First off, as Al says, gets some photos up! Would be great to see another build and also, strictly speaking, this part of the forum is for build threads only but it seems recently it has turned into a more of a Q&A area. However, there is no specific motorbike engine mini Q&A section so I think it is understandable why it is happening.
Please don`t be offended if you already know some/most/all of this, it`s just much easier to start from the beginning. Also, this is not gospel - just what I have found/believe about mini suspension!
A sorted chassis setup & 'good' handling is the sum of many things. Wheel width and diameter determines what tyres you can use & therefore how much grip you can potentially create (=road holding). I say potentially, as tyres only give maximum grip when operating at their optimum temperature (ie warm) and a 13" wide tyre takes much more effort to heat up compared to a 165 section 10" tyre.
This grip level also determines how much roll will be induced into the car. Which will determine how stiff you need your springs to be & form part of the reason why you may potentially look to run Anit-roll bars.
Anyway, you asked about springs & dampers so I will stop babbling on and try and answer your question!
A mini has a relatively small amount of suspension travel (bump/droop) which is why rubber cones work so well. The rubber cones have a progressive spring rate - so they get 'stiffer' the more they are compressed which acts a bit like a built in bump stop. Usually the mini coilover kits have a fixed spring rate and, on the front, are mounted where the mini usually mounts just it's dampers. So the mini was not designed to have strut mounting point here. That doesn't mean it can`t be made to work, but what it does mean is that bolting on a coilover unit, esp with a fixed rate spring, will most probably not give you they same performance as a rubber cone setup can.
Rubber cones come is 3 grades of spring rate.
1) Standard Dunlop OE Cones
2) Red dot (medium stiffness, fast road)
3) Yellow do (Hard stiffness, race)
I would suggest for a road car to use standard or red dot cones. I previously used red dot and did not find them harsh at all & only a small step up from standard. Stay away from the yellow dots as they are very stiff. I have these fitted on the front and I only have 10mm bump and 35mm droop, & quite a firm ride.
So once you have your cones, you will need dampers. It all depends on budget really. What you need is a very quick reacting short stroke damper. Ideally you need to measure the bump and droop of your suspension & match this to a damper. However, if your mini is lowered a moderate amount, any of the off the shelf lowered version dampers will be fine. If it is standard height then just use a standard damper - simples!
After that, suspension geometry, tyre pressures, corner weighting, & roll bars can be used to fine tune the handling or 'balance' of the car.
Edited by duds100, 17 December 2015 - 10:56 AM.