Ok I am stuck in a hotel room as per usual for my mid weeks with a lowly 5 tv channels for perusal. So I was wondering about suspension spring rates and how they work!.
I often hear people say ‘having it too stiff’ ( ) can be a disadvantage!, I can understand this for road driving as it would get skittish over the uneven road surfaces we have, but for track work is stiffer better!.
I have a lot of questions and in no particular order.
My current spring rates are (80f, 105r) most Lotus Trophy cars run stiffer springs, for example the 2Eleven GT4 spec is (105f, 130r) can some explain the dynamics of why if all things are equal these stiffer springs would be better/faster. I understand if you are on faster circuits you need stiffer springs with the higher aero effect pushing the car down more and this is why they come with damper adjustment but does a stiffer spring on a smooth surface equate to more grip than soft.
Does using slicks mean stiffer suspension required and if so why.
My very uneducated guess is that the suspension stiffness needs to be increased the faster you are going to keep the body roll and chassis flex to a minimum as the faster you go around a bend the more gravity and g-force try to do the opposite of this, thus reducing tyre contact patch. Am I on the right track with this thought or am I not understanding how it works.
Am I right in thinking the stiffer your set up, the less warning you get of the tyre grip braking away.
Would too stiff promote under steer or is that down to the balance between front and back grip.
Would the same car need tyre pressure adjustment on track if you came into the pits and changed out the springs for a higher rated set.
I read somewhere that In the Nitron range all the dampers and valving are the same, it is just different spring rates that change to cover their model range. Would I be right in thinking this would be why their top spec ones NTR race would need reconditioning sooner than the fast road ones, because the valving is working harder to control the stiffer spring.
Thanks in advance for any enlightenment on the subject.
Was having a think about the OPs spring rate questions.
For starters I would add that I don’t know any of this with any amount of authority!
For just about any application that requires a spring there’s a theoretically perfect spring rate. Most cars as standard are relativlely softly sprung, so stiffening the springs will usually improve grip. Stiffening the spring beyond that ‘perfect rate’ will then make things worse. The balance and interaction between front and rear are what affects understeer/oversteer.
Some slicks/race tyres usually benefit from stiffer spring because they are able to generate more grip and subsequently transfer more load into the suspension, without stiffer springs the damper could bottom out or the spring could go coil bound which if stiffer was always better would be the ultimate in grip wouldn’t it?! We all know that this isn’t the case.
Body roll is not the enemy of grip as long as it’s accounted for in the suspension geometry to allow the tyre contact patch to do it’s job. S1s on the old yellow Konis used to roll around a bit but I can’t say they lacked much in the way of grip. I also don’t think stiffly set up cars necessarily give you any less warning on breakaway, but any associated increased grip levels will mean that there’s more ‘energy in the system’ when things eventually let go.
Not sure on the tyre pressure versus change of springs, but I would expect so as you’re altering the wheel rate.
A question for the question now - Do the Nitrons have the exact same physical valving or just display a similar plot shape on a force/velocity curve? The plot shape is more dictated by the ratio between bump and rebound adjustment, but actual values can be very different.
All other things being equal damping higher rate springs generates more heat and makes the damper oil suffer more, meaning shorter service intervals.
Hope some of that makes the waters slightly less muddy.
) can be a disadvantage!, I can understand this for road driving as it would get skittish over the uneven road surfaces we have, but for track work is stiffer better!.
