I have a Shimano 13-23 on my eight-year-old, Sora equipped Trek 1000. They're no longer made, so you have to hunt them down. I stumbled upon mine two years ago. It's perfect for me. I generally ride in the 42 ring at 90-95 cadence and use all eight cogs in most rides. With 8-speed chains so cheap, I'm replacing them at 1,000 miles just to preserve this honey of a cassette.