Ok, to me the layman;
Traction; The cars tyres spin less and more power is used propelling the car foward.
Grip; When cornering the more grip you have the less the tyres will slip sideways.
Now I read car magazines a lot and I’ve picked up the following wisdom, front wheel drive cars have poorer traction than rear drive cars hence performance cars have rear wheel drive eg Mercs BMWs etc. How so, if the engine is over the driven wheels wouldn’t fwd have better traction? Isn’t that why rwd cars rear end lose grip under slippy conditions sooner than fwd cars?
Does this mean 4wd cars have both superior grip and traction.
When a car is cornering and accelerating I’ve seen descriptions of the rear or front end being “loaded” up and with it levels of grip varying, is there a laymans way of explaining.
No simple answer to that question that is also correct. There are some safe generalizations but those depend on many factors other than those listed.
Front wheel drive is at a disadvantage in straight line acceleration because of weight transfer to the back wheels. Note I said weight, not mass. A car does not accelerate with a rocket engine pushing in line with it’s center of mass but with rotating wheels well below it. Rear wheel drive makes a better dragster becaus the weight shift maximizes drive wheel traction.
Front wheel drive can be at a disadvantage in cornerering because of too much weight on the drive/steering wheels. A large amount of the weight and side load from the turn end up on the front outside tire, often overloading it. The side loads can deform the profile affecting the contact patch. In steady state cornerering the car will often “pushy” with the front wheels sliding. Front wheel drive cars require very different driving techniques than rear wheel drive cars.
Driving in snow is a completely different matter than high performance driving on dry pavement. Front wheel drive cars usually excel in this as they have good drive and steering traction under moderate driving loads.
Ther are wild exceptions to those generalizations. When I was driving slaloms in in the early '80s the most consistently fast driver had a '78 Volkswagen Rabbit with a stock engine. Naturally it had full race tirs and the suspension from hell but the drivetrain and suspension geometry was no different than the stock rabbit. I can’t remember ever seeing anyone beat him on a tight slalom course no matter what kind of car. Drivers with Porsche 930s, Ferraris and open wheel formual race cars couldn’t touch him.
The following is not exactly the question that the OP asked, but it is interesting to the discussion:
I will say that either FWD or AWD are the most “unsurprising” drivetrain configurations.
When turning in a low traction situation, heavy throttle in a RWD car can cause the rear end to lost traction. This will make the vehicle oversteer… that is, it will steer too much, and if it happens dramatically enough, you’ll wind up pointing straight towards the inside of your corner, rather than down the road.
That can be weird, and scary, to an inexperienced driver.
When turning in a low traction situation, heavy throttle in a FWD car will usually just make you “understeer”… it will “go straight” instead of turning as you’ve directed it to do using the steering wheel. This is much less scary than oversteer.
I’m guessing enough gas in a powerful AWD car would cause 4 wheel drift, but I’m also guessing that most AWD vehicles don’t have enough juice to do that.
