Torsional what?
I’ve just read Georg’s first First Drive of the BMW M240i in your January 2022 edition.
I am bewildered (happens regularly these days) by Georg’s statement: ‘On the credit side… the improved torsional stability… dramatically reduced axle lift (up by 50 per cent)…’
Please explain ‘torsional stability’ and ‘axle lift’, and surely a reduction in whatever axle lift is would cause a 50 per cent reduction rather than increase.
By ‘torsional stability’, does Georg mean torsional stiffness? And does this increased torsional stiffness reduce the unwanted chassis deflection that causes wheels to lift (as per the Lotus Cortina)? Bill Pack
Right, Bill, let’s have a crack at this. You’re right: we/he meant torsional rigidity, and the missing keyword – ‘stiffness’ – was lost in translation. Every new car comes with an enormous and barely credible increase in torsional rigidity and yes, it’s obviously a good thing: more consistent suspension geometry/ chassis behaviour; better feedback for the driver. Axle lift is obviously a bad thing but you’re right – another outlandish press kit percentage devoid of context. But Georg isn’t wrong, and when you look at the new car it’s undoubtedly a more serious device than the previous car aerodynamically, with a lower nose, deeper splitter and more intricate vents. For most people this all just makes the car look cooler. But for Georg, who travels Germany at the kind of speeds most people experience only in a plane, reduced axle lift is highly desirable. BM