Drive trains: 4 wheel drive, all-wheel drive, front wheel drive and rear wheel drive
When it comes to choosing the right car, the amount of jargon involved in models, specs and extras can drive you bonkers!
As part of that, we tend to see that customers don’t really know whether they need, (or even want) 4-wheel drive, and the difference between front and rear wheel drive isn’t well known either.
In a bid to help the confused consumer, we’ve popped a few facts together about drivetrains to help you out.
Before we begin
We’ve got a few phrases that will be handy to know before you dive headfirst into the article:
A differential is a mechanical device that makes the wheels turn. The position of the differential is what makes vehicles 4-wheel drive, 2-wheel drive, as well as front or rear wheel drive!
Traction is the term for the grip between the wheel and the road.
Torque is the power that the wheel is given to make it turn.
FWD vs RWD
Most of the cars on the market are either front or rear wheel drive, and since most of the population likely to own one of these, you should find out which one is best for you.
Front wheel drive (FWD)
The front wheel drive setup tends to be the cheapest to build. This is because the transmission doesn’t have to be separate from the engine so it can be built into the same unit. Thanks to this, the vehicle will be lighter which is better for fuel economy.
Since the weight of both the differential and the engine will be over the front wheels, you’ll have improved grip when pulling away in adverse weather conditions (it’s worth noting that this isn’t as impressive as a 4 wheel drive car.)
If you are going to accelerate on a dry surface, then front wheel drive won’t have as much traction when compared with rear wheel drive. This is because acceleration shifts weight backwards, so there won’t be as much downforce over the front 2 wheels where the power is. This results in slightly slower acceleration from front wheel drive cars.
If you’re penny conscious, it is worth noting that the front tyres can wear quite quickly. This is because they will be doing the most work whilst under a lot of weight during normal driving.
The Fiat 500 is a front wheel drive car
Rear wheel drive (RWD)
Rear wheel drive is more common in luxury and sports cars, this is mainly due to the fact that RWD has better acceleration compared to FWD. It works the same way, but the extra weight is pushed over the rear wheels where the differential is and in turn, produces more grip.
Rear wheel drive lets the side down when it comes to handling in bad weather. RWD vehicles have a high chance of wheel-spinning or fishtailing when the roads are slippery. This is because the driving wheels at the back have less weight over them when driving normally compared to FWD, which results in less traction on the road in snow and ice.
But it’s not all bad. The possibility of fish-tailing is a favourite with petrol heads as it means they can drift a lot easier!
4WD vs AWD
Generally, there isn’t a lot of difference between 4-wheel drive and all-wheel drive. But the fundamentals are important when it comes to making a decision between the two.
(Now, this gets pretty complicated, but we’ll try our best!)
4-wheel drive (4WD)
Modern 4 wheel drive cars have the option to drive in 4WD or 2WD, (this can be called full or part-time.) If you choose full-time 4WD, power will be sent to all 4 wheels equally whereas in part-time, the power can be sent to just the front or just the back wheels, basically resulting in front or rear wheel drive.
If you opt for full-time 4WD, you’ll have better traction as all 4 wheels are being sent power and they will therefore all have torque. This makes it more likely for at least one tyre to get traction which is why 4WD is ideal for climbing steep, uneven and slippery surfaces.
The Land Rover Freelander has 4-wheel drive
All-wheel drive (AWD)
Like 4 wheel drive, you can change all-wheel drive from full to part-time. The difference between the two is all to do with the mechanics. In AWD, the wheels are all driven by differentials, so if necessary, all the engine power can be sent to any one of the wheels. 4WD is only able to split the power 50/50 between the front and back.
So AWD is pretty handy when you have low traction. Imagine if 3 of the wheels are spinning quicker than the 4th, this would suggest that those 3 wheels have less grip, so the power can be sent to the 4th wheel with the most traction.
4 wheel drive tends to be seen on traditional off-road vehicles like Land Rover Defenders and even the Ford Ranger. You’ll see all-wheel drive in more modern SUV’s, luxury brands and sports cars. But this isn’t a definite distinction, and the lines are pretty blurred between the two.
When it comes to the benefits of 4WD and AWD, it’s hard to tell the two apart. They have the ability to send torque to all 4 wheels of a vehicle which increases traction and is better for treacherous conditions.
But when it comes to buying a car, you may want to consider whether you tackle such bad weather conditions enough to warrant AWD or 4WD.
On top of that, it’s worth keeping in mind that the complex mechanics make AWD and 4WD vehicles more expensive to buy and heavier too, so your MPG can be affected. So, if you’re looking to save a few pennies then FWD or RWD will do you well.
But if you want better handling and confidence in bad weather, then go for a 4-wheel drive or all-wheel drive motor.
Why not try these drive trains out yourself? Visit one of our showrooms and really get to know the difference on a test drive by calling 0808 250 3692.