How to deal with understeer and oversteer
Tuesday, 27 August 2019
In these days of sophisticated electronic aids to help keep cars - and drivers - on the straight and narrow, the terms understeer and oversteer may appear a little worn.
Yet both these motoring dynamics remain with us in varying degrees and can result in accidents, big or small.
Essentially understeer is when the car doesn’t turn the corner until it’s too late.
And you’re off in the weeds on the outside of the turn.
Oversteer is where the car attacks the corner before the vehicle nears the apex of the turn and the back slides out.
Now you’re off in the weeds on the inside of the corner.
North American racers call understeer ‘push’ - the car is pushing you straight, off the road.
To them, oversteer is ‘loose’ - where the rear end has lost its marbles and is coming around to overtake the front.
True, there are any number of traction and stability aids today to help prevent these scares, but few cars or drivers are infallible.
Understeer will push the car to the outside of the corner and, often, right off the road.
This happens when front tyres - because of too much speed, heavy braking or too much steering lock - lose traction and won’t respond to a driver’s steering inputs.
The result is a car sliding straight on, refusing to be turned.
In general, cars today are more likely to understeer because most are front-wheel drive and much - traction, steering and braking - is asked of front tyres.
Remember, wet or muddy roads will exacerbate this problem.
What to do with understeer
Slow down, steady up if a car understeers but don’t be abrupt with throttle or brakes.
Back off the angle of the steering a tad to give front tyres a better chance to regain grip.
Be considerate but firm with commands through pedals and steering wheel.
Try and read turns ahead - slower and smoother into a corner will mean a smoother, better-balanced exit.
Oversteer is when rear tyres lose grip and swing the tail off line.
This could be, as with understeer, the result of too much speed, too much brake as you turn in or backing off the power abruptly.
Any of these can upset rear tyre grip and the car’s balance as it is steered into the corner.
The car heads toward the inside of the corner before the turn is finished - it steers further, or ‘over steers’ - from what the driver wanted.
Rear-drive cars are more prone to oversteer.
What to do with oversteer
Stay cool, back off the accelerator a little - but don’t jump off abruptly - and keep steering where you want to go.
You could try ‘tickling’ the throttle to get the car’s momentum back under control.
Good drivers, in rear-drive machines, can balance oversteer into a four-wheel drift, sliding sideways through turns.
For most drivers best try that on a skid pan.
Understeer or oversteer can be controlled to some extent through driver or electronic inputs (leave those stability controls on) but just as important are good tyres.
Tyre treads need a safe depth for maximum road grip and front-end wheel alignments also help keep cars on the right track.
Book in for a check-up with a workshop on AutoGuru for safety’s sake.
Bruce McMahon is a Queensland-based journalist who’s spent a fair slice of his career dealing with automotive matters.
His first car was a 1949 Riley Roadster, followed by a mix of machinery from Porsches to Jeeps, Alfa Romeos and Range Rovers through to the current four-wheel drive Mazda ute.
He’s driven the Nurburgring and the Tanami Tracks.