Roll stiffness affecting Steering Effort .

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Discussion Overview

The discussion revolves around the impact of roll stiffness on steering effort in a touring car, particularly after modifications to the front suspension geometry. Participants explore the relationship between roll stiffness, steering dynamics, and driver feedback during cornering.

Discussion Character

  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant inquires how increased roll stiffness might lead to greater steering effort, suggesting it could relate to lateral load effects or tire deformation.
  • Another participant asks for clarification on the specific changes made to the car's suspension and its behavior during different phases of a turn.
  • A participant describes modifications made to the front suspension, including adjustments to the roll center and its effects on roll moment and stiffness without altering spring stiffness.
  • Concerns are raised about the implications of raising the roll center, with one participant arguing that it reduces weight on the front tires during turns and increases camber build, potentially contributing to the driver's increased steering effort.

Areas of Agreement / Disagreement

Participants express differing views on the effects of roll center height and roll stiffness on steering dynamics. There is no consensus on the best approach to mitigate the increased steering effort reported by the driver.

Contextual Notes

Participants discuss the implications of suspension geometry changes, but there are unresolved assumptions regarding the specific effects of roll center height and its relationship to steering effort. The discussion lacks detailed mathematical analysis of the changes made.

Who May Find This Useful

Individuals interested in automotive engineering, particularly those focused on suspension design and vehicle dynamics in motorsport contexts.

satya430
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I am currently working for a Touring Car Team . I have modified the front suspension geometry . Made the roll moment lesser and increased the Roll stiffness . Driver complained that the steering effort has increased considerably in the corners .

1.How does increased roll stiffness increase steering effort ? Does it have anything to do with the lateral load due to diff geometries pushing the tire down or giving it a more of a tire wall deformation effect ?

2.What are the methods to reduce steering effort other than
a.Reducing the scrub radius .
b.Increasing the knuckle moment (very difficult as it changes the steering geometry) .
c. Simply giving him a bigger steering wheel .
 
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what exactly did you do? what is the car doing at turn entry, middle and turn exit?
 
I am working to change the stock suspension of a touring car (Mc Pherson Strut)
The front suspension geometry is being changed (the question above is about the new front geometry) . I have brought the front roll center of the car closer to the front Center of Mass(or mass centroid as referred to as in many books) . This has decreased the effective roll moment and thus increased my roll stiffness of the front without having to stiffen my springs .
Now as I have kept the new control arm ball joint in the same position of the old one , the KPI and scrub radius shouldn't have changed . As the driver complains that steering needs more effort now , what could have caused it .
The car trail brakes at the entry (dive-wt transfer to the front and roll-wt transfer to the outer ) . It kisses the apex (ideal condition) and then accelerates out of the corner . Pl. tell me if I am wrong .
 
i sure dfo believe the driver now has a handful driving..when you rasie the roll center it shortens the lever arm and you have a lot less weight being planted on the front tire in a turn. Plus you increase camber build
i am not a big fan of high RC..the lower, the better
 

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