Flagstaff? There shouldn't be that much of a problem as far as bike thefts compared to other cities. Depending where in the city you live in. I'd say time is what I'd base it on and if the bike is left in the same place everyday.

honestly, a few friends and i decided to bike about 15 miles and i tell ya, it wasnt fun with bmx lol. i just used a regular cable lock

lol 15 miles is nothing.

from my house to downtown is 15 miles. its nothinnnnnnnnn