First, thanks for any help. I've recently picked up a cheap Univega hybrid to leave at the family cabin for rides. It's drivetrain is in pretty rough shape. Several teeth are missing (or very worn down) on the cassette and large chainring. I have a new cassette and chain ready to go, but I'm unsure how exactly to measure the BCD to replace the large chainring. It is 5 bolt, 42t and the crankset looks just like the one in this ebay posting (circa '96 Shimano Acera):
I'm hoping something like one of these would work, but would someone on here be able to confirm?