I'm not one to say anything is impossible, and I still won't say it, but I've been trying to figure this one out for months. I've talked to some tech reps at Trek's HQ in Waterloo and they do not know of any way for a guide to be mounted. The problem lies in the BB. While the BB90 is stiff as can be, the bearings press into the frame. Without chain guide tabs or a thread in BB I do not know of any compatible guides. Trek (at the time) did not know of any way to make it happen either. If you figure a way out, PLEASE TELL ME! I love the bike, but I want a 2 ring guide.
Thanks.
Thanks.