Suspension and handling on the MINI, although feels good out of the box, can be significantly improved with a few choice upgrades. Over the years we have worked on many different MINI’s and have tried many combinations of suspension components. What does the MINI feel like as standard? Most standard MINI’s feel great on a smooth road surface which is free from pot holes and ruts in the road. However most roads are not perfect and we have to deal with bumps and pot holes every day, whether go out for a spirited drive or on our daily commute. MINI have of course been trying to improve things with each Generation, but anyone who has ever driven a Gen 1 Cooper S on stock suspension with Run-Flat tyres will remember the teeth shattering “bang” that went through the car every time you hit a pot hole. If you push your MINI harder on a spirited drive, you may have noticed that sometimes it didn’t feel too sure over bumpy surface and you were left with a feeling that at any moment it may jump into the hedge on either side of the road. Not exactly confidence inspiring when the roads are bumpy and twisty. Run flat tyres, although add an element of security and reassurance, do not inspire confidence, add understeer and reduce the ride quality of the MINI. The nature of their design means they are also hard and unpredictable when hitting potholes, due to a very stiff side wall (the side of the tyres we see) Swapping the run flats out for good quality normal tyres is a good starting point. We favour the Kumho KU39 as good all round road tyre for comfort and grip in wet and dry conditions. If you want to really increase the grip you can always try the Kumho V70A which was fitted as standard on the GP2. The standard spring and damper set up, across the MINI range, is also a fairly average affair and can be upgraded to aid comfort and handling. There are few options at this stage, dampers with original springs, lowering springs or coilovers; the most suitable depends upon your application and driving preference. All MINI’s can be improved with the installation of either springs and/or dampers or coilover kits. Lets examine what each offers.
Springs
A suspension spring is what supports the weight of the car on the damper, if there was no spring the car would simply sit on the floor. Springs also absorb the bumps in the road during driving (dampers help them, but more on that later). Springs have to be of the correct stiffness for the car – a spring that’s too soft won’t hold the car up, but a spring that are too hard won’t be compliant enough and will give a very harsh ride. A very quick and easy way to improve the handling of your MINI is to fit a shorter spring or as most people know them a “lowering spring kit”. These are springs that are designed to replace the original ones but are typically 20-30mm shorter. This will bring the car closer to the ground, which will lower the centre of gravity of the car making it roll less. This will also reduce the gap between the tyre and the wheel arch, making it more aesthetically pleasing. Lowering kits are a very popular modification for people who want to improve the handling a bit without significantly altering the ride quality of the car.
Dampers
The dampers primary job is to control the movement of the car on the road, by controlling how the spring moves. The dampers control how fast or slow the spring will open and close. If you didn’t have dampers on the car, then your MINI would simply bounce along the road uncontrollably after every turn, undulation and bump. This wouldn’t be good either for the levels of grip or passenger comfort. The MINI uses a fairly average damper as standard, but like anything, better is always available. Lohen offer the Koni FSD damper and the Bilstein B12 Pro spring and damper kits. The Koni FSD is a fairly unique product that offers on the move “active” adjustment without the need for sensor installation or motors; these adjust damping level through internal hydraulic valves. This means that the MINI rides more smoothly at slower damper speeds but adjusts to more dynamic driving conditions so does not feel washy, reduces body roll, improves stability and becomes more predictable. The Bilstein dampers offer an improvement over original, but don’t offer the active technology. They are still a great addition if you want to reduce the bounce and give your MINI a more controlled ride. Both the Bilstein and Koni FSD dampers can also be fitted with lowering springs for a combined effect. If you didn’t want to lower the car then you could just fit uprated dampers.
Coilovers
Coilovers are a combined set of springs and dampers, that have been designed to work together. Typically a coilover kit will offer 20 – 50mm of adjustable lowering, as well as rebound and/or compression adjustment on more expensive kits. Some coilover kits also allow camber adjustment with the addition of an adjustable top mount. Coilovers are the best option for ultimate performance on the road or track, and achieve more control over simply lowering of the car, however there can be some sacrifice to comfort over the uprated damper option. Which option is best for me? This depends on budget and application, the more adjustment the coilover has the more we can do to set your MINI up. However remember that a more expensive coilover does not necessarily mean a better car, as you simply may end up paying for features you won’t use. Suspension set up is very much a personal preference and condition dependent, so a general answer is very difficult. And is something worthwhile discussing with our team, 01785 85 99 99 or sales@lohen.co.uk Ask yourself a few key questions:
- Am I going to change damper settings i.e. rebound and compression?
- Are the changes I could make myself going to be any good?
- Am I going to be using the car on track?
- Are my preferences on ride likely to be firmer or softer than standard?
What else can I do to improve the handling of my MINI?
There is a number of other components that effect how your MINI handles and/or behaves on the road. You can add strut braces, anti-roll bars, bushes and drop links. So lets explore some of these. Anti-roll bars (also knows as Sway Bars) Anti roll bars are available for just the rear, or for both the front and the rear. What do they do? Anti-roll bars do exactly what they say on the tin, they reduce the roll of the car. This should keep your MINI flatter through the corner, improving the contact of the tyre with the road and hence improving the level of available grip. Fitting a front anti roll bar with the rear anti roll bar stiffens the whole car and provides a more direct and balanced feel. A larger rear anti roll bar increases front end turn in and reduces rear end body roll. It provides the driver with the sensation of the front being steered through the corner from the rear. Much thicker rear anti roll bars on stiffer settings substantially improve front end turn-in but can also exhibit lift off over steer. Although this can make for a fun handling car, it can be dangerous if you don’t know how to handle lift off over steer. Is size important? The Eibach front and rear kit comes with a 25 mm thick front and a 19 mm thick rear bar, the rear is also 2-way adjustable. This means there are 2 holes on the bar for where the end link attaches allowing for 2 different stiffness settings. The Alta rear anti roll bar is available in both 19 mm and 22 mm diameters both allowing 3-way adjustment. The stiffest setting on the 19 mm Alta anti roll bar is reflective of the softest setting on the 22 mm Alta rear anti roll bar. The 22 mm anti roll bar offers the greatest change in handling but also leads to a more snappy rear end, i.e. lift off over steer.Adjustable end links
When do you need them and what do they allow? Drop links connect the suspension damper or coilover to the anti-roll bar. They transmit the forces between the two components and are ultimately responsible for how effectively the anti-roll bar works. On a lowered car adjustable end links are used to match the drop link length to the suspension to anti-roll bar drop. This means the anti-roll bars are in relaxed state and only activate when body roll starts in the corner.Adjustable top mounts and Control Arms (Camber adjustment)
Why and what it does to the car? Adjustable top mounts and Control Arms allow us to set up the appropriate amount of camber on the front or rear axle. Too much may mean you don’t get the appropriate amount of grip in the straight line under breaking and acceleration. Not enough and you won’t get maximum grip through the corner. The right amount of negative camber increases turn in by maximising the contact patch of the tyre through out the corner and improving stability. This should also decrease your dependence on the brakes as you will carry more speed through the corner. Too much negative (or even positive) camber can increase tyre wear, as the tyre will always roll on the inner or outer edge. In theory a car that only drives in straight line should not need any camber, so those who do lots of motorway or dual carriage way miles may see little benefit. This will be especially true on the rear axle where the tyre contact changes less in the corner. In this instance rear control arms allow us to remove too much negative camber that is produced by lowering your MINI. This will correct the ride and reduce excessive tyre wear.
Strut & chassis braces
The chassis stiffness of your MINI has a big impact on the effectiveness of the suspension and the steering feel. So although not direct suspension upgrades, strut braces, chassis braces and other re-enforcement products play a big part in how the car handles and behaves. In short – if the body of the car flexes in an unpredictable way, then the suspension adjustments are less noticeable and will be harder to feel. The steering will feel woolly or indirect as it takes some time for the chassis to flex before the steering inputs are felt. Front strut braces generally sharpen the steering feel and body braces will help the behaviour of the whole car. If you were building a track car then an expertly installed roll cage not only acts as a safety cell, but also will improve the behaviour of the car.
Bushes
The majority of bushes on the MINI are rubber based which are susceptible to corrosion and softening. Moving away from the traditional rubber bush to a polyurethane bush, such as the Powerflex bushes improves service life and performance of linked components by reducing play between them. These allow individual components to function correctly. As always there are options; standard or race. Standard polyurethane Powerflex bushes firm things up over standard and race further still. The firmest solution is not always the best but in some applications can aid performance but this is usually at the expense of comfort.