Do you mean why won't your SCS slide onto your fork? If that's the case, most of the time it is kind of hard to put the SCS on the fork, but it's not impossible. If it looks like it's just a tight fit, get a rubber mallet or something softer than a hammer, but still something you can whack it with, and hit it on. I'm not sure if this is what you're asking, but I tried.
