Yes. I was diagnosed pre-D after presenting with diabetic symptoms after a viral illness and now take metformin. Diet (low carb) controlled it well for a while, until it didn't. So my GP tried me on a low dose of metformin, which fixed it for a while, but then the fasting glucose started rising again. We've raised the dose 2 or 3 times so far but I'm still not at the max dose. My A1C is good and postprandial is okay, but I will just probably never have "normal" FBG.
FWIW, I have zero risk factors for diabetes, low instead of high c-peptide, but no auto-antibodies and don't fit the profile for any of the MODYs so they just figure I've got some weird genetic mutation. I'm also a cyclist, although more of a bike commuter and casual tour-taker than you; I don't race. Long hard rides sometimes make my sugars rise though, especially if the weather is hot. I keep pepperoni in my pannier for emergency fat/protein snacking to level it out! For me it seems all about finding the sweet spot dietwise (which I think is about 70g carb/day for me), taking the metformin, and accepting that whatever I figure out will probably change sometime in the future.