Hey Guys,

The number's speaks for themselves,

*Moment arm from tyre to c.g 800mm - 1500mm depending on the car.
*Self aligning torque moment arm in the tyres are in the order of 20mm - 50mm. Also this bleeds off as we hit peak slip angle.

Self aligning torque can be visualised as a result of the lateral force applying a moment arm about the centre of the contact patch. Consequently when you do the numbers for the static margin it's effectively swamped by the moment arm of the axle to the c.g. Also this moment arm bleeds off as we hit peak slip angle.

Consequently in terms of car handling and static margins it's a mild second order effect. However it makes its presence felt in the torque the driver feels through the steering wheel. This is where the good drivers earn their money.

However guys - work through the example I presented above in my previous post. To really ram home the point calculate the typical contact patch length for a given load, tyre pressure and area. The conclusions are pretty obvious.

Enjoy

Danny Nowlan
Director
ChassisSim Technologies