Originally Posted by
MetroMPG
Believe it or not, it really is as simple as that. But it costs money. And it will offend typical car reviewers.
Honda used to do it when their Civic lineup had dedicated (non-hybrid) fuel-saving models: they got taller gearing (and higher fuel economy ratings) than the "regular" models, which were also taller than the "sport" models.
Even the Geo Metro had a special high-efficiency model (US market only) with taller gearing (and a few other changes) than the "normal" Metro.
But it increases costs (development, testing, EPA/NRCAN certification, parts & marketing). Also, most car reviewers are traditional "petrol heads" who will whine, whine, whine if a car is geared "too tall" for their tastes.
Case in point: the new Ford Fiesta 1.0L ecoboost. Currently it's the car with the best non-hybrid highway fuel economy rating. And I've already read two reviewers complain about the gearing being too tall! They want top gear responsiveness and power, not fuel economy.
Damned if you do, damned if you don't.
Also, with so few people buying manuals any more, it's easier to just have one set of ratios for the "sporty" drivers (who probably make up 90% of the ~6% of manual buyers anyway). They're now gearing the automatics significantly taller than the manuals.