I’m looking for a rear-mount kick stand for a 2008 Cannondale T1 touring bike. The larger aluminum tubes limit what will work. Cannondale’s Eileen 2 rear-mount says it is “Designed for flat-sided tubes up to 23mm thick,” but my older 2008 tubes are NOT flat-sided.
Could you post a photo illustrating the problem in some fashion? With the info so far you aim at an advice from people who have the specific bike and have coped with the kickstand there. It is quite possible that among those reading your post, there might not a single such person, so you might be better off giving a chance to others.