Well your pulling almost 71 gear inches and that's about average
for a road bike. You must be doing short twenty mile or less rides
on flat roads or your a brute. You can easily figure out the ratios
or gear inches: 42/16=2.625x27=70.875 (for road tires) about 71
inches. Or here is a gear calc for ya.

http://www.bikeschool.com/

-VÈÑÍ VÍÐÌ VÌÇÍ.