Last weekend I was out in the California desert doing a 200 mile high speed desert run. I love passing cars on the highway while on a parallel dirt trail. I have the stock 14/48 gearing and I kept looking for another gear, but I was already in fifth. I would like to gear it down some for these rides. Will a 15 tooth countershaft sprocket fit with the stock chain guide (aka case saver) or do I need to get a larger one? If so where is one available. There is not a lot of extra clearance with the stock 14 tooth sprocket.