Doing my monthly inspection & clean of my wheels last night and I was shocked to see a crack around one the spokes as they enter rim. It is a rear wheel (Shimano R600 I think). I had obviously been riding on it for a little while, so I was wondering if there was any urgency in getting the rim replaced, or can I wait until my next visit to my LBSLBS? I currently do only around 100km per week.