One might wish to decide how much of a gearing change one wishes to achieve. The change in ratios discussed so far range from a bit over 4% to a bit ovr 14%. Be aware that while a 16 tooth will have engine operating at about 14% less rpm for any given over the ground speed it conversely will not make the bike go 14% faster. Not sure if even the 4% gearing change of a 47 vs 49 tooth rear sprocket will permit a 4% increase in top speed. Wind resistance, or drag, increases with the velocity squared and unfortunately the TW power output does not even increase linearly approaching the redline.