Six-speed usually is heavier and adds weight to the car but it compensates for this by having lower gear ratios and better fuel mileage when topping out at fifth and sixth gears.
Six-speed is usually more expensive. Five-speed transmissions weigh less.
Both five- and six- speeds have almost the same gear ratios from first to fifth gears, and the sixth gear is only meant for overdrive purposes, for
When tested on cars that come in both five-speed and six-speed, like the Mazda Miata, the final drive didn’t vary much between the two transmission types when compared head to head.
Here is an oversimplified definition of six-speed transmission: An overdrive gear is added to a standard five-speed. Or the top gear is the same in sixth but the rest of the lower gear ratios are pushed closer to each other.
As a closed gearbox, six-speed means you would have to shift sooner from first to second, compared to what you usually do in using a five-speed box. A six-speed usually allows better acceleration and still retains top speed.
A five-speed is more beneficial in low power cars (under 100 HP) with a flat torque curve and a wide powerband (the range of operating speeds the engine can run efficiently).
For motorists who want to rip the track, six-speeds are preferred, usually for bragging rights, even if it reduces acceleration from 1-100 mph by 0.5 of a second. It isn’t much use in city driving, though. For city driving, there really isn’t that much noticeable difference if both five-speed and six-speed have the same top end. Sportier cars are usually the vehicles that have the option for sixth gear, usually to keep fuel mileage respectable when cruising down the highway.