I had some problems installing the brackets for my small handlebar bag on my new CoMo tandem. The handlebars were wide enough diameter so that I didn't need the included spacer rings at all. One bracket went on easily but the other was a bit troublesome when trying to start the bolt into the thread. Finally got it though after about ten minutes. One thing I found a little problematic though was that I had to route my gearing cables through the bracket in order for the bag to fit properly without fouling my cables. That meant I had to unwrap both sets of bar tape, route the cable properly, and retape. Not a huge undertaking and I am glad I did it. Was trying to think of a new configuration for the brackets that wouldn't require untaping, etc but I'll leave that to Arkel. We just got back from our first 5 day, fully loaded, tandem trip (front and rear panniers plus a Burley Nomad trailer). Handlebar bag performed flawlessly. In fact on our first night camping we had nowhere to keep our carton of milk cold, so I emptied the handlebar bag, removed it from the bike, put the carton in the bag and used the bag as an ice bucket. Worked like a charm.