I'm just gonna say 10 miles. I biked 16 miles instead of running. Oddly, it took me longer to do this than to just run the regular 10 miles. I would get to certain checkpoints on my ride and barely be any faster than I normally get there running, which was quite frustrating. I think this is a combination of the fact that the bike I am currently using is pretty horrible, which makes it slower than a normal bike, and since I got to college, my easy runs have gotten faster than ever. On top of that, I went my long run route, which I run the fastest (approximately 10 miles per hour), and so it sort of makes sense that my bike pace isn't exactly blowing that out of the water.