I've recently started riding more seriously with a team, so I'm getting a lot more feedback on things I just assumed were normal before, and one of my teammates told me yesterday that I probably needed a different cassette, since my legs were spinning very quickly in my highest available gear. I'm currently running a SRAM Force set-up with a 12-25. My coach said something about me getting an 11-27, but that doesn't seem to exist on the SRAM website. Wondering what options I should be looking at...

Please bear with any cluelessness on my part...I've been trying to research this my own, but haven't really been able to wrap my brain around these things independently. I could always go back and ask my coach for more info, but figured I'd try to get a broader knowledge base from BF first!