I'm replacing the tension stud the smaller bolt that the spring goes against and the tensioner roller and spring ... but should I replace larger bolt that the tensioner roller goes on ... also whats the best way to get off a stud that has threads on both sides

 

Put 2 nuts on the end of the stud. tighten them against each other, then put the wrench on the inside one, and loosen... Wah-lah!

 

thats a real good idea thanks ... what about the bigger bolt that the tensioner roller goes on should i replace it