Originally Posted by
mlmack
http://blog.sew-classic.com/2010/02/...hine-belt.aspx
The stretchy ones are harder to judge because they stretch. I would loosen up the motor bracket, install the belt, and just make sure the belt is just tight enough to turn the motor and balance wheel without slipping.
I would pay the OSMG to show me how (if he is willing) and you don't know.
The above link to Sew classic has good info on belts.