I just had my chain replaced — my old one was 100% worn and stretched badly. The bike shop who changed it was able to make the new chain work with my old cassette. However, my “go to” gear (the one I primarily ride in — Florida), has been slipping when I am climbing or putting heavy pressure on it. I’m thinking that ring on my cassette is worn from the old chain. Am I on the right track? I’d like to try to correct the problem on my own and install a cassette myself if so. Thanks!
More than likely you will need a new cassette and possibly new chain rings as well. Get your self a chain checker tool. They’re cheap and will let you know when it’s time to replace your chain. Replacing your chain when it needs it will give you more life out of your cassette and rings. And replacing a chain is much less expensive than a whole new drivetrain!