The design engineers provided for longer final drive ratios in nearly every case, due to the beefy performance characteristics. Two examples of this: the ratio of the standard axle on the solo urban bus is now i=6.21 instead of i=7.37; and on the solo rural-service bus i=5.77 instead i=6.21. This move has led to a considerably lower engine speed and noise level and reduced the number of comfort-inhibiting gearshifts at the same time.
The driver will not only feel how the engine has changed, but see it, too: the area on the rev counter marked in green, which shows the most economical shift range, starts at 900 rpm in the Citaro.
Overall, thanks to the reduced engine speed levels, the new Citaro complying with the Euro VI emissions standard is not just even more economical to drive, but quieter too, and also easy on the ear from a subjective point of view. This is due, in addition to the lower engine speeds, to improved sound insulation and the new injection process.