Cornering Flat Out

[d3vine]

I've noticed when an Ultima GTR corners, it leans left/right. How exactly can you setup the car to corner flat? Do you use stiffer springs, anti-roll bars?

[Sam_68]

Yes, you use stiffer springs/anti roll bars.

But both have unwanted side-effects.

Th only other solution (without fitting actve suspension) is to alter the suspension geometry so that the roll axis coincides with the CG, but again, that would have serious side effects.

[d3vine]

What are the side effects if using stiffer springs/anti-roll bars?

[tim the pool man]

In the real world, you will lose grip once you exceed the optimal spring/roll stiffness. Especially on the road as opposed to a smooth racetrack.

In fact, (and very simpified I know...) if you are tuning a car's handling, you will soften the end that needs more grip ( eg if it is understeering you would soften the front bar or stiffen the rear)

[Sam_68]

^^^What Tim said.

There can be other, more subtle side-effects, too.

For example (to expand a little on Tim's comments) different spring and ARB rates are used to manage diagonal weight transfer across the car when cornering, which in turn influences understeer/oversteer characteristics. Not usually a problem if you increase the stiffness of everything in the same proportion, but even then, it can occasionally have unforseen effects.

Also, very stiff anti-roll bars are sometimes jokingly referred to as 'beam axle conversion kits' ...only half in jest! With any anti roll bar, the shock of a bump at one wheel is transmitted to the opposite wheel, effectively trying to lift it off the tarmac. With a very stiff ARB, this effect can actually be much worse than the similar effect experienced by beam axles.

Plus, anti roll-bars are not individually damped, so if you fit a very stiff ARB, you need to either increase the damping of the main springs (which can then leave them over-damped for normal bump/droop), or run the risk of what is referred to as 'roll rock'; basically the car 'bouncing' laterally on the un-damped spring of the ARB.