I used to have a clip on bag on my Trek. It was a smallish-medium size that could hold all tools, food and a wind jacket folded up. But nothing fit on my Kuota! The above bag was rubbing and the guy at my shop did not want to try to make any special jerry rigged holder for a clip on bag. He did do this for my husband, whose bike is bigger and has more room for a bag. In fact, he can clip on his giant Carradice bag, which we use when touring or on longer day trips. So, the only thing that fits on my bike is a Cannondale bag that uses Velcro. It does expand, but it's not huge. All of the things I have used would be dorky to a true roadie, but hey, I am not racing. Nothing else I have is dorky, so if this bag holds all my stuff, it's fine with me! I wish I could still use my old bag, but it's not going to happen.