the Tektro RL721is a cross top lever meant for use as auxiliary levers on the tops of a drop bar. why are you (apparently) using them as your main lever?

also , as they are a road bike lever, they are meant for use with caliper brakes; which is a different cable pull than v-brakes
you need a v-brakes specific brake lever, v-brakes need longer cable travel than calipers
-thus your current problems with inadequate rim clearance

bottom line: your brake lever is incompatible with v-brakes

get this
http://www.amazon.com/Shimano-BL-M42...=v-brake+lever