Taking SCARY out of used bikes, one bike at a time.

That Doesn’t Line-Up!
When a drivetrain has been ridden hard, and parts are not replaced when worn out. It can lead up to many parts that need to be replaced. In this case, it looks like they just stayed in on gear upfront and one or two in the back. Trainer bike, I’m guessing. 
When the chains are stretched and aren’t replaced, it can damage the cassette and chainring. So when looking at a used bike or your own, inspect the chainrings, cassette, and jockey pulleys. Look for ware because there may be some hidden cost down the road.
Other Related Posts:
https://iknowaguybicycles.com/all-cracked-up/
https://iknowaguybicycles.com/is-chain-stretch-real/
https://iknowaguybicycles.com/oh-no-thats-not-right/