Owning and driving a Mini is a lot of things to a lot of people, but one of the most common attractions is the “handling”. A stock Mini that was designed long before the advent of the modern computer generated car, can put more satisfaction in the simplest use than anything on the road today. All of the often over-used attributes of “classic”, “best-ever”, have always been a part of the heritage of this great car.
So if the stock Mini is so great, why is it so common for people to want to make it better; because it is easy and the results can be pretty exciting. The stock Mini was built to out handle period cars of the day, the VW, Morris Minor, Triumph Hearld, etc. Today, our roads are better, our competition is getting better and our expectations are ever rising.
The very first basic step to be sure the fundamental design features are up to at least stock as new condition. The front suspension of ALL Minis is located by a simple set of rubber bushing. If these bushing are worn and ignored, the very basics of camber and caster will be upset. More details reference camber and caster can be found here.
First step for improvement: Tires!
Most every stock Mini produced was shipped with ‘145’ tires in either 10” or 12” diameter. The’145’ indicates a measure of width and thus an upgrade to ‘165’ tires even on stock rims will result a very noticeable improvement. Tires are a must have, wheels are a real bonus.
Second Step: Rear Sway Bar!
Although several to choose from, the expected results are all the same; induce oversteer! Yes, the intent is to cause the rear tires to absorb more of the load in cornering and take some of the pressure off the front tires! The front wheel drive Mini not only drives the car forward with the front tires but also has the greatest influence on cornering speeds. With limited tire width, these tires have to both control drive and cornering and thus any transfer of effort to the rear will result in better overall corner speeds. While fixed rear bars (based on years of experience) adjustable rear bars allow for final tweaking for driver individuality!
Third Step: Camber modifications!
As explained earlier, keeping the often considered “skinny” Mini tires in total contact with the ground is the epitome of a great handling car. Body roll, suspension geometry, etc. all impact this ultimate solution. But as all suspension is a compromise, so too is camber. The maximum effort needed from a tire is during cornering and thus it is very much affected by body roll, etc. It is not uncommon to have the outer edge of the wheel actually off the ground when going in a straight line just to insure we have the absolute maximum when cornering. The short story is that we must have negative static camber in a Mini to increase cornering ability. The wider the wheel and tire the less negative needed. But as a rule of thumb, street cars should have at least a ½ degree negative camber while race cars could have as much as 2 ½ degrees negative! Adjustable and fixed lower arms are available. Remember most stock Mini suspensions actually have positive camber. Fixed arms such as the C-AJJ3364 are degrees of change and not necessarily a measure of end results. IE. If the stock suspension has a positive 1 degree and you then add these arms, the result will be ½ degree negative!
Fourth Step: Hi-Lo Suspension
Changing the ride height of the Mini can indeed result in dramatic handling improvements. While this too can be a very technical rational, the bottom line is that the lower to the ground a vehicle can be optimized for, the better the cornering speeds. The added benefit of being able to adjust corner weight may only be important to the rear racer but every little bit helps! PS- it is very common to alter comber as you lower your Mini!
Fifth Step: Uprated Shock Absorbers
Stock shocks are more than adequate for stock applications. The first upgrade is simply one that will last longer! The second level is one that is “gas” filled in place of the stock “Oil” filled. The “Gas” will not overheat under extended hard use and thus will work better. The next step up is “adjustables”! These shocks will allow more control of shock characteristics over an extended period of time.
These are the basics, if you are looking for more and your Mini is more than 10 or 15 years old it will probably benefit greatly from some new springs on all four corners. Now the question is do you go with new generation “Coil” springs or simply a new original Dunlop rubber cone. NOT an easy decision; if your Mini is primarily a street car there is no question that the modern coils will make the car ride better (Smoother). Even when you opt for the stiffer coils it will for sure ‘feel’ better! But if you have any sort of competition in your plans the decision is not as easy. The “Coils” are not legal in most if not all Vintage Race organizations and while hard to detect, also probably not legal for Autcrossing as well. Can a “Coil” sprung Mini be as quick as a Rubber cone version? Probably! But the primary benefit of coils can also be a problem for full competition. While cornering speeds may not be compromised, the body roll inherent in the coils can be a bite disconcerting. The solution for most is to also install a front sway bar. Now understand that any sway bar is only a means to compensate for a suspension that is not doing what is expected. Thus a rear bar is added to cause the rear end to “loose grip” so as to balance the front suspension that has not enough grip. Result; both ends of the car have the same slip angle and thus is controllable (although not always quick!). Balance, Balance, Balance; this is what it is all about, balancing the front tire adhesion with the rear so that corning can be done with comfort and ease!
So what is all the hype about shocks? Yet again shocks are designed to control the suspension springs NOT replace them! A “Stiff” Mini is not necessarily a quick one! Shocks are designed to control the rebound of springs NOT the initial spring pressure. Shocks are designed to keep the wheel in contact with the road under all conditions not hold the car off the bump stops, that is the job of the springs. The result of all this- shocks should be set (if adjustable) as soft as possible to only keep the tires in contact with the ground! Stiff shocks are not a substitute for the correct spring rate! The real dynamics of shocks should be a discussion all of it own; bounce verses rebound, gas verses oil, etc.
Mini handling is like a bottle of wine? It all depends on who is driving (or drinking the wine)! Experience, technique, expectations all result in a different formula for success.
Additional articles about Mini suspension can be found here