Re: Calculating your cornering G force

Messy.

You know you are having fun when inanimate objects in the car become excitedly animate. I've had stuff placed on pass seat bounce off side glass and even sunroof before I've batted them down into pass footwell.

The formula is a mathematical constant but at low speeds it only takes a small numerical error in speed or radius to make a large difference in the result. 32 mph would be 0.9g and 31 mph 0.85g. Speedos usually have a larger percentage inaccuracy at low speeds than high. Mine for instance is doing a true 26.8 mph at indicated 30 (11.7% error), true 36.4 at ind 40 (9.8% error) and settles to about 6% fast above 70 mph. In fact the error is closer to a constant 4 mph than to a percentage until it reaches high speeds.

Unless you've calibrated the speedo at the speeds you are actually cornering at the results are too imprecise to be relied on.

The effects of camber mean ploughing through a lot of rather unpleasant equations. I've just spent the last hour doing that and at the sort of grip levels normal cars experience every incremental 1 degree of camber increases the potential speed of the car by about 1.8%. So a 5 degree camber would increase the potential speed by 1.018^5 = 1.093. A 31 mph curve would become a 33.9 mph one.

This relationship stays fairly linear up to cambers of about 25 degrees so more than enough for anything you'd see on a public road.

If you add the one or two possible mph speedo error to the few mph possible camber error you can obtain G forces varying by a huge amount. You need to try the experiment at higher speeds and in the range your speedo has been calibrated at.

You need to survey the curve with a sprit level to find the camber. If you wind up as road kill it's not my fault.

Any slight grade will change it too. Unless it's dead flat you are effectively accelerating or decelerating which changes the traction available for cornering.