I'm a big fan of frame bags, but looking for one slightly bigger and more versatile than my present one. I usually carry my ulock, flat kit, a small lunch, and once, eight beers. I didn't purchase this bag. The sales person welcomed me to bring my bike in the store and put the bag on for fitting. I have an admittedly smaller track frame, but the bag fit (snugly) within. I really liked the handle at the top. A feature I really appreciated was the water bottle pocket. It was great. I believe everything I wanted to put in a frame bag would work... and then some. I think ultimately the bag is 1.5-2" too wide. On a test ride, if I paid attention, my knees wouldn't hit the bag, but I knew on a trail or path, if I wasn't thinking about it, I would scrape the outer shell easily. I think it could use a better support strap on the back corner, and maybe midway across the top, it sags without anything even in it. I'm contemplating a 500 mile ride next summer, and would consider this bag for that, but not my daily commute.