Much has been said about which is the more superior transmission in a car: manual or automatic. Just to confuse things, there has been an infusion of fence-sitting pretenders, like semi-automatic, Tiptronic, sequential manual and the weird CVT (Continuously Variable Transmission), which fall in the wide gap between fully manual and fully automatic power trains.
While it might seem difficult to place the call on which outranks the other, it is easier to break the argument into four separate sections from which judgment can be made: mode of operation, driveability/usability, performance and economy.
Mode of operation
The transmission of power in a car starts from the engine, which is mated to a flywheel —a heavy, toothed metal disc that acts as part of the starter system. The starter is engaged to this flywheel, which then turns the engine every time it is cranked.
The flywheel also damps engine vibrations for increased smoothness. Onto this flywheel is bolted a clutch, which is then connected to the vehicle gearbox. The difference between manual and automatic gearboxes starts from the clutch.
Manuals always use a friction clutch, while automatics use either an electronically operated friction clutch or a fluid clutch, also called a torque converter (these clutches will be explained in a later article).
The gearbox layout is the next big difference between these two transmission types. Manuals use constant mesh gears, sometimes with synchroniser assistance, while automatics have epicyclical gears.
So, how is a manual gearbox operated? The driver is supplied with three foot pedals: the throttle/accelerator pedal, the brake pedal and the clutch pedal. The clutch is the one we are most interested in.
When taking off, with the engine running, the driver is required to depress the clutch pedal, shift the gear lever into first (commonly called Gear One), then throttle up slightly while slowly releasing the clutch pedal.
At the biting point (the point where the engine power starts being channelled into the gearbox via the clutch), the driver releases the parking brake (commonly referred to as the handbrake) and motion is achieved.
As the engine revs rise, one is required to gear up, done by taking the right foot off the throttle, fully depressing the clutch pedal with the left foot, engaging the second gear with the lever, then releasing the clutch pedal while throttling up again.
This is repeated until the top gear is reached. Gearing down is done pretty much the same way.
Things are a lot simpler with an automatic. The gearbox has four distinct positions: P (Park), R (Reverse), N (Neutral) and D (Drive).
Taking off simply means sliding the gear lever into D, disengaging the parking brake and flooring the throttle. All the clutching and declutching is done for you, as is the case with gear changes, hence the label automatic.
Driveability/Usability
As explained above, driving an auto is dead simple. In D, acceleration is simply achieved by increasing pressure on the accelerator pedal, while slowing and stopping only requires a firm shove of the brake pedal.
With a manual, things are a little bit more involved than that. Downshifts and upshifts require clutch control by the driver, while a dead stop will call for further clutch control.
Clutch control involves clutching, declutching and “balancing” (most drivers should be familiar with this term). So it looks like an auto is much simpler to drive than a manual.
But is it necessarily better? Those that had a rough time with clutch control back at the driving school will raise their hands shouting “Aye!”, but there are more than a few naysayers around, myself included.
Simpler is not necessarily better, especially when we introduce the concept of driving pleasure. Driving an auto is boring, to summarise things. Movement is centred on the throttle and brake only. The autobox robs the driver of a sense of control.
The experience from behind the wheel is bland, to say the least, and on long trips, soporific.
Driving enthusiasts say there is no better feeling than depressing the clutch with your left foot and selecting the gears yourself through the gratuitous H-gate; simplicity be damned.
Hill starts are also a bit of a challenge, and nobody can claim they dislike a challenge — look at the number of people, drivers included, that rush to fill Sudoku grids in our local dailies. Is that not a challenge?
The counter-argument is this: The pleasant sensations of clutching, declutching and selecting gears are best enjoyed on an open road.
When trapped in the worst of Nairobi’s gridlock, it becomes a pain, a heavy cross to bear, more so if you are trapped on an uphill stretch.
Summary? Automatics are for beginners, the inept and city-dwellers. Manuals are for the discerning autophiliac, the true petrol head.
What group do you fall in?
Performance
Sharpen your swords everyone, for here we put paid to a long-standing fallacy. Manuals are always quicker and faster than automatics, given that everything else is kept constant.
Those that claim otherwise do not know how to get the best out of their manual transmissions (see Driving an Auto Vs. Driving a Manual, coming soon). The reason behind this lies in the clutch mechanism and the gear ratios chosen for each transmission.
As explained earlier, most automatics use a fluid clutch. The power losses involved are markedly higher than those of a friction clutch (with zero per cent loss if the mechanism is in good working order) as seen in manual transmissions.
Therefore, the power channelled to the wheels via the torque converter is only a fraction of that out of the engine, meaning stunted performance. Not so with a friction clutch.
The gear ratios also determine performance. Because of the power-sapping torque converter, automatics are equipped with tall gears (slow acceleration to maximise on speed). Some slush-matics have boxes geared for 100KPH in 1st.
Fancy, yes, but acceleration is pathetic. Automatics also tend to have fewer gears: four is the norm, while freaks like the Dodge Neon have only two or three. Manual gearboxes typically have four, five or six.
More gears means less spacing between the gears, meaning the engine revs can be maintained at peak power levels without long stretches of revving up in between. Performance-wise, manuals take the cake, without exception.
Economy
Economy is not just fuel economy; it is the general pocket-friendliness of the car. Any driver that has ruined his automatic transmission will tell you (tearfully) of the hole he burnt (or is still burning) in his wallet trying to get it fixed or replaced.
While fixing a manual box is not exactly a holiday in the Maldives, it is a lot less painful compared to an automatic.
You might be able to force an auto to downshift, but you cannot force it to shift up.
If your car decides that second gear is what is required to ascend that slope, while you in your infinite wisdom clearly know that third has enough torque to do the job, there is little you can do to have your way.
In a best-of-three contest, the manual transmission takes two: economy and performance. Driveability is a 50:50 affair; subject to the individual and prevailing circumstances.
Where does your vote lie?
