Hi Jack, thanks for the comment. Yes for point 1, the damper is no longer working through the centre section and in most cases, wheel lift will not occur on the driven axle, therefore the anti-roll bar is still very much in control of the cornering behavior through the apex section and can be used to control oversteer/undertseer characteristics.

With regards to point 2, we are describing two scenarios at opposite ends of the spectrum that have the same results. Therefore it is really important to diagnose where your car lies on the spectrum of roll stiffness so you can adjust it correctly. In a nutshell, most cars out on track are already stiff enough and do not roll excessively through the corners therefore the first lot of methods can be used to tune the roll bars, where we mention “which is n answer that will usually be given across most competitive motorsports where the suspension set up is designed with particular spring rates and stiff suspension set ups”. However, if your car is a passenger car with soft suspension and it rolls a lot through corners then first you need to stiffen up the suspension as the excessive roll will be causing you the issues so they need addressing in the exact opposite way. Due to our articles having to apply to as many scenarios as possible we need to include both methods but we rely on the the reader to know where their car sits on that scale.

Finally, we do not provide example rates as every car is so different with different roll centres, installation ratios, tyres, COG heights, vehicle mass, mass distribution, application, unsprung mass and much more that it is not possible to provide a blanket bench mark figure as that doesn’t begin to touch on driver preference and feel which alters the figures again. It is a complex process to calculate your ideal spring rates (something well worth doing) and we have some articles that walk through the equations required to achieve this too.

Thanks

You make reference to roll causing the understeer but then the above 2 situations still appear to contradict each other ? What am I missing ?

And lastly I appreciate your effort to keep the articles short and simple but the one common thing among all articles is (and the bit most everyone is looking for) no one is willing to give some starting figures of spring rate, shock absorber setting and anti-roll bar stiffness based on sprung and unsprung corner weights for example ? Do you have access to such info that you’d share ?

Many thanks in advance. Jack

Hi Christo, if your car is far too soft then stiffening the roll bars will help to reduce understeer as it is the amount of roll causing he understeer to happen. If you car is relatively stiff and it is understeering then you will need to soften the front roll bar to reduce understeer so it is identifying whether the car is far too soft at the moment or not.

Hi Peter, The resistance from the bushing can be considered negligible in comparison to the anti roll bar stiffness. A good bush that is well lubricated should only house the anti roll bar and should allow the bar to rotate freely within therefore not adding to the stiffness or resistance. Thanks

So stiffening the front roll bar is the solution? Everybody suggests the other way around.

Can you please clarify?

Thanks.

Hi Phillip,

Thanks for the comment. G is the torsional modulus of rigidity of a material whereas E is the Young’s modulus which have different values. An example of G is cold rolled steel has 79 GPa as it’s G value.

Thanks

Hi, we have now updated the post to include blade style cantilevers. However, some assumptions need to be made as we have explained in the post to prevent the calculations becoming extremely complex.

Thanks

Hi Lukasz, Thank you for bringing our attention to that equation. We have now rectified the misplacement of a power and the equation works perfectly.

Many Thanks
Suspension Secrets