A non-driver asks...

[Lie-in King]

...Despite never having driven (unless 1 easy lesson counts?..), I really enjoy watching Top Gear, but no-one I've asked has been able to explain - in "idiot-proof" terms! - what is meant by "under & over-steer".

I've tried to spot what they mean, but I'm afraid it keeps eluding me - obviously with no driving experience, I'm at a disadvantage, so can someone please put this pedestrian petrol-head out of his misery?

Thanks for your time & attention!

[naughtyboy]

Under-steer is more typical with front wheel drive cars,what it means is that when cornering hard the car tends to want to go straight on instead of where you steer it. Over-steer is where you steer hard into a corner and the car turns too sharply into a bend e.g. the rear end of the car starts to want to drift out, this is more typical of rear wheel drive cars.

[R1Geezer]

Naughtyboy is correct. To help you further though, think of it like this. take any vehicle 4 wheels with the front wheel doing the steering. Now move slowly and when the wheels are turned the car turns according to how much the steering wheel is turned, so it is neutral ie you can control the direction by moving the wheel the corresponding amount. Now speed the whole thing up and imagine turning left but because the tryres are not totally gripping the road some of the left turn is not happenning ie the car is trying to go straight on so you get some left and some straight on, that is Under steer, ie the car is not steering as much as it should for that amount of steering input.

Oversteer is also caused by speed but what is happenning is the front is steering correctly but due to other factors the back tyres are not gripping and are breaking away hence the back end tries to go out to the right so the car is turning more than it should for the steering input, ie oversteer.

Geddit?

[Lie-in King]

With apologies for the late reply, my sincere thanks for the helpful answers, guys! Now I see it... :-))

...I hope one of you sees this reply & can then help with a follow-up?

Does 4-wheel drive therefore stop it happening, or is that too simplistic?

Sorry to be an ignorant pain, but I'm genuinely interested!

[R1Geezer]

4 wheel drive generally reduces the likleyhood of either but in reality the overiding factor here is physics and that is dependent on what the car is doing. so if you are turning left at 50mph, if the back wheels are still putting power down the ar5se end will want to come out, oversteer. if you've lifted off the power then the car will have a tendecy to want to go straight on, some of the input will turn it to the left but it will still trying and go straight on hence under steer.

Bottom line is that it's a driving phenomenon that can be surpressed or enhanced by certain characteristics of the car and how it's being driven.