Content .. 22 23 24 25 ..

Lotus Eleven/Elise/Exige. Manual - part 24

Page 1

Lotus Service Notes

Section CI

FRONT SUSPENSION

SECTION CI

Sub-Section Page

General Description CI.1 3

Geometry & Adjustments CI.2 3

Anti-Roll Bar CI.3 7

Suspension Disassembly/Assembly CI.4 9

Front Wheel Bearings CI.5 11

For Super Sport Suspension, see DH.6

Page 2

Lotus Service Notes

Section CI

GENERAL LAYOUT

Spring/damper unit

Top wishbone Steering tie rod

Upper swivel

joint

Track rod

end

Steering

arm

Anti-roll bar

mounting

Anti-roll bar

Bottom wishbone

Hub carrier

Wheel hub

Lower steering swivel joint

c34b

Page 3

Lotus Service Notes

Section CI

CI.1 - GENERAL DESCRIPTION

The fully independent front suspension comprises, on each side of the car, upper and lower wishbones, a

concentric coil spring/telescopic damper unit, and a tubular anti-roll bar. A forged steel hub carrier, provides a

mounting for a the hub bearing unit to which the road wheel is attached via four spline socket bolts.

The upper and lower 'A' frame wishbones are fabricated from steel tube, the upper wishbone braced by

sheet steel gussets at its apex, and the lower wishbone braced by a tubular strut at its base. The inboard ends

of both wishbones use replaceable bonded rubber pivot bushes to provide maintenance free articulation, with

a specification providing accurate and responsive dynamic characteristics. The outer ends of both wishbones

incorporate housings into which the upper and lower steering swivel ball joints are pressed. The upper ball

pin is secured to the forged steel, rearward facing steering arm, itself fixed to the hub carrier by two M10 bolts.

The ball pin of the lower swivel joint is secured directly into a tapered hole in the bottom of the forged steel hub

carrier. The Bilstein spring/damper unit acts between the outer end of the lower wishbone and the chassis,

and is fitted with the damper rod lowermost in order to minimise unsprung weight.

A forward mounted tubular steel anti-roll bar, is supported in chassis mounted rubber or hard plastic pivot

bushes and is operated via short ball jointed drop links from the lower wishbones.

CI.2 - GEOMETRY & ADJUSTMENTS

Provision is made for the adjustment of wheel alignment, camber and castor. Under normal service con-

ditions, no periodic scheduled check of the geometry is necessary, although a front wheel alignment check is

recommended when the front tyres are replaced. A full geometry check is required only after front suspension

repair, or if excessive tyre wear is evident, or if steering difficulties are encountered. Before any measurements

or adjustments are made it is essential first to set the vehicle to its ‘mid-laden’ ride height, approximating to

driver and passenger and a half tank of fuel. This will require the vehicle to be ballasted, or tied down:

Standard Elise

Mid-laden ride height (reference height for geometry check);

- front 130 mm below front end of chassis siderail

- rear 130 mm below rear end of chassis siderail

Camber - optimum - 0.1°

- tolerance + 0.1° to - 0.3°; Max side/side 0.2°

Castor - optimum + 3.8°

- tolerance + 3.5° to + 4.1°; max. side/side: 0.35°

Alignment - optimum Zero

- tolerance 0.5 mm toe-out to 0.7 mm toe-in overall

(0.07° toe-out to 0.10° toe-in overall)

Steering axis inclination 12° nominal

Sport Elise, Exige

Mid-laden ride height (reference height for geometry check);

- all except USA prior VIN 3013 - front 130 mm below front end of chassis siderail

- rear 130 mm below rear end of chassis siderail

- USA prior VIN 3013 - front 135 mm below front end of chassis siderail

- rear 135 mm below rear end of chassis siderail

Camber - optimum - 0.3°

- tolerance - 0.1° to - 0.5°; max. side/side: 0.2°

Castor - optimum + 3.8°

- tolerance + 3.5° to + 4.1°; max. side/side: 0.35°

Alignment - optimum Zero

- tolerance 0.5 mm toe-out to 0.5 mm toe-in overall

(0.07° toe-out to 0.07° toe-in overall)

Steering axis inclination 12° nominal

Page 4

Lotus Service Notes

Section CI

Alignment

Wheel alignment refers to the parallelism of the wheels when viewed from above and is crucial to vehicle

stability, handling and tyre wear.

Alignment is measured either by the angle a wheel makes with the vehicle centre line, or the difference in

dimension between the wheel rim to wheel rim measurement at the front and rear of the wheel at hub centre

height. The wheels are said to 'toe-in' when the wheel paths converge ahead of the vehicle, and 'toe-out' when

they diverge. Wheel alignment is designed to vary with both steering angle (Ackerman) and suspension travel

(bump steer) and should be measured only 'straight ahead' at the specified ride height.

Front wheel alignment is adjusted be screwing the track rods into or out of the track rod outer end ball

joints. In order to preserve the required bump steer characteristic and steering symmetry, the effective length

of each track rod must remain equal - adjust each track rod by a similar amount.

Hold the track rod end using the flats provided, and slacken the locknut. Repeat for the opposite side.

Turn each track rod a similar amount. As a guide, turning both track rods by one quarter of a turn will alter

overall toe-out by approx. 2.0 mm.

When adjustment is correct, hold each track rod end and tighten the locknuts to 80 - 82 Nm (58 - 60 lbf.

ft).

When slackening or tightening the track rod end locknuts, it is important that the torque reaction is resisted

using the track rod end flats, and that the ball joint itself is not allowed to be stressed.

Difference between

rim measurements

= overall toe out

FRONT

Individual

toe out

angle

c26

Steering rack gaiter

Track rod end flats

Track rod end

Steering arm

Steering track rod flats

Track rod end locknut

c28a

Content .. 22 23 24 25 ..