing the height of the doorsill side rails. The reduction in doorsill height made entry and exit in the S2 a much easier feat without dramatically adversely affecting chassis rigidity. To reduce the doorsill height, the side of the chassis was cut down slightly and then re-enforced with bonded and interlocked pieces. The result was a chassis that a slight reduction in bending strength but an improvement (approx. 7%) in torsional rigidity. The added bonded material also resulted in a slight weight increase of about 9 lbs over the original S1 chassis.

The result of this process is a very stiff chassis that does not need a roof to maintain its rigidity. A "hard top" can be fitted to the Elise but only serves a purpose of keeping the water out not enhancing the chassis rigidity.

Elise Safety

The Elise chassis is also very safe in an accident. The strong chassis and progressively collapsing front crumple zones are quite effective. What is not generally known, is that not only does Lotus design and develop suspensions and engines for other manufacturers; it also does secondary safety work as well. In fact, Lotus has designed the crash structure for the Aston Martin Vanquish.