The Lexus LS takes it to the next level with an eight-speed transmission. Automatic transmissions like these can be even more fuel efficient than manual transmissions.
Generally speaking, having more transmission speeds - or gear ratios - to choose from improves fuel economy by allowing the engine to operate in its most efficient speed range more of the time. More speeds also allow high gears to be even higher, for more efficient highway cruising.
While these transmissions will, on on their own, only improve efficiently slightly, what customers are more likely to notice is the way the car drives. More speeds means a smoother, quieter ride.
Beyond six-, seven- or eight-speed transmissions, some hybrid cars and smaller cars use continuously variable transmissions in which gear ratios change in a smooth flow rather than step-by-step. While these transmissions are very efficient, they aren't suited for use with more powerful engines or where towing ability is needed.
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