Carb/fat ratio for cycling depends on two things:
1) What you want to do.
2) What you want to tune your body to do.
There's a difference.

I'll tell you a little about a flat 202 mile ride I just did. I know about how many calories I went through, because I carry with me almost everything I eat on a ride of this length. Breakfast was ~400 cal. During the ride I tried to eat (drink, actually) about 2250 calories. I had a little left over at the end, so maybe 2000. At food stops, I grabbed ~500 cal. of this and that. Elapsed time on the ride was ~15.5 hrs., of which ~12.3 were spent pedaling. It was quite hot, so I spent a good bit of time off the bike, hydrating. So that's an moving average of ~16.4. I figure calories/hr. using elapsed time, because max intake is governed by stomach emptying time, not by pedaling time. So that was ~160 cal./hr, which was about right for that pace, as I was strong all the way to the finish. Of that, 85% or ~530g were carbs, and ~94g were protein. I eat almost no fat on a ride of that length.

I'm 69 and of below average genetics for a cyclist. I train, though. I did this ride on a tandem with my wife. 10 years ago on a single, I did this same ride in ~10 hrs. pedaling time, and under 12 hrs. elapsed, so a moving average of 19.9 for ~200 miles. That ride, I went through about the same number of calories, but in much less time, so ~210 cal./hr. I was younger, and putting out a lot more watts.

10 years ago I did my last RAMROD, 154 miles and 10,000', with a best time of ~9.5 hrs. elapsed time, or ~16 mph counting stops. Near the end, I covered 25 miles of slightly downward trending but upwind road in exactly 1 hr., so my fueling was good. For that ride, I fueled at ~250 cal./hr, as much as my stomach could take, with that same carb/protein ratio.

My weight has been about the same for the past 15 years, running about 5 lbs. over what it was when I was mountaineering in my early 20s. On a recent tour, I happened to have the opportunity to take my BP: 106/54. My doc says my lipids are "perfect."

I understand that not everyone wants to do these sorts of rides, but these sorts of rides are what the usual recommendations for macros are modeled upon. Nothing in the above is in the slightest unusual, other than I am a little older than most folks and tune my nutrition better than most folks. I hope you don't take it that I'm bragging: I'm not. There were and are many people much, much faster than I am. I was always at the back of the pack on every climb. Now I'm off the back, but I keep on keeping on.

I'm just saying, this is what almost any rider can do, and most can do much better. It does take a little knowledge of nutrition and a lot of training.

For an 80 mile group ride, 10 years ago I would go through about 1000 calories and have ~18 mph average with 4000' of climbing. If you think about what I've been saying and do a little calculating, you'll see that, though I figure by the hour, I actually eat by the mile, not so much by the hour, at a rate of ~12.5 cal./mile for rides of up to 200 miles, slightly more for rides with a lot of climbing.