Suspension

Suspension

The suspension system used on MINI provides a firm and responsive ride with superb levels of comfort and good acoustic properties. The weight distribution between the front and rear axles is biased to the front due the front wheel drive configuration.
Adjustment to the camber at the front and rear suspension is not possible, only the front and rear toe is adjustable.

Power assisted steering using an electric pump and ABS is standard, with DSC available as an option on MINI COOPER. ASC is standard on the COOPER S, DSC is optional.

Front Suspension
The front suspension design features anti-dive and anti-squat geometry via the anti-roll bar and 1:1 strut movement ratio. The layout of the design minimizes camber loss due to side forces, thus improving handling and steering response.

Advantages of MINI Front Suspension
Firm and Responsive
Positive Driver Feedback through Steering
Strict Camber Control

The front suspension consists of the following main components:

- Front Subframe
- Lower Control Arms
- Anti-Roll Bar and Links
- McPherson Struts
- Front Shocks
- Front Springs
- Front Top Mount
- Front Hubs

System components

Front Subframe
A main component of the front suspension is the Subframe. It is made from hydro-formed steel tubing and bolts directly to the body. The subframe provides the location for all suspension and steering components with the exception of the upper strut mounts. Attached between the front of the subframe and the bumper are the crush tubes. These tubes are attached with two bolts to the subframe and are designed to deform in an accident.


Lower Control Arms

The pressed steel lower control arm links the subframe to the hub assembly via two ball joints. The inner joint is bolted to the subframe and the outer joint to the hub assembly. The rear of the lower control arm has a hexagonal shaft onto which the compliance bushing is press fit. The compliance bushing is attached to the body with a single mounting and to the subframe with two bolts, which also secure the anti-roll bar.

As the suspension moves, the lower control arm pivots on the inner ball joint. The linear movement of the suspension is changed to rotational movement of the lower control arm, which is controlled by the radial stiffness of the compliance bushing.

Should replacement be necessary a new bushing and housing assembly will be required. Both ball joints are available as separate service parts.

Anti-Roll Bar and Links
Two sizes of anti-roll bar are used at the front axle: 19 mm for MINI COOPER and 24 mm for the COOPER S.

The anti-roll bar bushings clamped to the top of the compliance bushing housings are manufactured from low friction PTFE. This material requires no additional lubrication. This allows the anti-roll bar to rotate freely and quietly. It also allows the anti-roll bar to respond quickly to roll inputs and the use of stiffer bushings, as there is no compression or twisting as found on conventional bushings. Washers attached to the anti-roll bar located on the inside of each bushing prevent sideways movement.

The anti-roll bar links have ball joints fitted at each end. The ball joint attached to the strut is mounted on the same axis as the link. The ball joint attached to the anti-roll bar is mounted at 90� to the axis of the link and is attached to the front of the anti-roll bar with the nut facing rearwards.







The ends of the anti-roll bar are attached to the struts by a link. This allows the anti-roll bar to act on a 1:1 ratio to road wheel travel providing maximum effectiveness.

McPherson Struts
Two McPherson struts control the damping of the front suspension. Each strut assembly consists of a damper unit, a coil spring and a top mount assembly. The coil spring is retained in a compressed condition between the strut spring seat and the top mount. Isolators at each end of the spring reduce noise transmission from the suspension to the cabin. A bearing is fitted to the top spring mount that allows the spring to rotate as the steering is operated. The coil spring axis is offset to the axis of the damper. This arrangement reduces friction between the damper and piston during cornering. A dust cover protects the piston rod from dirt ingress. No provision is made for camber adjustment at the top mounting.


Front Shocks

The front shocks are designed as twin-tube gas pressure shocks, similar to the E46. The lower end of the damper is inserted into a cylindrical sleeve on the swivel hub. The damper bracket determines the correct orientation of the damper; the bracket slides into a machined slot in the swivel hub cylindrical sleeve and is secured with a pinch bolt. A label is adhered to the damper for side identification. The top mounts attach to the body with three studs and are replaced as a complete assembly. There is no provision for adjustment of the camber at the front top mounts.


Front Springs
The spring mounts between the seat on the damper body and the top mount, and is color coded to suit the suspension type and equipment level of the car.

Top Mount
The top mount assembly includes the top mounting plate, with a bonded rubber bushing and integral metal sleeve; three studs are pressed into the plate to retain the assembly to the body. The steel insert in the bushing prevents the damper rod retaining nut from over compressing the bushing when it is tightened. The bushing is not serviceable and a new top mount plate assembly must be fitted if replacement is required. Three lugs on the underside of the top mount plate provide location for the top mount bearing. The bearing is available as a service part separate from the top mount plate.

General Suspension Data


Rear Suspension

Advantages of MINI Rear Suspension:

- Rear Passenger Comfort.
- Noise Optimization.
- Firm and Responsive Suspension.

The BMW developed multi-link rear suspension is used for all models of MINI, making it the only car in its class to use such a sophisticated system. Benefits of this suspension are the exceptional handling characteristics and ride comfort, with good acoustic properties. Main components of the rear suspension include:

- Rear Subframe.
- Trailing Arms.
- Lateral Links.
- Anti-Roll Bar.
- Rear Springs.
- Rear Shocks.

System Components

The fabricated subframe is attached to the body by four bolts. The inside bolt (3 on illustration) on the left side of the subframe is the master bolt to ensure the subframe is in its correct lateral position. The subframe also provides attachment points for the fuel tank straps and rear suspension lateral links. The anti-roll bar attachment points are on the top of the subframe and cannot be seen on the illustration.


Trailing Arms

The trailing arms are fabricated from steel with a wall thickness of approximately 4 mm. The trailing arm provides toe-in control; counters brake lift and provides a low roll center. The arm also provides attachment for the brake caliper, damper unit and anti-roll bar. The trailing arms have two attachment points for the upper and lower lateral links to aid in the track control.

Attached to the front of the arm is the compliance bushing and housing. The housing is attached to the trailing arm by a single bolt. This controls side-force steer performance and enhances ride and noise levels. The bushing is located in a fabricated bracket held to the body by three bolts. The boltholes in the bracket are slotted to allow for toe-in adjustment. Correct orientation of the bracket to the trailing arm is important to ensure correct wind up when fitted to the body


Lateral Links
The lateral links control the track of the rear wheels and are made of fabricated steel with elastokinematic bushings at both ends. The bolts locating the lateral links to the subframe and trailing arm should only be torque tightened with the car in curbside condition (full weight of the car on the suspension). The lateral links are not side specific. The two lower lateral links have protective covers fitted (forward facing) to protect them from becoming damaged by impact.


Rear Anti-Roll Bar
The anti-roll bar is attached to the top of the rear subframe by two PTFE bushings secured with clamp plates. The low friction PTFE bushings allow the anti-roll bar to rotate freely and quietly and require no additional lubrication. The anti-roll bar is made of solid spring steel. The anti-roll bar links from the anti-roll bar to trailing arm have ball joints at both ends and can be installed only one way, with the ball joints on the inside.

Rear Springs
Coil springs, manufactured from silicon steel, are fitted to the shock assembly The springs are retained at the lower end by plates attached to the shock. Between the spring and shock is an isolator. The top of the spring is contained with an isolator and cup that is clamped between the shock rod and rebound plate by a nut.

Rear Shocks and Top Mounts
The shocks at the rear are of the twin-tube gas pressure design, and like the front axle, the rear shocks are side specific. The shock rod is located in a bushing in the top mounting and is secured with a rebound plate and a locknut. The top mounts are side specific and identified by the letter "R" or "L" and attached to the body by two bolts.