I have a Trek 9-series aero bike, with an X-lab aero bottle mounted on the seat tube, which, due the bottle's thinness, is too wide to allow another bottle carrier to be mounted on the down tube. I also had a bottle carrier mounted between the aero bars, but when I got an Edge 820, I installed that between the aero bars, leaving no room for the bottle carrier. I thought of installing a bottle carrier on the seat post, but then I'd lose my seat bag. Any ideas how I can get a 2nd bottle carrier on my bike without losing the 820 or seat bag?