hey guys im working on cleaning up an 83 Schwinn traveler that i got from my dad. my problem is that the front and rear derailleurs are broken (the rear one isn't even all there). i have no clue what derailleurs i should pick. it has 6 sprockets in the rear and 2 on the front with 28 teeth and 52 teeth respectively. i don't need a $300 derailleur this bike will only be used for riding on campus for getting from a to b. thanks in advance guys.