I have changed my riding goals for this fall, instead of doing a 200k brevet in 3 weeks, I will ride a century before the winter.

I have found this "wall" at about 5-5.5 hours into my ride. I think it is more a time-in-saddle issue than an actual mileage thing - right now that is about 68-70 miles for me - I am still slow which is one of the reasons why I have put off the brevet.

The more thinking/research I do, it seems to be a nutritional issue than anything. I have begun to wonder if I am doing something wrong in those first couple of hours that I am paying for once I cross that 5-hour mark.

I am wondering if you more experienced riders approach your nutrition on the bike differently for rides > 5-6 hours? I know that everyone is different, just wondering how others approach this. My endurance is fine - until I hit that wall and my energy just drops to nothing pretty suddenly- I think that I am starting to bonk at that point.