[MetroMPG]

The taller transmission lowered RPM by 19.8%. It was lowered a further 5.8% because the OEM tires on the Blackfly are taller than the tires originally spec'd on the taller transmission car. For a total effecive gearing change of 25.6%.

With the extra information posted in the above chart, the average difference between the measured speeds vs mpg's for the 2 transmissions is 7.9% from original. That's the most reliable baseline difference yet, since there's more speeds to compare.

But that figure also includes the effect of ambient temperature difference.