A six-speed is a kind of transmission. As cars have two types of transmissions–automatic and manual–a common question that people also ask is also how many gears, or speeds a transmission has. The resulting number refers to how many gears the transmission has. If a vehicle has a six-speed transmission, it means it has six forward gears.
A six-speed typically means a manual transmission that has six gears, but both automatic and manual vehicles can have six-speed transmissions. Even if you don’t feel the shifts in an automatic transmission, the car still has gears present, and many automatic transmissions come with six gears as standard.
What Is a Six-Speed Manual?
A six-speed manual is a lever mechanism that a driver needs to shift to accelerate in a manual transmission vehicle. Different gears can accelerate the car through a corresponding range of speeds. A driver needs to shift through each of the car’s gears to be able to accelerate from a standstill to their car’s top speed.
During the nineties, five-speed manuals were found in most vehicles. The first five gears would occupy all of the gear positions except the lowermost right, as that’s where the reverse is located. The six-speed transmission was introduced in models like the BMW 850i and Ferrari 456 in the 1990s, but they eventually became standard in many cars in the 2000s.
As a result of the sixth gear occupying the reverse position of the old five-speed, six-speed manuals typically moved the reverse gear next to the first gear. To protect drivers from accidentally switching into reverse, some vehicles require the driver to pull the bottom of the gear lever upwards to be able to move the lever to the far left where the reverse gear is located.
Do More Gears Equate to a Better Car?
As gears control how power is transferred to the wheels, having more gears in your car gives you several different advantages.
The main advantage of having more gears is that cars can be more fuel-efficient. To understand how having more gears correlates to being more fuel-efficient, you have to understand how gears affect engine load and engine RPM (revolutions per minute).
Engine RPM and Fuel Economy
The engine’s RPM affects how much power an engine can make and how fuel-efficient it is. Essentially, at high RPMs, the engine can produce the most power and is the least fuel-efficient. At low RPMs, the engine produces the least power and is the most efficient. Cars are typically most efficient where they can get just enough power to accelerate or maintain their intended speed while using the least engine RPMs.
This is the reason why automatic transmission cars don’t use up the entire rev range during acceleration unless the driver is flooring the throttle. The car’s automatic transmission can hasten or delay upshifts depending on how much throttle is applied. This is why cars tend to use more revs while accelerating compared to when the car is cruising along the highway. This is because the car upshifts further to reduce the car’s RPM. That said, cruising at the highest gear possible isn’t the goal, as shifting up prematurely when you don’t have enough speed could cause the engine to knock and stall, causing vibrations because it doesn’t have enough revs to produce power.
Long and Short Gearing
Cars have different gear ratios that can determine the speeds at which their gears can run. Short gearing refers to a kind of gear ratio where the gears are closer together. A driver who’s driving a car with short gearing will accelerate faster but will need to shift more often. This gearing can be found in cars with small engines or sports cars like the Mazda Miata.
Longer gearing, sometimes called tall gearing, refers to a gear ratio where a driver can achieve a lot of speed in just a single gear. However, tall gearing in a car can correlate to slower acceleration. This is why this kind of gearing can be found in cars with powerful engines like the Porsche 911.
Most cars have transmissions that balance these two kinds of gearings to achieve a good balance of fuel efficiency and acceleration.
Why Is Six-Speed the Standard?
A six-gear transmission is a good number of gears for a car. First to third gears are good for speeding away from stoplights and corners, while fourth to sixth gears are typically used to cruise at varying speeds. As the car’s cruising speed increases, the higher the gear you can cruise in and the more efficient your car will be.
Even as some car manufacturers are making transmission systems with eight to nine standard gears, some manufacturers like Mazda still retain a standard six-speed transmission.
Why Do Sports Cars and High-end Luxury Cars Have More Than Six Gears?
Simply adding a gear to transmissions to be able to get better fuel efficiency isn’t as simple as it sounds. Not all engines can run a tall seventh gear if it was added like an aftermarket upgrade. It takes a lot of research and development to be able to make a car’s transmission correlate to better numbers.
Since the six-gear transmission was first found on high-end luxury cars and sports cars in the first place, it’s only natural for the same high-end brands to incorporate these more advanced transmissions into their drivetrains.
Are More Gears the Future?
With cars like the LC500 sporting ten-gear automatic transmissions and carmakers like BMW and Mercedes making 8-gear and 9-gear transmissions the standard, it’s highly likely. More gears allow these cars to carry powerful engines that can still achieve good fuel economy.
The Development of Six-Speed Transmissions
Some early automatic transmissions just had two speeds, then speeds were added, lock up converters became a thing for fuel economy. But there has been some waffling on that. Overdrive transmissions went away from about 1970 to 1979, but they returned with the high cost of fuel (gas jumped from 40 cents to $1 a gallon in the fall of 1978).
In the 1960s, there were a lot of three-speed manual transmissions with the shifter on the column (called “3-on-the-tree”). Some of those had an overdrive range for each gear, which worked with a planetary gearset in the rear of the transmission that was activated by a solenoid that extended a lock to engage a cog on the planetary so that each gear had an additional range. Those were effectively six-speed transmissions.
When driving one of those, you’d take off in first gear, release the accelerator, the planetary would be engaged, and you’d get some more speed in that same gear working through the planetary. When you pressed the clutch, the planetary would release and you’d go to second gear and repeat that process all the way through to third gear with two ranges in each gear.
This was a tremendous help with fuel economy, because it kept the engine in the most efficient part of its power curve. In a word, that’s what all these additional gear ratios are about today.
Four speeds became the order of things, and then a fifth speed was added that actually spun the final drive faster than the engine. Automatic transmissions with overdrive and lockup converters would solidify the connection between the engine and the transmission input in addition to the gears provided by the transmission itself.
Six-speed transmissions became standard in vehicles during the 2000s, and now modern automatic transmission vehicles can even make use of up to 10 gears in their transmissions. However, 8-speed, 9-speed, and 10-speed transmissions are only exclusive to certain luxury and sports car models, at least for now.