- We explain how automatics work
- What is a DSG and a CVT?
- Which is best for you...
The main difference between an automatic car and a manual car is that the driver of a manual car presses a peddle (the clutch) while manually changing the gears, using a gear-stick. Automatic cars change gears too, although they do it automatically. A manual car also has three pedals - the brake, the accelerator, and the clutch whereas an automatic just has two - the brake and the accelerator.
There was a time when even if you wanted an automatic gearbox they weren’t always available. Automatic cars were pretty much exclusive for buyers of posh executive cruisers. In contrast, owners of smaller motors had to learn how to change gears themselves, these are known as manual cars.
How times change. Now you can buy pretty much any model with a choice of automatic, manual or combined gearbox. With that in mind, what are the major differences between manual and automatic geared cars?
Manual vs automatic
The biggest difference between the two is that with a manual you change the gears yourself. With an automatic, the car does it for you.
Rather than pushing in a clutch pedal and moving a stick to change gears, as you do in a manual, automatics just have a brake and accelerator. To start off, you move the lever from P (Park), past R (Reverse) and N (Neutral), into D (for Drive).
Cars with manual gearboxes usually have a maximum of six forward gears. Automatics have up to nine. As a result of this, automatics can change into the most suitable gear for the current driving conditions. This makes some cars slightly more economical than manuals.
Most automatic cars now also let the driver change gears themselves, either by pushing the gear stick or with switch-like paddles on the steering wheel.
To do this, automatics need a lot of development and high-tech parts, so they are often more expensive to run than manual cars.
How do automatic cars work?
That depends on the automatic car you’re talking about. There are various sorts of automatic gearbox, some very good, some not so great.
The key to a good auto is that it should change gears smoothly when the driver needs it to. And different car manufacturers have different methods on how to do that.
What is a traditional automatic gearbox?
The traditional auto is called a torque converter by car experts. This uses a fluid coupling between the engine and gearbox to transmit the power.
In its early days, more than half a century ago, the gear changes on traditional autos could feel slow although still smooth. But with development and the clever use of electronics, there are now some brilliant torque converter gearboxes available on motors such as BMWs, Land Rovers and Jaguars.
What is a semi-automatic gearbox?
These are also known as robotised manuals, clutchless manuals or automated manuals. They are a manual gearbox with the clutch pedal removed as the car does that bit of the process for you.
This is one of the cheaper ways of making an automatic car. The technology is lightweight and simple to engineer, so small cars that are sold with automatic gearboxes often use this system.
The downside is gear changes can often feel clunky, especially at low speeds around town.
What is a DSG gearbox?
DSG stands for Direct Shift Gearbox. It’s actually the name given to this type of gearbox by the Volkswagen Group but as theirs was the first it’s caught on and is now widely used.
A more correct name is the double clutch gearbox, but in fact, this is a bit like two gearboxes in one.
The thinking behind it is that it’s quicker to change input shafts between the engine and gearbox than it is to swap gear cogs. So the DSG uses two clutches.
One works with odd number gears, one with even. When you are in first gear, second is primed and ready. Change to second, third is primed and so on. The big advantage is changes can be lightning fast and super smooth at speed.
What is a CVT gearbox?
This stands for Continuously Variable Transmission and actually isn’t a gearbox at all. It’s easiest to imagine a rubber band between two pulleys. The ratio between these varies constantly depending on vehicle speed, engine speed and whether the driver is accelerating or braking.
As the CVT should always be in the correct ratio for the driving conditions, these gearboxes are economical. They’re also simple and cheap to maintain. But the CVT isn’t for keen drivers. When you accelerate hard it can feel like a regular gearbox with a slipping clutch. The engine is roaring away but you’re not getting anywhere as the pulleys struggle to keep up.
Manual or automatic - which is best?
This depends on the car, the automatic gearbox and the type of miles you do. If you spend a lot of time in traffic or you simply can’t be bothered changing gear, then a good auto is for you.
Most have a manual option as well, should you ever wish to change gears. And the electronics that control automatics are now so advanced, you rarely ever find yourself in the wrong gear.
But if you’re after a small car and the choice is between semi automatic or CVT and a manual, you might well prefer gear changing yourself.
Whether you choose a manual or automatic car also depends on your attitude to driving. If you’re a keen driver, you’ll enjoy changing gear yourself. It gives you greater control of the car and makes you feel more connected to the driving experience.
And you might become frustrated with the quirks of some semi autos and CVTs, then again you might prefer to change gears yourself.
If you’re concerned about repair bills, there’s unlikely to be much in it. Automatics are more complicated with more parts and electronics to go wrong. When they do go on the blink, they can be expensive to fix. That’s not to say that a manual won’t need repairing one day, but that’s more down to age and potentially poor driving techniques.xx
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