I wouldn't call mine 'gritty' but I agree with Sean that it's not and has never been 'buttery smooth'. By comparison, the 24-105mm focus ring is buttery smooth, but then again the much costlier 70-200mm f/2.8L IS II is a bit rough (there was a thread on that a while back). Still, those sensations seem to be constant - that little bit of roughness in my 17-55mm is there every time I turn the focus ring.


I would think there's a difference between the 'normal' feel of the focus ring and what you describe as feeling a grinding every once in a while. The latter suggests that there may be a small particle of some sort trapped under the ring or in the mechanism somewhere. I did notice that with one lens I had, the 70-300mm DO (which I bought used about 3 months ago and sold just yesterday) - most of the time it was smooth, but every once in a while there was something I'd have to call a grinding feel, that was only as I rotated past one spot. It would grind once or twice like that, then stop. To me, that sounds like a particle caught in the mechanism that works its way into a tight spot then slips back into a nook or cranny.


Personally, I agree with Sean - I would not try a DIY repair!