ISSUE 2014 MAY/JUNE
Spin doctor – GYROSCOPIC EFFECTS ARE A CRUCIAL CONSIDERATION FOR CANCELLING OUT DESTABILIZING CHARACTERISTICS IN A SUSPENSION SYSTEM, SAYS John Miles http://viewer.zmags.com/publication/94a982b8#/94a982b8/34
ISSUE 2013 JUNE / On the job # John Miles ¤ Winter games
The whole experience reminded me of the lessons learned from driving with Magnus Roland in a prototype Saab 9000 compared against the first ‘aero’ Audi 100, back in the early 1980s. Boring to repeat, but the Saab was in another class for balance and controllability on the loose gravel. Roland and the dynamics understanding that flowed from Saab rally-car programs showed that in conditions of extremely low grip, anti-roll bars and spring rates have little effect on handling, because there is insufficient weight transfer to modify tire loadings; and that it is wheel steer that has the biggest effect, especially compliance steer, and to a lesser extent kinematic steer. That was more than 30 years ago, and I can’t think of any situation I have experienced where that has not proved to be the case.
ISSUE 2011 JUNE / On the job # John Miles / Reverse logic – Magnus Roland’s rear suspension philosophy impresses John Miles
Chassis guru Magnus Roland’s history with Saab, GM, and now his consultancy S2AB continues to be all about a missionary zeal and passion, in the field of vehicle dynamics, particularly in relation to rear suspension topology and kinematics. To put it bluntly, he wants to turn accepted thinking on its head, his ethos depending (as it always has) on the philosophy of ‘reversed kinematic steer’ at the rear axle; that is to say bump steer trajectories that tend toward slight toe-out, whereas the accepted norm is that a rear axle must toe-in with bump or lateral force, since it is claimed that this is the only way to inhibit yaw gain, and provide adequate lateral acceleration response at the rear axle.